Nutrient chapter

Caffeine

Caffeine. Species, exposure and limitations are retained in each linked claim.

89 recorded mechanisms · 2 availability situations · 10 preserved sources. Draft and verified records are labeled separately.

Read recorded mechanisms Open recursive mind map

The mechanisms

What the sources say this nutrient does, one relationship at a time. Plain wording comes first; the technical statement follows.

Caffeine displaced 5–44% of the A1 PET ligand signal; modeled half-maximal displacement corresponded to plasma caffeine of 67 micromolar.
Caffeine → Human adenosine A1 receptor / ADORA1 source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
15 adults; 0.5–4.3 mg/kg intravenous caffeine after at least 36 hours abstinence; one vehicle subject.
limitations
PET occupancy does not establish that A1 alone mediates wakefulness or a universal oral-dose threshold.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Caffeine reached and occupied adenosine receptors in the human brain.
primary_references
Caffeine occupancy of human cerebral A1 adenosine receptors: in vivo quantification with 18F-CPFPX and PET. · 2012 · https://pubmed.ncbi.nlm.nih.gov/22966134/ · DOI 10.2967/jnumed.112.105114
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 20–26
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · 15 adults; 0.5–4.3 mg/kg intravenous caffeine after at least 36 hours abstinence; one vehicle subject. · source_derived_draft · unverified_draft
## caf-human-a1 Caffeine reached and occupied adenosine receptors in the human brain. Caffeine displaced 5–44% of the A1 PET ligand signal; modeled half-maximal displacement corresponded to plasma caffeine of 67 micromolar. Model: 15 adults; 0.5–4.3 mg/kg intravenous caffeine after at least 36 hours abstinence; one vehicle subject. Limitations: PET occupancy does not establish that A1 alone mediates wakefulness or a universal oral-dose threshold. Evidence access: Primary abstract Caffeine occupancy of human cerebral A1 adenosine receptors: in vivo quantification with 18F-CPFPX and PET. · 2012 · https://pubmed.ncbi.nlm.nih.gov/22966134/ · DOI 10.2967/jnumed.112.105114
Complete structured claim and evidence
Crystallography resolved caffeine in a thermostabilized A2A receptor with an inactive-state conformation.
Caffeine → Thermostabilized human A2A receptor crystallography construct source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Engineered human receptor construct; crystallographic comparison with XAC and ZM241385.
limitations
Engineered inactive-state structure, not a measurement of native receptor signaling in a person.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
A receptor structure shows where caffeine binds.
primary_references
Structure of the adenosine A(2A) receptor in complex with ZM241385 and the xanthines XAC and caffeine. · 2011 · https://pubmed.ncbi.nlm.nih.gov/21885291/ · DOI 10.1016/j.str.2011.06.014
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AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Engineered human receptor construct; crystallographic comparison with XAC and ZM241385. · source_derived_draft · unverified_draft
## caf-a2a-structure A receptor structure shows where caffeine binds. Crystallography resolved caffeine in a thermostabilized A2A receptor with an inactive-state conformation. Model: Engineered human receptor construct; crystallographic comparison with XAC and ZM241385. Limitations: Engineered inactive-state structure, not a measurement of native receptor signaling in a person. Evidence access: Primary abstract Structure of the adenosine A(2A) receptor in complex with ZM241385 and the xanthines XAC and caffeine. · 2011 · https://pubmed.ncbi.nlm.nih.gov/21885291/ · DOI 10.1016/j.str.2011.06.014
Complete structured claim and evidence
Caffeine at 5, 10 and 15 mg/kg increased wakefulness in wild-type and A1-knockout mice, but not A2A-knockout mice.
Mouse adenosine A2A receptor / Adora2a → Wakefulness in mice source_derived_draftungraded
Experimental context and source evidence
availability_state
machinery_impairment Imported condition classification; unverified.
evidence_access
Primary abstract
experimental_model
Receptor-knockout mouse comparison.
limitations
Species and endpoint specific; this does not contradict human A1 binding or exclude other A1 functions.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Removing A2A receptors removed the wakefulness response in mice.
primary_references
Adenosine A2A, but not A1, receptors mediate the arousal effect of caffeine. · 2005 · https://pubmed.ncbi.nlm.nih.gov/15965471/ · DOI 10.1038/nn1491
trigger_kind
machinery_impairment Imported condition classification; unverified.
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 36–42
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Receptor-knockout mouse comparison. · source_derived_draft · unverified_draft
## caf-a2a-wake Removing A2A receptors removed the wakefulness response in mice. Caffeine at 5, 10 and 15 mg/kg increased wakefulness in wild-type and A1-knockout mice, but not A2A-knockout mice. Model: Receptor-knockout mouse comparison. Limitations: Species and endpoint specific; this does not contradict human A1 binding or exclude other A1 functions. Evidence access: Primary abstract Adenosine A2A, but not A1, receptors mediate the arousal effect of caffeine. · 2005 · https://pubmed.ncbi.nlm.nih.gov/15965471/ · DOI 10.1038/nn1491
Complete structured claim and evidence
Injected caffeine increased locomotion only in mice expressing A2A receptors; ingestion also produced an A2A-dependent increase in males.
Mouse adenosine A2A receptor / Adora2a → Locomotor activity in mice source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Awake receptor-knockout mice; telemetry and respirometry.
limitations
Sex and route mattered; locomotion is not a direct measure of human focus.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
The activity response depended on this receptor in the mouse experiment.
primary_references
Physiological roles of A1 and A2A adenosine receptors in regulating heart rate, body temperature, and locomotion as revealed using knockout mice and caffeine. · 2009 · https://pubmed.ncbi.nlm.nih.gov/19218506/ · DOI 10.1152/ajpheart.00754.2008
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 44–50
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Awake receptor-knockout mice; telemetry and respirometry. · source_derived_draft · unverified_draft
## caf-locomotion The activity response depended on this receptor in the mouse experiment. Injected caffeine increased locomotion only in mice expressing A2A receptors; ingestion also produced an A2A-dependent increase in males. Model: Awake receptor-knockout mice; telemetry and respirometry. Limitations: Sex and route mattered; locomotion is not a direct measure of human focus. Evidence access: Primary abstract Physiological roles of A1 and A2A adenosine receptors in regulating heart rate, body temperature, and locomotion as revealed using knockout mice and caffeine. · 2009 · https://pubmed.ncbi.nlm.nih.gov/19218506/ · DOI 10.1152/ajpheart.00754.2008
Complete structured claim and evidence
Caffeine ingestion increased oxygen consumption in wild-type mice, with smaller responses in receptor-knockout groups.
Caffeine → Whole-body oxygen consumption in mice source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
A1, A2A and double-knockout mouse comparison.
limitations
Not evidence of durable weight loss in humans.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Receptor status changed the animal metabolic response.
primary_references
Physiological roles of A1 and A2A adenosine receptors in regulating heart rate, body temperature, and locomotion as revealed using knockout mice and caffeine. · 2009 · https://pubmed.ncbi.nlm.nih.gov/19218506/ · DOI 10.1152/ajpheart.00754.2008
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 52–58
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · A1, A2A and double-knockout mouse comparison. · source_derived_draft · unverified_draft
## caf-oxygen Receptor status changed the animal metabolic response. Caffeine ingestion increased oxygen consumption in wild-type mice, with smaller responses in receptor-knockout groups. Model: A1, A2A and double-knockout mouse comparison. Limitations: Not evidence of durable weight loss in humans. Evidence access: Primary abstract Physiological roles of A1 and A2A adenosine receptors in regulating heart rate, body temperature, and locomotion as revealed using knockout mice and caffeine. · 2009 · https://pubmed.ncbi.nlm.nih.gov/19218506/ · DOI 10.1152/ajpheart.00754.2008
Complete structured claim and evidence
Injected caffeine at 30 mg/kg lowered body temperature, especially in receptor-knockout mice, suggesting an effect beyond A1/A2A blockade.
Caffeine → Body temperature in mice source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Mouse high-dose injection experiment.
limitations
The additional molecular target was not identified.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
A higher dose produced effects that the two main receptors did not explain.
primary_references
Physiological roles of A1 and A2A adenosine receptors in regulating heart rate, body temperature, and locomotion as revealed using knockout mice and caffeine. · 2009 · https://pubmed.ncbi.nlm.nih.gov/19218506/ · DOI 10.1152/ajpheart.00754.2008
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 60–66
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Mouse high-dose injection experiment. · source_derived_draft · unverified_draft
## caf-temperature A higher dose produced effects that the two main receptors did not explain. Injected caffeine at 30 mg/kg lowered body temperature, especially in receptor-knockout mice, suggesting an effect beyond A1/A2A blockade. Model: Mouse high-dose injection experiment. Limitations: The additional molecular target was not identified. Evidence access: Primary abstract Physiological roles of A1 and A2A adenosine receptors in regulating heart rate, body temperature, and locomotion as revealed using knockout mice and caffeine. · 2009 · https://pubmed.ncbi.nlm.nih.gov/19218506/ · DOI 10.1152/ajpheart.00754.2008
Complete structured claim and evidence
Caffeine 300 mg increased D2/D3 PET availability in putamen and ventral striatum, but not caudate, in 20 healthy participants.
Caffeine → Striatal dopamine D2/D3 receptor availability measured by PET source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Human raclopride PET, caffeine versus placebo.
limitations
Availability can reflect receptor levels or affinity. The direction did not support a simple increase in striatal dopamine release; receptor upregulation was an interpretation.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Caffeine changed a dopamine-receptor measurement in selected brain regions.
primary_references
Caffeine increases striatal dopamine D2/D3 receptor availability in the human brain. · 2015 · https://pubmed.ncbi.nlm.nih.gov/25871974/ · DOI 10.1038/tp.2015.46
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AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Human raclopride PET, caffeine versus placebo. · source_derived_draft · unverified_draft
## caf-dopamine-pet Caffeine changed a dopamine-receptor measurement in selected brain regions. Caffeine 300 mg increased D2/D3 PET availability in putamen and ventral striatum, but not caudate, in 20 healthy participants. Model: Human raclopride PET, caffeine versus placebo. Limitations: Availability can reflect receptor levels or affinity. The direction did not support a simple increase in striatal dopamine release; receptor upregulation was an interpretation. Evidence access: Primary abstract Caffeine increases striatal dopamine D2/D3 receptor availability in the human brain. · 2015 · https://pubmed.ncbi.nlm.nih.gov/25871974/ · DOI 10.1038/tp.2015.46
Complete structured claim and evidence
Caffeine three hours before habitual bedtime delayed the human melatonin rhythm by approximately 40 minutes.
Caffeine → Phase of the endogenous melatonin circadian rhythm source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Double-blind within-subject circadian experiment lasting about 49 days.
limitations
A study-specific phase shift, not a fixed effect in every person; endogenous timing differs from clearance of a melatonin supplement.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Caffeine shifted internal timing as well as wakefulness.
primary_references
Effects of caffeine on the human circadian clock in vivo and in vitro. · 2015 · https://pubmed.ncbi.nlm.nih.gov/26378246/ · DOI 10.1126/scitranslmed.aac5125
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AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Double-blind within-subject circadian experiment lasting about 49 days. · source_derived_draft · unverified_draft
## caf-clock-human Caffeine shifted internal timing as well as wakefulness. Caffeine three hours before habitual bedtime delayed the human melatonin rhythm by approximately 40 minutes. Model: Double-blind within-subject circadian experiment lasting about 49 days. Limitations: A study-specific phase shift, not a fixed effect in every person; endogenous timing differs from clearance of a melatonin supplement. Evidence access: Primary abstract Effects of caffeine on the human circadian clock in vivo and in vitro. · 2015 · https://pubmed.ncbi.nlm.nih.gov/26378246/ · DOI 10.1126/scitranslmed.aac5125
Complete structured claim and evidence
Caffeine lengthened the circadian reporter period dose-dependently in U2OS cells.
Caffeine → Circadian reporter period in human U2OS cells source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Human osteosarcoma cells with clock-gene luciferase reporters.
limitations
Cell period is not identical to human sleep duration.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
The effect also reached a cellular clock model.
primary_references
Effects of caffeine on the human circadian clock in vivo and in vitro. · 2015 · https://pubmed.ncbi.nlm.nih.gov/26378246/ · DOI 10.1126/scitranslmed.aac5125
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 84–90
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Human osteosarcoma cells with clock-gene luciferase reporters. · source_derived_draft · unverified_draft
## caf-clock-cell The effect also reached a cellular clock model. Caffeine lengthened the circadian reporter period dose-dependently in U2OS cells. Model: Human osteosarcoma cells with clock-gene luciferase reporters. Limitations: Cell period is not identical to human sleep duration. Evidence access: Primary abstract Effects of caffeine on the human circadian clock in vivo and in vitro. · 2015 · https://pubmed.ncbi.nlm.nih.gov/26378246/ · DOI 10.1126/scitranslmed.aac5125
Complete structured claim and evidence
A cAMP biosensor detected increased cAMP; pharmacological and knockdown experiments supported adenosine-receptor signaling rather than RyR or PDE perturbation as sufficient to explain the clock effect.
Caffeine → Cyclic adenosine monophosphate source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
U2OS cAMP biosensor and pathway perturbations.
limitations
Does not exclude high-concentration PDE or calcium-channel effects in other systems.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
The clock experiment identified a receptor-linked signaling route.
primary_references
Effects of caffeine on the human circadian clock in vivo and in vitro. · 2015 · https://pubmed.ncbi.nlm.nih.gov/26378246/ · DOI 10.1126/scitranslmed.aac5125
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 92–98
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · U2OS cAMP biosensor and pathway perturbations. · source_derived_draft · unverified_draft
## caf-clock-camp The clock experiment identified a receptor-linked signaling route. A cAMP biosensor detected increased cAMP; pharmacological and knockdown experiments supported adenosine-receptor signaling rather than RyR or PDE perturbation as sufficient to explain the clock effect. Model: U2OS cAMP biosensor and pathway perturbations. Limitations: Does not exclude high-concentration PDE or calcium-channel effects in other systems. Evidence access: Primary abstract Effects of caffeine on the human circadian clock in vivo and in vitro. · 2015 · https://pubmed.ncbi.nlm.nih.gov/26378246/ · DOI 10.1126/scitranslmed.aac5125
Complete structured claim and evidence
A fixed 400 mg dose at bedtime, three hours before, or six hours before increased sleep disturbance relative to placebo.
Caffeine → Sleep disturbance in the specified trial source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Home crossover study with subjective reports and a portable sleep monitor.
limitations
This experiment does not define an individualized cutoff for every dose or metabolism rate.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Caffeine disrupted sleep even when taken well before bedtime.
primary_references
Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. · 2013 · https://pubmed.ncbi.nlm.nih.gov/24235903/ · DOI 10.5664/jcsm.3170
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AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Home crossover study with subjective reports and a portable sleep monitor. · source_derived_draft · unverified_draft
## caf-sleep Caffeine disrupted sleep even when taken well before bedtime. A fixed 400 mg dose at bedtime, three hours before, or six hours before increased sleep disturbance relative to placebo. Model: Home crossover study with subjective reports and a portable sleep monitor. Limitations: This experiment does not define an individualized cutoff for every dose or metabolism rate. Evidence access: Primary abstract Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. · 2013 · https://pubmed.ncbi.nlm.nih.gov/24235903/ · DOI 10.5664/jcsm.3170
Complete structured claim and evidence
At 24 hours after placebo substitution, withdrawal increased middle- and anterior-cerebral arterial flow velocities.
Acute withdrawal after repeated caffeine exposure → Cerebral arterial blood-flow velocity source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
16 regular users; double-blind within-subject study; at least 14 days on 400 mg/day or placebo, with acute challenges.
limitations
Withdrawal is adaptation to repeated exposure, not an essential-nutrient deficiency. Blood-flow velocity is not absolute cerebral perfusion.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Stopping after repeated use produced a measurable response.
primary_references
Caffeine withdrawal, acute effects, tolerance, and absence of net beneficial effects of chronic administration: cerebral blood flow velocity, quantitative EEG, and subjective effects. · 2009 · https://pubmed.ncbi.nlm.nih.gov/19241060/ · DOI 10.1007/s00213-009-1489-4
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AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · 16 regular users; double-blind within-subject study; at least 14 days on 400 mg/day or placebo, with acute challenges. · source_derived_draft · unverified_draft
## caf-withdraw-flow Stopping after repeated use produced a measurable response. At 24 hours after placebo substitution, withdrawal increased middle- and anterior-cerebral arterial flow velocities. Model: 16 regular users; double-blind within-subject study; at least 14 days on 400 mg/day or placebo, with acute challenges. Limitations: Withdrawal is adaptation to repeated exposure, not an essential-nutrient deficiency. Blood-flow velocity is not absolute cerebral perfusion. Evidence access: Primary abstract Caffeine withdrawal, acute effects, tolerance, and absence of net beneficial effects of chronic administration: cerebral blood flow velocity, quantitative EEG, and subjective effects. · 2009 · https://pubmed.ncbi.nlm.nih.gov/19241060/ · DOI 10.1007/s00213-009-1489-4
Complete structured claim and evidence
Acute withdrawal increased EEG theta power.
Acute withdrawal after repeated caffeine exposure → EEG theta power source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
16 regular users; double-blind within-subject study; at least 14 days on 400 mg/day or placebo, with acute challenges.
limitations
Withdrawal is adaptation to repeated exposure, not an essential-nutrient deficiency. Blood-flow velocity is not absolute cerebral perfusion.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Stopping after repeated use produced a measurable response.
primary_references
Caffeine withdrawal, acute effects, tolerance, and absence of net beneficial effects of chronic administration: cerebral blood flow velocity, quantitative EEG, and subjective effects. · 2009 · https://pubmed.ncbi.nlm.nih.gov/19241060/ · DOI 10.1007/s00213-009-1489-4
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AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · 16 regular users; double-blind within-subject study; at least 14 days on 400 mg/day or placebo, with acute challenges. · source_derived_draft · unverified_draft
## caf-withdraw-theta Stopping after repeated use produced a measurable response. Acute withdrawal increased EEG theta power. Model: 16 regular users; double-blind within-subject study; at least 14 days on 400 mg/day or placebo, with acute challenges. Limitations: Withdrawal is adaptation to repeated exposure, not an essential-nutrient deficiency. Blood-flow velocity is not absolute cerebral perfusion. Evidence access: Primary abstract Caffeine withdrawal, acute effects, tolerance, and absence of net beneficial effects of chronic administration: cerebral blood flow velocity, quantitative EEG, and subjective effects. · 2009 · https://pubmed.ncbi.nlm.nih.gov/19241060/ · DOI 10.1007/s00213-009-1489-4
Complete structured claim and evidence
Acute withdrawal decreased EEG beta-2 power.
Acute withdrawal after repeated caffeine exposure → EEG beta-2 power source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
16 regular users; double-blind within-subject study; at least 14 days on 400 mg/day or placebo, with acute challenges.
limitations
Withdrawal is adaptation to repeated exposure, not an essential-nutrient deficiency. Blood-flow velocity is not absolute cerebral perfusion.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Stopping after repeated use produced a measurable response.
primary_references
Caffeine withdrawal, acute effects, tolerance, and absence of net beneficial effects of chronic administration: cerebral blood flow velocity, quantitative EEG, and subjective effects. · 2009 · https://pubmed.ncbi.nlm.nih.gov/19241060/ · DOI 10.1007/s00213-009-1489-4
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AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · 16 regular users; double-blind within-subject study; at least 14 days on 400 mg/day or placebo, with acute challenges. · source_derived_draft · unverified_draft
## caf-withdraw-beta Stopping after repeated use produced a measurable response. Acute withdrawal decreased EEG beta-2 power. Model: 16 regular users; double-blind within-subject study; at least 14 days on 400 mg/day or placebo, with acute challenges. Limitations: Withdrawal is adaptation to repeated exposure, not an essential-nutrient deficiency. Blood-flow velocity is not absolute cerebral perfusion. Evidence access: Primary abstract Caffeine withdrawal, acute effects, tolerance, and absence of net beneficial effects of chronic administration: cerebral blood flow velocity, quantitative EEG, and subjective effects. · 2009 · https://pubmed.ncbi.nlm.nih.gov/19241060/ · DOI 10.1007/s00213-009-1489-4
Complete structured claim and evidence
Withdrawal increased tiredness/fatigue ratings and decreased energy/vigor ratings.
Acute withdrawal after repeated caffeine exposure → Subjective fatigue source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
16 regular users; double-blind within-subject study; at least 14 days on 400 mg/day or placebo, with acute challenges.
limitations
Withdrawal is adaptation to repeated exposure, not an essential-nutrient deficiency. Blood-flow velocity is not absolute cerebral perfusion.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Stopping after repeated use produced a measurable response.
primary_references
Caffeine withdrawal, acute effects, tolerance, and absence of net beneficial effects of chronic administration: cerebral blood flow velocity, quantitative EEG, and subjective effects. · 2009 · https://pubmed.ncbi.nlm.nih.gov/19241060/ · DOI 10.1007/s00213-009-1489-4
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AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · 16 regular users; double-blind within-subject study; at least 14 days on 400 mg/day or placebo, with acute challenges. · source_derived_draft · unverified_draft
## caf-withdraw-fatigue Stopping after repeated use produced a measurable response. Withdrawal increased tiredness/fatigue ratings and decreased energy/vigor ratings. Model: 16 regular users; double-blind within-subject study; at least 14 days on 400 mg/day or placebo, with acute challenges. Limitations: Withdrawal is adaptation to repeated exposure, not an essential-nutrient deficiency. Blood-flow velocity is not absolute cerebral perfusion. Evidence access: Primary abstract Caffeine withdrawal, acute effects, tolerance, and absence of net beneficial effects of chronic administration: cerebral blood flow velocity, quantitative EEG, and subjective effects. · 2009 · https://pubmed.ncbi.nlm.nih.gov/19241060/ · DOI 10.1007/s00213-009-1489-4
Complete structured claim and evidence
Tolerance occurred on subjective measures but not the measured physiological endpoints; chronic effects remained mainly on EEG beta-2 power.
Caffeine → Subjective fatigue source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
16 regular users; double-blind within-subject study; at least 14 days on 400 mg/day or placebo, with acute challenges.
limitations
No universal claim that caffeine never benefits performance; these results concern the selected outcomes and schedule.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Feeling tolerant did not mean every measured response had disappeared.
primary_references
Caffeine withdrawal, acute effects, tolerance, and absence of net beneficial effects of chronic administration: cerebral blood flow velocity, quantitative EEG, and subjective effects. · 2009 · https://pubmed.ncbi.nlm.nih.gov/19241060/ · DOI 10.1007/s00213-009-1489-4
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AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · 16 regular users; double-blind within-subject study; at least 14 days on 400 mg/day or placebo, with acute challenges. · source_derived_draft · unverified_draft
## caf-tolerance Feeling tolerant did not mean every measured response had disappeared. Tolerance occurred on subjective measures but not the measured physiological endpoints; chronic effects remained mainly on EEG beta-2 power. Model: 16 regular users; double-blind within-subject study; at least 14 days on 400 mg/day or placebo, with acute challenges. Limitations: No universal claim that caffeine never benefits performance; these results concern the selected outcomes and schedule. Evidence access: Primary abstract Caffeine withdrawal, acute effects, tolerance, and absence of net beneficial effects of chronic administration: cerebral blood flow velocity, quantitative EEG, and subjective effects. · 2009 · https://pubmed.ncbi.nlm.nih.gov/19241060/ · DOI 10.1007/s00213-009-1489-4
Complete structured claim and evidence
Repeated caffeine exposure increased neutrophil A2A receptor binding density.
Caffeine → Human neutrophil A2A receptor density source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Human neutrophils after 400 or 600 mg/day for one week, or 400 mg/day for two weeks; ex-vivo binding and NECA challenges.
limitations
Adapted cells were challenged with an agonist; this is not the same as an immediate effect of caffeine, nor a clinical anti-inflammatory trial.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Repeated exposure changed receptor abundance in immune cells.
primary_references
Caffeine intake induces an alteration in human neutrophil A2A adenosine receptors. · 2005 · https://pubmed.ncbi.nlm.nih.gov/16143823/ · DOI 10.1007/s00018-005-5312-z
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AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Human neutrophils after 400 or 600 mg/day for one week, or 400 mg/day for two weeks; ex-vivo binding and NECA challenges. · source_derived_draft · unverified_draft
## caf-neutrophil-density Repeated exposure changed receptor abundance in immune cells. Repeated caffeine exposure increased neutrophil A2A receptor binding density. Model: Human neutrophils after 400 or 600 mg/day for one week, or 400 mg/day for two weeks; ex-vivo binding and NECA challenges. Limitations: Adapted cells were challenged with an agonist; this is not the same as an immediate effect of caffeine, nor a clinical anti-inflammatory trial. Evidence access: Primary abstract Caffeine intake induces an alteration in human neutrophil A2A adenosine receptors. · 2005 · https://pubmed.ncbi.nlm.nih.gov/16143823/ · DOI 10.1007/s00018-005-5312-z
Complete structured claim and evidence
After caffeine exposure, NECA stimulation produced greater cAMP accumulation.
Caffeine → Human neutrophil cAMP response to NECA source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Human neutrophils after 400 or 600 mg/day for one week, or 400 mg/day for two weeks; ex-vivo binding and NECA challenges.
limitations
Adapted cells were challenged with an agonist; this is not the same as an immediate effect of caffeine, nor a clinical anti-inflammatory trial.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
The adapted cells responded more strongly to an adenosine agonist.
primary_references
Caffeine intake induces an alteration in human neutrophil A2A adenosine receptors. · 2005 · https://pubmed.ncbi.nlm.nih.gov/16143823/ · DOI 10.1007/s00018-005-5312-z
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 156–162
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Human neutrophils after 400 or 600 mg/day for one week, or 400 mg/day for two weeks; ex-vivo binding and NECA challenges. · source_derived_draft · unverified_draft
## caf-neutrophil-camp The adapted cells responded more strongly to an adenosine agonist. After caffeine exposure, NECA stimulation produced greater cAMP accumulation. Model: Human neutrophils after 400 or 600 mg/day for one week, or 400 mg/day for two weeks; ex-vivo binding and NECA challenges. Limitations: Adapted cells were challenged with an agonist; this is not the same as an immediate effect of caffeine, nor a clinical anti-inflammatory trial. Evidence access: Primary abstract Caffeine intake induces an alteration in human neutrophil A2A adenosine receptors. · 2005 · https://pubmed.ncbi.nlm.nih.gov/16143823/ · DOI 10.1007/s00018-005-5312-z
Complete structured claim and evidence
NECA-stimulated adapted neutrophils showed lower superoxide production; binding and functional changes returned to baseline after 48 hours withdrawal.
Caffeine → Human neutrophil superoxide response after NECA stimulation source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Human neutrophils after 400 or 600 mg/day for one week, or 400 mg/day for two weeks; ex-vivo binding and NECA challenges.
limitations
Adapted cells were challenged with an agonist; this is not the same as an immediate effect of caffeine, nor a clinical anti-inflammatory trial.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
The immune-cell response was reversible and depended on the agonist challenge.
primary_references
Caffeine intake induces an alteration in human neutrophil A2A adenosine receptors. · 2005 · https://pubmed.ncbi.nlm.nih.gov/16143823/ · DOI 10.1007/s00018-005-5312-z
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 164–170
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Human neutrophils after 400 or 600 mg/day for one week, or 400 mg/day for two weeks; ex-vivo binding and NECA challenges. · source_derived_draft · unverified_draft
## caf-neutrophil-superoxide The immune-cell response was reversible and depended on the agonist challenge. NECA-stimulated adapted neutrophils showed lower superoxide production; binding and functional changes returned to baseline after 48 hours withdrawal. Model: Human neutrophils after 400 or 600 mg/day for one week, or 400 mg/day for two weeks; ex-vivo binding and NECA challenges. Limitations: Adapted cells were challenged with an agonist; this is not the same as an immediate effect of caffeine, nor a clinical anti-inflammatory trial. Evidence access: Primary abstract Caffeine intake induces an alteration in human neutrophil A2A adenosine receptors. · 2005 · https://pubmed.ncbi.nlm.nih.gov/16143823/ · DOI 10.1007/s00018-005-5312-z
Complete structured claim and evidence
Caffeine N3-demethylation produced the specified dimethylxanthine; fluvoxamine reduced its formation clearance.
Caffeine → Paraxanthine source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Human caffeine/fluvoxamine crossover and metabolite measurements; eight healthy volunteers.
limitations
CYP1A2 is the principal demethylating route; minor routes and individual clearance vary.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Caffeine produces a distinct metabolite that needs its own record.
primary_references
A fluvoxamine-caffeine interaction study. · 1996 · https://pubmed.ncbi.nlm.nih.gov/8807660/ · DOI 10.1097/00008571-199606000-00003
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AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Human caffeine/fluvoxamine crossover and metabolite measurements; eight healthy volunteers. · source_derived_draft · unverified_draft
## caf-met-px Caffeine produces a distinct metabolite that needs its own record. Caffeine N3-demethylation produced the specified dimethylxanthine; fluvoxamine reduced its formation clearance. Model: Human caffeine/fluvoxamine crossover and metabolite measurements; eight healthy volunteers. Limitations: CYP1A2 is the principal demethylating route; minor routes and individual clearance vary. Evidence access: Primary abstract A fluvoxamine-caffeine interaction study. · 1996 · https://pubmed.ncbi.nlm.nih.gov/8807660/ · DOI 10.1097/00008571-199606000-00003
Complete structured claim and evidence
Caffeine N1-demethylation produced the specified dimethylxanthine; fluvoxamine reduced its formation clearance.
Caffeine → Theobromine source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Human caffeine/fluvoxamine crossover and metabolite measurements; eight healthy volunteers.
limitations
CYP1A2 is the principal demethylating route; minor routes and individual clearance vary.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Caffeine produces a distinct metabolite that needs its own record.
primary_references
A fluvoxamine-caffeine interaction study. · 1996 · https://pubmed.ncbi.nlm.nih.gov/8807660/ · DOI 10.1097/00008571-199606000-00003
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 180–186
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Human caffeine/fluvoxamine crossover and metabolite measurements; eight healthy volunteers. · source_derived_draft · unverified_draft
## caf-met-tb Caffeine produces a distinct metabolite that needs its own record. Caffeine N1-demethylation produced the specified dimethylxanthine; fluvoxamine reduced its formation clearance. Model: Human caffeine/fluvoxamine crossover and metabolite measurements; eight healthy volunteers. Limitations: CYP1A2 is the principal demethylating route; minor routes and individual clearance vary. Evidence access: Primary abstract A fluvoxamine-caffeine interaction study. · 1996 · https://pubmed.ncbi.nlm.nih.gov/8807660/ · DOI 10.1097/00008571-199606000-00003
Complete structured claim and evidence
Caffeine N7-demethylation produced the specified dimethylxanthine; fluvoxamine reduced its formation clearance.
Caffeine → Theophylline source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Human caffeine/fluvoxamine crossover and metabolite measurements; eight healthy volunteers.
limitations
CYP1A2 is the principal demethylating route; minor routes and individual clearance vary.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Caffeine produces a distinct metabolite that needs its own record.
primary_references
A fluvoxamine-caffeine interaction study. · 1996 · https://pubmed.ncbi.nlm.nih.gov/8807660/ · DOI 10.1097/00008571-199606000-00003
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 188–194
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Human caffeine/fluvoxamine crossover and metabolite measurements; eight healthy volunteers. · source_derived_draft · unverified_draft
## caf-met-tp Caffeine produces a distinct metabolite that needs its own record. Caffeine N7-demethylation produced the specified dimethylxanthine; fluvoxamine reduced its formation clearance. Model: Human caffeine/fluvoxamine crossover and metabolite measurements; eight healthy volunteers. Limitations: CYP1A2 is the principal demethylating route; minor routes and individual clearance vary. Evidence access: Primary abstract A fluvoxamine-caffeine interaction study. · 1996 · https://pubmed.ncbi.nlm.nih.gov/8807660/ · DOI 10.1097/00008571-199606000-00003
Complete structured claim and evidence
Median caffeine clearance fell from 107 to 21 mL/min during fluvoxamine treatment.
Fluvoxamine → Caffeine clearance source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Human caffeine/fluvoxamine crossover and metabolite measurements; eight healthy volunteers.
limitations
Study used 200 mg caffeine and repeated fluvoxamine; not a prediction of the same effect size for every CYP1A2 inhibitor.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Inhibiting the metabolic pathway slowed caffeine removal.
primary_references
A fluvoxamine-caffeine interaction study. · 1996 · https://pubmed.ncbi.nlm.nih.gov/8807660/ · DOI 10.1097/00008571-199606000-00003
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 196–202
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Human caffeine/fluvoxamine crossover and metabolite measurements; eight healthy volunteers. · source_derived_draft · unverified_draft
## caf-fluvox-clear Inhibiting the metabolic pathway slowed caffeine removal. Median caffeine clearance fell from 107 to 21 mL/min during fluvoxamine treatment. Model: Human caffeine/fluvoxamine crossover and metabolite measurements; eight healthy volunteers. Limitations: Study used 200 mg caffeine and repeated fluvoxamine; not a prediction of the same effect size for every CYP1A2 inhibitor. Evidence access: Primary abstract A fluvoxamine-caffeine interaction study. · 1996 · https://pubmed.ncbi.nlm.nih.gov/8807660/ · DOI 10.1097/00008571-199606000-00003
Complete structured claim and evidence
Caffeine half-life increased from five to 31 hours in the fluvoxamine crossover experiment.
Fluvoxamine → Caffeine elimination half-life source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Human caffeine/fluvoxamine crossover and metabolite measurements; eight healthy volunteers.
limitations
Reported median under this regimen, not a universal caffeine half-life.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
The same dose remained in the body much longer.
primary_references
A fluvoxamine-caffeine interaction study. · 1996 · https://pubmed.ncbi.nlm.nih.gov/8807660/ · DOI 10.1097/00008571-199606000-00003
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 204–210
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Human caffeine/fluvoxamine crossover and metabolite measurements; eight healthy volunteers. · source_derived_draft · unverified_draft
## caf-fluvox-half The same dose remained in the body much longer. Caffeine half-life increased from five to 31 hours in the fluvoxamine crossover experiment. Model: Human caffeine/fluvoxamine crossover and metabolite measurements; eight healthy volunteers. Limitations: Reported median under this regimen, not a universal caffeine half-life. Evidence access: Primary abstract A fluvoxamine-caffeine interaction study. · 1996 · https://pubmed.ncbi.nlm.nih.gov/8807660/ · DOI 10.1097/00008571-199606000-00003
Complete structured claim and evidence
In human liver microsomes, fluvoxamine inhibited caffeine demethylated-metabolite formation with Ki values of 0.08–0.28 micromolar.
Fluvoxamine → Human cytochrome P450 1A2 source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Human liver microsomes; metabolite HPLC.
limitations
Not all three demethylations are exclusively CYP1A2-dependent.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
An enzyme experiment supports the observed clearance interaction.
primary_references
Fluvoxamine is a potent inhibitor of the metabolism of caffeine in vitro. · 1998 · https://pubmed.ncbi.nlm.nih.gov/9868741/ · DOI 10.1111/j.1600-0773.1998.tb01476.x
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AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Human liver microsomes; metabolite HPLC. · source_derived_draft · unverified_draft
## caf-cyp1a2-inhibition An enzyme experiment supports the observed clearance interaction. In human liver microsomes, fluvoxamine inhibited caffeine demethylated-metabolite formation with Ki values of 0.08–0.28 micromolar. Model: Human liver microsomes; metabolite HPLC. Limitations: Not all three demethylations are exclusively CYP1A2-dependent. Evidence access: Primary abstract Fluvoxamine is a potent inhibitor of the metabolism of caffeine in vitro. · 1998 · https://pubmed.ncbi.nlm.nih.gov/9868741/ · DOI 10.1111/j.1600-0773.1998.tb01476.x
Complete structured claim and evidence
Inhibitor experiments supported CYP3A4 involvement in caffeine 8-hydroxylation to trimethyluric acid.
Human cytochrome P450 3A4 → 1,3,7-Trimethyluric acid source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Human liver microsomes with ketoconazole and bromocriptine.
limitations
Enzyme attribution was pharmacological, not a single-enzyme knockout.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
A minor oxidative branch differs from demethylation.
primary_references
Fluvoxamine is a potent inhibitor of the metabolism of caffeine in vitro. · 1998 · https://pubmed.ncbi.nlm.nih.gov/9868741/ · DOI 10.1111/j.1600-0773.1998.tb01476.x
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 220–226
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Human liver microsomes with ketoconazole and bromocriptine. · source_derived_draft · unverified_draft
## caf-cyp3a4 A minor oxidative branch differs from demethylation. Inhibitor experiments supported CYP3A4 involvement in caffeine 8-hydroxylation to trimethyluric acid. Model: Human liver microsomes with ketoconazole and bromocriptine. Limitations: Enzyme attribution was pharmacological, not a single-enzyme knockout. Evidence access: Primary abstract Fluvoxamine is a potent inhibitor of the metabolism of caffeine in vitro. · 1998 · https://pubmed.ncbi.nlm.nih.gov/9868741/ · DOI 10.1111/j.1600-0773.1998.tb01476.x
Complete structured claim and evidence
Allopurinol specifically and dose-dependently inhibited conversion of caffeine-derived 1-methylxanthine to 1-methyluric acid.
1-Methylxanthine → 1-Methyluric acid source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Two healthy nonsmokers; caffeine 5 mg/kg before/during allopurinol 300 or 600 mg/day.
limitations
Very small human mechanistic study; not proof that dietary molybdenum controls parent-caffeine clearance.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
A later caffeine metabolite uses the xanthine-oxidoreductase pathway.
primary_references
Effect of allopurinol on caffeine disposition in man. · 1986 · https://pubmed.ncbi.nlm.nih.gov/3754760/ · DOI 10.1111/j.1365-2125.1986.tb05222.x
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 228–234
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Two healthy nonsmokers; caffeine 5 mg/kg before/during allopurinol 300 or 600 mg/day. · source_derived_draft · unverified_draft
## caf-xor-product A later caffeine metabolite uses the xanthine-oxidoreductase pathway. Allopurinol specifically and dose-dependently inhibited conversion of caffeine-derived 1-methylxanthine to 1-methyluric acid. Model: Two healthy nonsmokers; caffeine 5 mg/kg before/during allopurinol 300 or 600 mg/day. Limitations: Very small human mechanistic study; not proof that dietary molybdenum controls parent-caffeine clearance. Evidence access: Primary abstract Effect of allopurinol on caffeine disposition in man. · 1986 · https://pubmed.ncbi.nlm.nih.gov/3754760/ · DOI 10.1111/j.1365-2125.1986.tb05222.x
Complete structured claim and evidence
In 21 participants, allopurinol reduced urinary 1-methyluric-acid/1-methylxanthine to 15.9% of baseline.
Allopurinol → Caffeine-derived urinary enzyme-phenotyping ratios source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
200 mg caffeine tests during allopurinol 300 mg/day for eight days.
limitations
The ratio is a context-dependent probe, not a direct measurement of dietary molybdenum.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Blocking a downstream enzyme changed the metabolite pattern.
primary_references
Xanthine oxidase inhibition by allopurinol affects the reliability of urinary caffeine metabolic ratios as markers for N-acetyltransferase 2 and CYP1A2 activities. · 1999 · https://pubmed.ncbi.nlm.nih.gov/10027663/ · DOI 10.1007/s002280050569
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 236–242
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · 200 mg caffeine tests during allopurinol 300 mg/day for eight days. · source_derived_draft · unverified_draft
## caf-xor-ratio Blocking a downstream enzyme changed the metabolite pattern. In 21 participants, allopurinol reduced urinary 1-methyluric-acid/1-methylxanthine to 15.9% of baseline. Model: 200 mg caffeine tests during allopurinol 300 mg/day for eight days. Limitations: The ratio is a context-dependent probe, not a direct measurement of dietary molybdenum. Evidence access: Primary abstract Xanthine oxidase inhibition by allopurinol affects the reliability of urinary caffeine metabolic ratios as markers for N-acetyltransferase 2 and CYP1A2 activities. · 1999 · https://pubmed.ncbi.nlm.nih.gov/10027663/ · DOI 10.1007/s002280050569
Complete structured claim and evidence
The NAT2 ratio AFMU/1MX fell to 56.7%, an alternative combined-metabolite NAT2 ratio stayed constant, and a CYP1A2 ratio transiently rose to 167%.
Allopurinol → Caffeine-derived urinary enzyme-phenotyping ratios source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Same 21-person caffeine-phenotyping study.
limitations
Changed ratios do not prove corresponding changes in NAT2 or CYP1A2 catalytic activity.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
A downstream block can make another enzyme’s probe result misleading.
primary_references
Xanthine oxidase inhibition by allopurinol affects the reliability of urinary caffeine metabolic ratios as markers for N-acetyltransferase 2 and CYP1A2 activities. · 1999 · https://pubmed.ncbi.nlm.nih.gov/10027663/ · DOI 10.1007/s002280050569
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AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Same 21-person caffeine-phenotyping study. · source_derived_draft · unverified_draft
## caf-probe-confounding A downstream block can make another enzyme’s probe result misleading. The NAT2 ratio AFMU/1MX fell to 56.7%, an alternative combined-metabolite NAT2 ratio stayed constant, and a CYP1A2 ratio transiently rose to 167%. Model: Same 21-person caffeine-phenotyping study. Limitations: Changed ratios do not prove corresponding changes in NAT2 or CYP1A2 catalytic activity. Evidence access: Primary abstract Xanthine oxidase inhibition by allopurinol affects the reliability of urinary caffeine metabolic ratios as markers for N-acetyltransferase 2 and CYP1A2 activities. · 1999 · https://pubmed.ncbi.nlm.nih.gov/10027663/ · DOI 10.1007/s002280050569
Complete structured claim and evidence
Women using oral contraceptives had caffeine half-life 10.7 versus 6.2 hours and lower clearance than women not using them.
Oral contraceptive steroids, study-specific formulations → Caffeine elimination half-life source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
250 mg caffeine; nine women per female group and 13 men; historical formulations.
limitations
Between-group study and formulation-specific context; no universal effect size for all contraceptives.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Hormonal medication changed caffeine persistence.
primary_references
Impaired elimination of caffeine by oral contraceptive steroids. · 1980 · https://pubmed.ncbi.nlm.nih.gov/7359014/
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 252–258
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · 250 mg caffeine; nine women per female group and 13 men; historical formulations. · source_derived_draft · unverified_draft
## caf-contraceptive Hormonal medication changed caffeine persistence. Women using oral contraceptives had caffeine half-life 10.7 versus 6.2 hours and lower clearance than women not using them. Model: 250 mg caffeine; nine women per female group and 13 men; historical formulations. Limitations: Between-group study and formulation-specific context; no universal effect size for all contraceptives. Evidence access: Primary abstract Impaired elimination of caffeine by oral contraceptive steroids. · 1980 · https://pubmed.ncbi.nlm.nih.gov/7359014/
Complete structured claim and evidence
Dose-normalized serum caffeine rose between first and third trimester in a 59-woman study; theophylline concentrations also rose.
Caffeine → Plasma caffeine exposure source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Women sampled once during a trimester, within one hour of a beverage containing 30–95 mg caffeine.
limitations
Sparse, between-person sampling; not full individual clearance curves or evidence establishing fetal safety.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Pregnancy changed caffeine and metabolite exposure.
primary_references
Pregnancy-induced changes in the pharmacokinetics of caffeine and its metabolites. · 2016 · https://pubmed.ncbi.nlm.nih.gov/26358647/ · DOI 10.1002/jcph.632
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 260–266
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Women sampled once during a trimester, within one hour of a beverage containing 30–95 mg caffeine. · source_derived_draft · unverified_draft
## caf-pregnancy Pregnancy changed caffeine and metabolite exposure. Dose-normalized serum caffeine rose between first and third trimester in a 59-woman study; theophylline concentrations also rose. Model: Women sampled once during a trimester, within one hour of a beverage containing 30–95 mg caffeine. Limitations: Sparse, between-person sampling; not full individual clearance curves or evidence establishing fetal safety. Evidence access: Primary abstract Pregnancy-induced changes in the pharmacokinetics of caffeine and its metabolites. · 2016 · https://pubmed.ncbi.nlm.nih.gov/26358647/ · DOI 10.1002/jcph.632
Complete structured claim and evidence
Caffeine coadministration increased mean clozapine AUC by 19% in the crossover experiment.
Caffeine → Plasma clozapine exposure source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
12 nonsmoking healthy men; single 12.5 mg clozapine; caffeine 400–1000 mg/day, mean 550.
limitations
Small healthy-volunteer study; patient effect size and toxicity cannot be inferred for an individual.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Caffeine changed exposure to a drug sharing its metabolic pathway.
primary_references
Effect of caffeine on clozapine pharmacokinetics in healthy volunteers. · 2000 · https://pubmed.ncbi.nlm.nih.gov/10606838/ · DOI 10.1046/j.1365-2125.2000.00111.x
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 268–274
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · 12 nonsmoking healthy men; single 12.5 mg clozapine; caffeine 400–1000 mg/day, mean 550. · source_derived_draft · unverified_draft
## caf-clozapine-auc Caffeine changed exposure to a drug sharing its metabolic pathway. Caffeine coadministration increased mean clozapine AUC by 19% in the crossover experiment. Model: 12 nonsmoking healthy men; single 12.5 mg clozapine; caffeine 400–1000 mg/day, mean 550. Limitations: Small healthy-volunteer study; patient effect size and toxicity cannot be inferred for an individual. Evidence access: Primary abstract Effect of caffeine on clozapine pharmacokinetics in healthy volunteers. · 2000 · https://pubmed.ncbi.nlm.nih.gov/10606838/ · DOI 10.1046/j.1365-2125.2000.00111.x
Complete structured claim and evidence
Mean clozapine oral clearance fell 14%; metabolite-to-parent ratios also fell during caffeine exposure.
Caffeine → Clozapine oral clearance source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Same randomized open-label crossover.
limitations
Not a medication-adjustment rule.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
The pharmacokinetic pattern supported reduced drug metabolism.
primary_references
Effect of caffeine on clozapine pharmacokinetics in healthy volunteers. · 2000 · https://pubmed.ncbi.nlm.nih.gov/10606838/ · DOI 10.1046/j.1365-2125.2000.00111.x
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 276–282
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Same randomized open-label crossover. · source_derived_draft · unverified_draft
## caf-clozapine-clear The pharmacokinetic pattern supported reduced drug metabolism. Mean clozapine oral clearance fell 14%; metabolite-to-parent ratios also fell during caffeine exposure. Model: Same randomized open-label crossover. Limitations: Not a medication-adjustment rule. Evidence access: Primary abstract Effect of caffeine on clozapine pharmacokinetics in healthy volunteers. · 2000 · https://pubmed.ncbi.nlm.nih.gov/10606838/ · DOI 10.1046/j.1365-2125.2000.00111.x
Complete structured claim and evidence
Calcium reabsorption fell from 98.6% to 97.5%, with no significant change in filtered calcium load.
Caffeine → Renal calcium reabsorption source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
37 women, age 31–78; decaffeinated beverage with or without caffeine 6 mg/kg lean body mass; two-hour urine collection.
limitations
Acute renal handling. The exact tubular mechanism was unresolved; no long-term deficiency, bone loss or replacement requirement measured.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
The kidneys retained a smaller fraction of the filtered mineral.
primary_references
Effects of dietary caffeine on renal handling of minerals in adult women. · 1990 · https://pubmed.ncbi.nlm.nih.gov/2402180/ · DOI 10.1016/0024-3205(90)90616-y
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 284–290
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · 37 women, age 31–78; decaffeinated beverage with or without caffeine 6 mg/kg lean body mass; two-hour urine collection. · source_derived_draft · unverified_draft
## caf-renal-ca The kidneys retained a smaller fraction of the filtered mineral. Calcium reabsorption fell from 98.6% to 97.5%, with no significant change in filtered calcium load. Model: 37 women, age 31–78; decaffeinated beverage with or without caffeine 6 mg/kg lean body mass; two-hour urine collection. Limitations: Acute renal handling. The exact tubular mechanism was unresolved; no long-term deficiency, bone loss or replacement requirement measured. Evidence access: Primary abstract Effects of dietary caffeine on renal handling of minerals in adult women. · 1990 · https://pubmed.ncbi.nlm.nih.gov/2402180/ · DOI 10.1016/0024-3205(90)90616-y
Complete structured claim and evidence
Magnesium reabsorption fell from 97.0% to 94.2%, with no significant change in filtered magnesium load.
Caffeine → Renal magnesium reabsorption source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
37 women, age 31–78; decaffeinated beverage with or without caffeine 6 mg/kg lean body mass; two-hour urine collection.
limitations
Acute renal handling. The exact tubular mechanism was unresolved; no long-term deficiency, bone loss or replacement requirement measured.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
The kidneys retained a smaller fraction of the filtered mineral.
primary_references
Effects of dietary caffeine on renal handling of minerals in adult women. · 1990 · https://pubmed.ncbi.nlm.nih.gov/2402180/ · DOI 10.1016/0024-3205(90)90616-y
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 292–298
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · 37 women, age 31–78; decaffeinated beverage with or without caffeine 6 mg/kg lean body mass; two-hour urine collection. · source_derived_draft · unverified_draft
## caf-renal-mg The kidneys retained a smaller fraction of the filtered mineral. Magnesium reabsorption fell from 97.0% to 94.2%, with no significant change in filtered magnesium load. Model: 37 women, age 31–78; decaffeinated beverage with or without caffeine 6 mg/kg lean body mass; two-hour urine collection. Limitations: Acute renal handling. The exact tubular mechanism was unresolved; no long-term deficiency, bone loss or replacement requirement measured. Evidence access: Primary abstract Effects of dietary caffeine on renal handling of minerals in adult women. · 1990 · https://pubmed.ncbi.nlm.nih.gov/2402180/ · DOI 10.1016/0024-3205(90)90616-y
Complete structured claim and evidence
Urinary calcium/creatinine rose from 120 to 200 mg/g.
Caffeine → Urinary calcium excretion source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
37 women, age 31–78; decaffeinated beverage with or without caffeine 6 mg/kg lean body mass; two-hour urine collection.
limitations
Acute renal handling. The exact tubular mechanism was unresolved; no long-term deficiency, bone loss or replacement requirement measured.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
The acute urine measurement increased.
primary_references
Effects of dietary caffeine on renal handling of minerals in adult women. · 1990 · https://pubmed.ncbi.nlm.nih.gov/2402180/ · DOI 10.1016/0024-3205(90)90616-y
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 300–306
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · 37 women, age 31–78; decaffeinated beverage with or without caffeine 6 mg/kg lean body mass; two-hour urine collection. · source_derived_draft · unverified_draft
## caf-urine-ca The acute urine measurement increased. Urinary calcium/creatinine rose from 120 to 200 mg/g. Model: 37 women, age 31–78; decaffeinated beverage with or without caffeine 6 mg/kg lean body mass; two-hour urine collection. Limitations: Acute renal handling. The exact tubular mechanism was unresolved; no long-term deficiency, bone loss or replacement requirement measured. Evidence access: Primary abstract Effects of dietary caffeine on renal handling of minerals in adult women. · 1990 · https://pubmed.ncbi.nlm.nih.gov/2402180/ · DOI 10.1016/0024-3205(90)90616-y
Complete structured claim and evidence
Urinary magnesium/creatinine rose from 70 to 110 mg/g.
Caffeine → Urinary magnesium excretion source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
37 women, age 31–78; decaffeinated beverage with or without caffeine 6 mg/kg lean body mass; two-hour urine collection.
limitations
Acute renal handling. The exact tubular mechanism was unresolved; no long-term deficiency, bone loss or replacement requirement measured.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
The acute urine measurement increased.
primary_references
Effects of dietary caffeine on renal handling of minerals in adult women. · 1990 · https://pubmed.ncbi.nlm.nih.gov/2402180/ · DOI 10.1016/0024-3205(90)90616-y
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 308–314
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · 37 women, age 31–78; decaffeinated beverage with or without caffeine 6 mg/kg lean body mass; two-hour urine collection. · source_derived_draft · unverified_draft
## caf-urine-mg The acute urine measurement increased. Urinary magnesium/creatinine rose from 70 to 110 mg/g. Model: 37 women, age 31–78; decaffeinated beverage with or without caffeine 6 mg/kg lean body mass; two-hour urine collection. Limitations: Acute renal handling. The exact tubular mechanism was unresolved; no long-term deficiency, bone loss or replacement requirement measured. Evidence access: Primary abstract Effects of dietary caffeine on renal handling of minerals in adult women. · 1990 · https://pubmed.ncbi.nlm.nih.gov/2402180/ · DOI 10.1016/0024-3205(90)90616-y
Complete structured claim and evidence
Urinary sodium/creatinine rose from 3800 to 6200 mg/g.
Caffeine → Urinary sodium excretion source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
37 women, age 31–78; decaffeinated beverage with or without caffeine 6 mg/kg lean body mass; two-hour urine collection.
limitations
Acute renal handling. The exact tubular mechanism was unresolved; no long-term deficiency, bone loss or replacement requirement measured.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
The acute urine measurement increased.
primary_references
Effects of dietary caffeine on renal handling of minerals in adult women. · 1990 · https://pubmed.ncbi.nlm.nih.gov/2402180/ · DOI 10.1016/0024-3205(90)90616-y
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 316–322
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · 37 women, age 31–78; decaffeinated beverage with or without caffeine 6 mg/kg lean body mass; two-hour urine collection. · source_derived_draft · unverified_draft
## caf-urine-na The acute urine measurement increased. Urinary sodium/creatinine rose from 3800 to 6200 mg/g. Model: 37 women, age 31–78; decaffeinated beverage with or without caffeine 6 mg/kg lean body mass; two-hour urine collection. Limitations: Acute renal handling. The exact tubular mechanism was unresolved; no long-term deficiency, bone loss or replacement requirement measured. Evidence access: Primary abstract Effects of dietary caffeine on renal handling of minerals in adult women. · 1990 · https://pubmed.ncbi.nlm.nih.gov/2402180/ · DOI 10.1016/0024-3205(90)90616-y
Complete structured claim and evidence
Urinary chloride/creatinine rose from 9200 to 14800 mg/g.
Caffeine → Urinary chloride excretion source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
37 women, age 31–78; decaffeinated beverage with or without caffeine 6 mg/kg lean body mass; two-hour urine collection.
limitations
Acute renal handling. The exact tubular mechanism was unresolved; no long-term deficiency, bone loss or replacement requirement measured.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
The acute urine measurement increased.
primary_references
Effects of dietary caffeine on renal handling of minerals in adult women. · 1990 · https://pubmed.ncbi.nlm.nih.gov/2402180/ · DOI 10.1016/0024-3205(90)90616-y
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 324–330
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · 37 women, age 31–78; decaffeinated beverage with or without caffeine 6 mg/kg lean body mass; two-hour urine collection. · source_derived_draft · unverified_draft
## caf-urine-cl The acute urine measurement increased. Urinary chloride/creatinine rose from 9200 to 14800 mg/g. Model: 37 women, age 31–78; decaffeinated beverage with or without caffeine 6 mg/kg lean body mass; two-hour urine collection. Limitations: Acute renal handling. The exact tubular mechanism was unresolved; no long-term deficiency, bone loss or replacement requirement measured. Evidence access: Primary abstract Effects of dietary caffeine on renal handling of minerals in adult women. · 1990 · https://pubmed.ncbi.nlm.nih.gov/2402180/ · DOI 10.1016/0024-3205(90)90616-y
Complete structured claim and evidence
Total potassium output increased over the two-hour post-caffeine collection.
Caffeine → Urinary potassium excretion source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
37 women, age 31–78; decaffeinated beverage with or without caffeine 6 mg/kg lean body mass; two-hour urine collection.
limitations
The abstract did not report a significant potassium/creatinine ratio change; total output must not be confused with selective potassium wasting.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Potassium output also changed in the short collection.
primary_references
Effects of dietary caffeine on renal handling of minerals in adult women. · 1990 · https://pubmed.ncbi.nlm.nih.gov/2402180/ · DOI 10.1016/0024-3205(90)90616-y
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 332–338
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · 37 women, age 31–78; decaffeinated beverage with or without caffeine 6 mg/kg lean body mass; two-hour urine collection. · source_derived_draft · unverified_draft
## caf-urine-k Potassium output also changed in the short collection. Total potassium output increased over the two-hour post-caffeine collection. Model: 37 women, age 31–78; decaffeinated beverage with or without caffeine 6 mg/kg lean body mass; two-hour urine collection. Limitations: The abstract did not report a significant potassium/creatinine ratio change; total output must not be confused with selective potassium wasting. Evidence access: Primary abstract Effects of dietary caffeine on renal handling of minerals in adult women. · 1990 · https://pubmed.ncbi.nlm.nih.gov/2402180/ · DOI 10.1016/0024-3205(90)90616-y
Complete structured claim and evidence
Later nighttime conservation did not fully offset earlier loss; net 24-hour urinary excretion increased by 0.32 mmol.
Caffeine → Urinary calcium excretion source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
17 adults; controlled diet; two 3 mg/kg lean-body-mass doses on day two of a before/after metabolic-ward trial.
limitations
Two-day urinary balance is not total body mineral balance or a long-term deficiency diagnosis.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Later compensation reduced, but did not erase, the measured daily loss.
primary_references
Effect of caffeine on circadian excretion of urinary calcium and magnesium. · 1994 · https://pubmed.ncbi.nlm.nih.gov/7836625/ · DOI 10.1080/07315724.1994.10718436
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 340–346
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · 17 adults; controlled diet; two 3 mg/kg lean-body-mass doses on day two of a before/after metabolic-ward trial. · source_derived_draft · unverified_draft
## caf-ca24 Later compensation reduced, but did not erase, the measured daily loss. Later nighttime conservation did not fully offset earlier loss; net 24-hour urinary excretion increased by 0.32 mmol. Model: 17 adults; controlled diet; two 3 mg/kg lean-body-mass doses on day two of a before/after metabolic-ward trial. Limitations: Two-day urinary balance is not total body mineral balance or a long-term deficiency diagnosis. Evidence access: Primary abstract Effect of caffeine on circadian excretion of urinary calcium and magnesium. · 1994 · https://pubmed.ncbi.nlm.nih.gov/7836625/ · DOI 10.1080/07315724.1994.10718436
Complete structured claim and evidence
Later nighttime conservation did not fully offset earlier loss; net 24-hour urinary excretion increased by 0.16 mmol.
Caffeine → Urinary magnesium excretion source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
17 adults; controlled diet; two 3 mg/kg lean-body-mass doses on day two of a before/after metabolic-ward trial.
limitations
Two-day urinary balance is not total body mineral balance or a long-term deficiency diagnosis.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Later compensation reduced, but did not erase, the measured daily loss.
primary_references
Effect of caffeine on circadian excretion of urinary calcium and magnesium. · 1994 · https://pubmed.ncbi.nlm.nih.gov/7836625/ · DOI 10.1080/07315724.1994.10718436
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 348–354
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · 17 adults; controlled diet; two 3 mg/kg lean-body-mass doses on day two of a before/after metabolic-ward trial. · source_derived_draft · unverified_draft
## caf-mg24 Later compensation reduced, but did not erase, the measured daily loss. Later nighttime conservation did not fully offset earlier loss; net 24-hour urinary excretion increased by 0.16 mmol. Model: 17 adults; controlled diet; two 3 mg/kg lean-body-mass doses on day two of a before/after metabolic-ward trial. Limitations: Two-day urinary balance is not total body mineral balance or a long-term deficiency diagnosis. Evidence access: Primary abstract Effect of caffeine on circadian excretion of urinary calcium and magnesium. · 1994 · https://pubmed.ncbi.nlm.nih.gov/7836625/ · DOI 10.1080/07315724.1994.10718436
Complete structured claim and evidence
An 800 mg total caffeine gum regimen increased renal calcium clearance by 77%; changes correlated with sodium clearance and urine volume.
Caffeine → Renal calcium clearance source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Double-blind study, 12 caffeine and 12 placebo participants over six hours.
limitations
Proximal sodium-reabsorption inhibition was proposed from correlations, not directly measured; no osteoporosis outcome.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
High repeated exposure changed renal calcium clearance.
primary_references
The effect of high-dose, short-term caffeine intake on the renal clearance of calcium, sodium and creatinine in healthy adults. · 2021 · https://pubmed.ncbi.nlm.nih.gov/33852164/ · DOI 10.1111/bcp.14856
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 356–362
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Double-blind study, 12 caffeine and 12 placebo participants over six hours. · source_derived_draft · unverified_draft
## caf-high-calcium High repeated exposure changed renal calcium clearance. An 800 mg total caffeine gum regimen increased renal calcium clearance by 77%; changes correlated with sodium clearance and urine volume. Model: Double-blind study, 12 caffeine and 12 placebo participants over six hours. Limitations: Proximal sodium-reabsorption inhibition was proposed from correlations, not directly measured; no osteoporosis outcome. Evidence access: Primary abstract The effect of high-dose, short-term caffeine intake on the renal clearance of calcium, sodium and creatinine in healthy adults. · 2021 · https://pubmed.ncbi.nlm.nih.gov/33852164/ · DOI 10.1111/bcp.14856
Complete structured claim and evidence
Caffeine 45 mg/kg caused diuresis and natriuresis in wild-type but not A1-knockout mice.
Mouse adenosine A1 receptor / Adora1 → Urinary sodium excretion source_derived_draftungraded
Experimental context and source evidence
availability_state
machinery_impairment Imported condition classification; unverified.
evidence_access
Primary abstract
experimental_model
Awake mice; oral gavage and three-hour collection.
limitations
Evidence of receptor dependence, not a directly demonstrated human tubular segment.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Removing A1 receptors removed the renal response in this animal model.
primary_references
Requirement of intact adenosine A1 receptors for the diuretic and natriuretic action of the methylxanthines theophylline and caffeine. · 2005 · https://pubmed.ncbi.nlm.nih.gov/15590766/ · DOI 10.1124/jpet.104.080432
trigger_kind
machinery_impairment Imported condition classification; unverified.
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 364–370
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Awake mice; oral gavage and three-hour collection. · source_derived_draft · unverified_draft
## caf-renal-a1 Removing A1 receptors removed the renal response in this animal model. Caffeine 45 mg/kg caused diuresis and natriuresis in wild-type but not A1-knockout mice. Model: Awake mice; oral gavage and three-hour collection. Limitations: Evidence of receptor dependence, not a directly demonstrated human tubular segment. Evidence access: Primary abstract Requirement of intact adenosine A1 receptors for the diuretic and natriuretic action of the methylxanthines theophylline and caffeine. · 2005 · https://pubmed.ncbi.nlm.nih.gov/15590766/ · DOI 10.1124/jpet.104.080432
Complete structured claim and evidence
In 50 habitual male coffee drinkers, coffee and water produced no significant difference in total body water or 24-hour urine volume.
Coffee beverage, study-specific mixture → Total body water source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Three-day crossover; four 200 mL servings supplying 4 mg/kg/day caffeine versus equal water.
limitations
Whole coffee plus fluid in habituated men, not dry caffeine or an acute bolus in nonusers.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
An acute diuretic effect does not mean habitual coffee drinking always dehydrates.
primary_references
No evidence of dehydration with moderate daily coffee intake: a counterbalanced cross-over study in a free-living population. · 2014 · https://pubmed.ncbi.nlm.nih.gov/24416202/ · DOI 10.1371/journal.pone.0084154
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 372–378
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Three-day crossover; four 200 mL servings supplying 4 mg/kg/day caffeine versus equal water. · source_derived_draft · unverified_draft
## caf-coffee-water An acute diuretic effect does not mean habitual coffee drinking always dehydrates. In 50 habitual male coffee drinkers, coffee and water produced no significant difference in total body water or 24-hour urine volume. Model: Three-day crossover; four 200 mL servings supplying 4 mg/kg/day caffeine versus equal water. Limitations: Whole coffee plus fluid in habituated men, not dry caffeine or an acute bolus in nonusers. Evidence access: Primary abstract No evidence of dehydration with moderate daily coffee intake: a counterbalanced cross-over study in a free-living population. · 2014 · https://pubmed.ncbi.nlm.nih.gov/24416202/ · DOI 10.1371/journal.pone.0084154
Complete structured claim and evidence
Millimolar caffeine activated the skeletal-muscle ryanodine-receptor system; xanthine substitution altered ryanodine binding.
Caffeine → Rabbit skeletal-muscle ryanodine receptor 1 / Ryr1 source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Rabbit skeletal-muscle sarcoplasmic-reticulum vesicles; structure–activity comparison.
limitations
Millimolar preparation effects must not be presented as the mechanism of every ordinary caffeinated drink.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
At high experimental concentrations caffeine affects calcium-release machinery.
primary_references
Structure-activity relationship of xanthines and skeletal muscle ryanodine receptor/Ca2+ release channel. · 1997 · https://pubmed.ncbi.nlm.nih.gov/9127436/ · DOI 10.1159/000139480
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 380–386
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Rabbit skeletal-muscle sarcoplasmic-reticulum vesicles; structure–activity comparison. · source_derived_draft · unverified_draft
## caf-ryr At high experimental concentrations caffeine affects calcium-release machinery. Millimolar caffeine activated the skeletal-muscle ryanodine-receptor system; xanthine substitution altered ryanodine binding. Model: Rabbit skeletal-muscle sarcoplasmic-reticulum vesicles; structure–activity comparison. Limitations: Millimolar preparation effects must not be presented as the mechanism of every ordinary caffeinated drink. Evidence access: Primary abstract Structure-activity relationship of xanthines and skeletal muscle ryanodine receptor/Ca2+ release channel. · 1997 · https://pubmed.ncbi.nlm.nih.gov/9127436/ · DOI 10.1159/000139480
Complete structured claim and evidence
Caffeine inhibited IP3-gated channels with half-inhibition at 1.64 mM; 5 mM reduced opening frequency more than threefold without changing conductance.
Caffeine → Canine cerebellar IP3-gated calcium channel preparation source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Canine cerebellar channels in planar lipid bilayers.
limitations
Millimolar concentrations; opposite channel effects are distinct targets, not a scientific contradiction.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Caffeine can inhibit one calcium-release channel while activating another.
primary_references
Caffeine-induced inhibition of inositol(1,4,5)-trisphosphate-gated calcium channels from cerebellum. · 1994 · https://pubmed.ncbi.nlm.nih.gov/8186468/ · DOI 10.1091/mbc.5.1.97
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 388–394
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Canine cerebellar channels in planar lipid bilayers. · source_derived_draft · unverified_draft
## caf-ip3 Caffeine can inhibit one calcium-release channel while activating another. Caffeine inhibited IP3-gated channels with half-inhibition at 1.64 mM; 5 mM reduced opening frequency more than threefold without changing conductance. Model: Canine cerebellar channels in planar lipid bilayers. Limitations: Millimolar concentrations; opposite channel effects are distinct targets, not a scientific contradiction. Evidence access: Primary abstract Caffeine-induced inhibition of inositol(1,4,5)-trisphosphate-gated calcium channels from cerebellum. · 1994 · https://pubmed.ncbi.nlm.nih.gov/8186468/ · DOI 10.1091/mbc.5.1.97
Complete structured claim and evidence
Increasing IP3 overcame inhibition, but caffeine did not reduce specific IP3 binding to the receptor.
Caffeine → IP3-gated intracellular calcium-channel current source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Same canine channel preparation.
limitations
No human brain outcome or dietary inositol rescue was demonstrated.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
The functional block did not simply displace the measured ligand binding.
primary_references
Caffeine-induced inhibition of inositol(1,4,5)-trisphosphate-gated calcium channels from cerebellum. · 1994 · https://pubmed.ncbi.nlm.nih.gov/8186468/ · DOI 10.1091/mbc.5.1.97
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 396–402
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Same canine channel preparation. · source_derived_draft · unverified_draft
## caf-ip3-rescue The functional block did not simply displace the measured ligand binding. Increasing IP3 overcame inhibition, but caffeine did not reduce specific IP3 binding to the receptor. Model: Same canine channel preparation. Limitations: No human brain outcome or dietary inositol rescue was demonstrated. Evidence access: Primary abstract Caffeine-induced inhibition of inositol(1,4,5)-trisphosphate-gated calcium channels from cerebellum. · 1994 · https://pubmed.ncbi.nlm.nih.gov/8186468/ · DOI 10.1091/mbc.5.1.97
Complete structured claim and evidence
Caffeine inhibited measured cAMP-PDE activity by up to about 40% at 250–500 micrograms/mL in the reported assay.
Caffeine → LXFL529L cytosolic cAMP phosphodiesterase preparation, predominantly PDE4 source_derived_draftungraded
Experimental context and source evidence
evidence_access
Full-text methods 2.14 and results 3.2, Figure 3B; Europe PMC PMC5750604
experimental_model
LXFL529L cytosolic preparation, predominantly PDE4; radioactive cAMP assay.
limitations
Mixed preparation, not a pure PDE isoform or evidence of equivalent inhibition after a normal beverage.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
A high-concentration enzyme effect is separate from receptor antagonism.
primary_references
Inhibition of Cyclic Adenosine Monophosphate-Specific Phosphodiesterase by Various Food Plant-Derived Phytotherapeutic Agents. · 2017 · https://pubmed.ncbi.nlm.nih.gov/29113064/ · DOI 10.3390/medicines4040080
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 404–410
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · LXFL529L cytosolic preparation, predominantly PDE4; radioactive cAMP assay. · source_derived_draft · unverified_draft
## caf-pde A high-concentration enzyme effect is separate from receptor antagonism. Caffeine inhibited measured cAMP-PDE activity by up to about 40% at 250–500 micrograms/mL in the reported assay. Model: LXFL529L cytosolic preparation, predominantly PDE4; radioactive cAMP assay. Limitations: Mixed preparation, not a pure PDE isoform or evidence of equivalent inhibition after a normal beverage. Evidence access: Full-text methods 2.14 and results 3.2, Figure 3B; Europe PMC PMC5750604 Inhibition of Cyclic Adenosine Monophosphate-Specific Phosphodiesterase by Various Food Plant-Derived Phytotherapeutic Agents. · 2017 · https://pubmed.ncbi.nlm.nih.gov/29113064/ · DOI 10.3390/medicines4040080
Complete structured claim and evidence
Caffeine inhibited the checkpoint kinase at concentrations associated with experimental radiosensitization.
Caffeine → Human ATM kinase source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Kinase assays and irradiated A549 tumor-cell experiments.
limitations
Pharmacological radiosensitization context; no claim that dietary caffeine inhibits human DNA repair or treats cancer.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Caffeine also has a laboratory DNA-damage-response target.
primary_references
Inhibition of ATM and ATR kinase activities by the radiosensitizing agent, caffeine. · 1999 · https://pubmed.ncbi.nlm.nih.gov/10485486/
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 412–418
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Kinase assays and irradiated A549 tumor-cell experiments. · source_derived_draft · unverified_draft
## caf-atm Caffeine also has a laboratory DNA-damage-response target. Caffeine inhibited the checkpoint kinase at concentrations associated with experimental radiosensitization. Model: Kinase assays and irradiated A549 tumor-cell experiments. Limitations: Pharmacological radiosensitization context; no claim that dietary caffeine inhibits human DNA repair or treats cancer. Evidence access: Primary abstract Inhibition of ATM and ATR kinase activities by the radiosensitizing agent, caffeine. · 1999 · https://pubmed.ncbi.nlm.nih.gov/10485486/
Complete structured claim and evidence
Caffeine inhibited the checkpoint kinase at concentrations associated with experimental radiosensitization.
Caffeine → Human ATR kinase source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Kinase assays and irradiated A549 tumor-cell experiments.
limitations
Pharmacological radiosensitization context; no claim that dietary caffeine inhibits human DNA repair or treats cancer.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Caffeine also has a laboratory DNA-damage-response target.
primary_references
Inhibition of ATM and ATR kinase activities by the radiosensitizing agent, caffeine. · 1999 · https://pubmed.ncbi.nlm.nih.gov/10485486/
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 420–426
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Kinase assays and irradiated A549 tumor-cell experiments. · source_derived_draft · unverified_draft
## caf-atr Caffeine also has a laboratory DNA-damage-response target. Caffeine inhibited the checkpoint kinase at concentrations associated with experimental radiosensitization. Model: Kinase assays and irradiated A549 tumor-cell experiments. Limitations: Pharmacological radiosensitization context; no claim that dietary caffeine inhibits human DNA repair or treats cancer. Evidence access: Primary abstract Inhibition of ATM and ATR kinase activities by the radiosensitizing agent, caffeine. · 1999 · https://pubmed.ncbi.nlm.nih.gov/10485486/
Complete structured claim and evidence
Caffeine-treated irradiated A549 cells failed G2 arrest and showed radioresistant DNA synthesis after S-phase irradiation.
Caffeine → DNA-damage-induced cell-cycle checkpoint arrest source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Irradiated cultured A549 lung carcinoma cells.
limitations
These findings are not a demonstrated clinical caffeine–radiotherapy benefit.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
The cancer-cell experiment measured altered checkpoint behavior.
primary_references
Inhibition of ATM and ATR kinase activities by the radiosensitizing agent, caffeine. · 1999 · https://pubmed.ncbi.nlm.nih.gov/10485486/
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 428–434
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Irradiated cultured A549 lung carcinoma cells. · source_derived_draft · unverified_draft
## caf-checkpoint The cancer-cell experiment measured altered checkpoint behavior. Caffeine-treated irradiated A549 cells failed G2 arrest and showed radioresistant DNA synthesis after S-phase irradiation. Model: Irradiated cultured A549 lung carcinoma cells. Limitations: These findings are not a demonstrated clinical caffeine–radiotherapy benefit. Evidence access: Primary abstract Inhibition of ATM and ATR kinase activities by the radiosensitizing agent, caffeine. · 1999 · https://pubmed.ncbi.nlm.nih.gov/10485486/
Complete structured claim and evidence
Caffeine reduced radiation-induced p53 Ser15 phosphorylation; DNA-PK was resistant and Chk1 only marginally inhibited in the comparison.
Caffeine → p53 Ser15 phosphorylation source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Kinase and radiation-response assays.
limitations
Do not infer identical activity against all DNA-damage kinases.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
The response was selective across the tested kinase pathways.
primary_references
Inhibition of ATM and ATR kinase activities by the radiosensitizing agent, caffeine. · 1999 · https://pubmed.ncbi.nlm.nih.gov/10485486/
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 436–442
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Kinase and radiation-response assays. · source_derived_draft · unverified_draft
## caf-p53 The response was selective across the tested kinase pathways. Caffeine reduced radiation-induced p53 Ser15 phosphorylation; DNA-PK was resistant and Chk1 only marginally inhibited in the comparison. Model: Kinase and radiation-response assays. Limitations: Do not infer identical activity against all DNA-damage kinases. Evidence access: Primary abstract Inhibition of ATM and ATR kinase activities by the radiosensitizing agent, caffeine. · 1999 · https://pubmed.ncbi.nlm.nih.gov/10485486/
Complete structured claim and evidence
Creatine alone and creatine plus caffeine each increased muscle phosphocreatine by 4–6%; measured ATP stayed constant.
Creatine → Skeletal-muscle phosphocreatine concentration source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Nine healthy men; six-day creatine loading 0.5 g/kg/day, with or without caffeine 5 mg/kg/day; intermittent knee-extensor testing.
limitations
Small protocol-specific trial. Creatine accumulation and performance were separate endpoints.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Caffeine did not block the measured phosphocreatine increase.
primary_references
Caffeine counteracts the ergogenic action of muscle creatine loading. · 1996 · https://pubmed.ncbi.nlm.nih.gov/8929583/ · DOI 10.1152/jappl.1996.80.2.452
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 444–450
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Nine healthy men; six-day creatine loading 0.5 g/kg/day, with or without caffeine 5 mg/kg/day; intermittent knee-extensor testing. · source_derived_draft · unverified_draft
## caf-creatine-pcr Caffeine did not block the measured phosphocreatine increase. Creatine alone and creatine plus caffeine each increased muscle phosphocreatine by 4–6%; measured ATP stayed constant. Model: Nine healthy men; six-day creatine loading 0.5 g/kg/day, with or without caffeine 5 mg/kg/day; intermittent knee-extensor testing. Limitations: Small protocol-specific trial. Creatine accumulation and performance were separate endpoints. Evidence access: Primary abstract Caffeine counteracts the ergogenic action of muscle creatine loading. · 1996 · https://pubmed.ncbi.nlm.nih.gov/8929583/ · DOI 10.1152/jappl.1996.80.2.452
Complete structured claim and evidence
Creatine increased dynamic torque by 10–23%, whereas the creatine-plus-caffeine regimen did not improve torque.
Caffeine → Torque during intermittent knee-extensor exercise source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Nine healthy men; six-day creatine loading 0.5 g/kg/day, with or without caffeine 5 mg/kg/day; intermittent knee-extensor testing.
limitations
Small protocol-specific trial. Creatine accumulation and performance were separate endpoints.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
The same stored-energy increase did not guarantee the same performance response.
primary_references
Caffeine counteracts the ergogenic action of muscle creatine loading. · 1996 · https://pubmed.ncbi.nlm.nih.gov/8929583/ · DOI 10.1152/jappl.1996.80.2.452
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 452–458
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Nine healthy men; six-day creatine loading 0.5 g/kg/day, with or without caffeine 5 mg/kg/day; intermittent knee-extensor testing. · source_derived_draft · unverified_draft
## caf-creatine-torque The same stored-energy increase did not guarantee the same performance response. Creatine increased dynamic torque by 10–23%, whereas the creatine-plus-caffeine regimen did not improve torque. Model: Nine healthy men; six-day creatine loading 0.5 g/kg/day, with or without caffeine 5 mg/kg/day; intermittent knee-extensor testing. Limitations: Small protocol-specific trial. Creatine accumulation and performance were separate endpoints. Evidence access: Primary abstract Caffeine counteracts the ergogenic action of muscle creatine loading. · 1996 · https://pubmed.ncbi.nlm.nih.gov/8929583/ · DOI 10.1152/jappl.1996.80.2.452
Complete structured claim and evidence
Four days of creatine shortened stimulated-muscle relaxation time by about 5%.
Creatine → Electrically evoked quadriceps relaxation time source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Ten men; double-blind crossover; creatine 20 g/day; electrically stimulated quadriceps.
limitations
No direct measurement of calcium-pump mediation.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Creatine altered a muscle-relaxation measurement.
primary_references
Opposite actions of caffeine and creatine on muscle relaxation time in humans. · 2002 · https://pubmed.ncbi.nlm.nih.gov/11796658/ · DOI 10.1152/japplphysiol.00255.2001
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 460–466
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Ten men; double-blind crossover; creatine 20 g/day; electrically stimulated quadriceps. · source_derived_draft · unverified_draft
## caf-relax-creatine Creatine altered a muscle-relaxation measurement. Four days of creatine shortened stimulated-muscle relaxation time by about 5%. Model: Ten men; double-blind crossover; creatine 20 g/day; electrically stimulated quadriceps. Limitations: No direct measurement of calcium-pump mediation. Evidence access: Primary abstract Opposite actions of caffeine and creatine on muscle relaxation time in humans. · 2002 · https://pubmed.ncbi.nlm.nih.gov/11796658/ · DOI 10.1152/japplphysiol.00255.2001
Complete structured claim and evidence
Three days of caffeine 5 mg/kg/day prolonged relaxation time by about 10%; acute caffeine and the creatine/caffeine combination did not significantly change it.
Caffeine → Electrically evoked quadriceps relaxation time source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Same ten-man muscle-stimulation experiment.
limitations
Relaxation is a candidate explanation for performance differences, not proof of a universal creatine interaction.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Repeated and single-dose caffeine did not have the same measured effect.
primary_references
Opposite actions of caffeine and creatine on muscle relaxation time in humans. · 2002 · https://pubmed.ncbi.nlm.nih.gov/11796658/ · DOI 10.1152/japplphysiol.00255.2001
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 468–474
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Same ten-man muscle-stimulation experiment. · source_derived_draft · unverified_draft
## caf-relax-caffeine Repeated and single-dose caffeine did not have the same measured effect. Three days of caffeine 5 mg/kg/day prolonged relaxation time by about 10%; acute caffeine and the creatine/caffeine combination did not significantly change it. Model: Same ten-man muscle-stimulation experiment. Limitations: Relaxation is a candidate explanation for performance differences, not proof of a universal creatine interaction. Evidence access: Primary abstract Opposite actions of caffeine and creatine on muscle relaxation time in humans. · 2002 · https://pubmed.ncbi.nlm.nih.gov/11796658/ · DOI 10.1152/japplphysiol.00255.2001
Complete structured claim and evidence
A single caffeine dose after five days of creatine loading increased mean and peak cycling power over creatine-plus-placebo during sprints 1 and 2.
Caffeine → Power during repeated cycling sprints source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
12 active men; creatine 0.3 g/kg/day followed by caffeine 6 mg/kg; six 10-second sprints.
limitations
Different sequence, task and outcomes from repeated coadministration; not evidence of synergy across all sprints or users.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
A different sequence produced better performance in selected sprints.
primary_references
Effect of caffeine ingestion after creatine supplementation on intermittent high-intensity sprint performance. · 2011 · https://pubmed.ncbi.nlm.nih.gov/21207054/ · DOI 10.1007/s00421-010-1792-0
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 476–482
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · 12 active men; creatine 0.3 g/kg/day followed by caffeine 6 mg/kg; six 10-second sprints. · source_derived_draft · unverified_draft
## caf-postload-caffeine A different sequence produced better performance in selected sprints. A single caffeine dose after five days of creatine loading increased mean and peak cycling power over creatine-plus-placebo during sprints 1 and 2. Model: 12 active men; creatine 0.3 g/kg/day followed by caffeine 6 mg/kg; six 10-second sprints. Limitations: Different sequence, task and outcomes from repeated coadministration; not evidence of synergy across all sprints or users. Evidence access: Primary abstract Effect of caffeine ingestion after creatine supplementation on intermittent high-intensity sprint performance. · 2011 · https://pubmed.ncbi.nlm.nih.gov/21207054/ · DOI 10.1007/s00421-010-1792-0
Complete structured claim and evidence
Caffeine increased plasma epinephrine with or without propranolol.
Caffeine → Plasma epinephrine concentration source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Seven healthy men; 5 mg/kg caffeine, 80 mg propranolol, combination or placebo before an oral glucose tolerance test.
limitations
Small acute experiment. Beta blockade supports an adrenergic contribution, not proof that it is the only mechanism or that a blocker should be used to counter caffeine.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Caffeine changed an adrenergic hormone measurement.
primary_references
Caffeine-induced impairment of glucose tolerance is abolished by beta-adrenergic receptor blockade in humans. · 2002 · https://pubmed.ncbi.nlm.nih.gov/12015346/ · DOI 10.1152/japplphysiol.01229.2001
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 484–490
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Seven healthy men; 5 mg/kg caffeine, 80 mg propranolol, combination or placebo before an oral glucose tolerance test. · source_derived_draft · unverified_draft
## caf-epinephrine Caffeine changed an adrenergic hormone measurement. Caffeine increased plasma epinephrine with or without propranolol. Model: Seven healthy men; 5 mg/kg caffeine, 80 mg propranolol, combination or placebo before an oral glucose tolerance test. Limitations: Small acute experiment. Beta blockade supports an adrenergic contribution, not proof that it is the only mechanism or that a blocker should be used to counter caffeine. Evidence access: Primary abstract Caffeine-induced impairment of glucose tolerance is abolished by beta-adrenergic receptor blockade in humans. · 2002 · https://pubmed.ncbi.nlm.nih.gov/12015346/ · DOI 10.1152/japplphysiol.01229.2001
Complete structured claim and evidence
Insulin and C-peptide areas were 42% and 39% greater with caffeine, while blood glucose was similar among trials.
Caffeine → Insulin response during an oral glucose tolerance test source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Seven healthy men; 5 mg/kg caffeine, 80 mg propranolol, combination or placebo before an oral glucose tolerance test.
limitations
Small acute experiment. Beta blockade supports an adrenergic contribution, not proof that it is the only mechanism or that a blocker should be used to counter caffeine.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
More insulin was measured without a corresponding glucose difference.
primary_references
Caffeine-induced impairment of glucose tolerance is abolished by beta-adrenergic receptor blockade in humans. · 2002 · https://pubmed.ncbi.nlm.nih.gov/12015346/ · DOI 10.1152/japplphysiol.01229.2001
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 492–498
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Seven healthy men; 5 mg/kg caffeine, 80 mg propranolol, combination or placebo before an oral glucose tolerance test. · source_derived_draft · unverified_draft
## caf-insulin More insulin was measured without a corresponding glucose difference. Insulin and C-peptide areas were 42% and 39% greater with caffeine, while blood glucose was similar among trials. Model: Seven healthy men; 5 mg/kg caffeine, 80 mg propranolol, combination or placebo before an oral glucose tolerance test. Limitations: Small acute experiment. Beta blockade supports an adrenergic contribution, not proof that it is the only mechanism or that a blocker should be used to counter caffeine. Evidence access: Primary abstract Caffeine-induced impairment of glucose tolerance is abolished by beta-adrenergic receptor blockade in humans. · 2002 · https://pubmed.ncbi.nlm.nih.gov/12015346/ · DOI 10.1152/japplphysiol.01229.2001
Complete structured claim and evidence
With propranolol, caffeine-associated insulin and C-peptide responses resembled placebo.
Propranolol → Insulin response during an oral glucose tolerance test source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
Seven healthy men; 5 mg/kg caffeine, 80 mg propranolol, combination or placebo before an oral glucose tolerance test.
limitations
Small acute experiment. Beta blockade supports an adrenergic contribution, not proof that it is the only mechanism or that a blocker should be used to counter caffeine.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Blocking beta-adrenergic signaling removed the response in this test.
primary_references
Caffeine-induced impairment of glucose tolerance is abolished by beta-adrenergic receptor blockade in humans. · 2002 · https://pubmed.ncbi.nlm.nih.gov/12015346/ · DOI 10.1152/japplphysiol.01229.2001
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 500–506
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Seven healthy men; 5 mg/kg caffeine, 80 mg propranolol, combination or placebo before an oral glucose tolerance test. · source_derived_draft · unverified_draft
## caf-beta-block Blocking beta-adrenergic signaling removed the response in this test. With propranolol, caffeine-associated insulin and C-peptide responses resembled placebo. Model: Seven healthy men; 5 mg/kg caffeine, 80 mg propranolol, combination or placebo before an oral glucose tolerance test. Limitations: Small acute experiment. Beta blockade supports an adrenergic contribution, not proof that it is the only mechanism or that a blocker should be used to counter caffeine. Evidence access: Primary abstract Caffeine-induced impairment of glucose tolerance is abolished by beta-adrenergic receptor blockade in humans. · 2002 · https://pubmed.ncbi.nlm.nih.gov/12015346/ · DOI 10.1152/japplphysiol.01229.2001
Complete structured claim and evidence
At 36 weeks postmenstrual age, 36% of surviving caffeine-group infants required oxygen versus 47% with placebo; adjusted odds ratio 0.63.
Caffeine citrate → Supplemental oxygen requirement at 36 weeks postmenstrual age source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
CAP randomized trial, 2006 infants weighing 500–1250 g at birth; clinical caffeine-citrate therapy versus placebo.
limitations
Specialist neonatal treatment, not dietary caffeine. Clinical outcomes do not isolate one receptor or prove benefit in other populations.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Clinical caffeine treatment reduced an important neonatal respiratory outcome.
primary_references
Caffeine therapy for apnea of prematurity. · 2006 · https://pubmed.ncbi.nlm.nih.gov/16707748/ · DOI 10.1056/nejmoa054065
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 508–514
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · CAP randomized trial, 2006 infants weighing 500–1250 g at birth; clinical caffeine-citrate therapy versus placebo. · source_derived_draft · unverified_draft
## caf-preterm-oxygen Clinical caffeine treatment reduced an important neonatal respiratory outcome. At 36 weeks postmenstrual age, 36% of surviving caffeine-group infants required oxygen versus 47% with placebo; adjusted odds ratio 0.63. Model: CAP randomized trial, 2006 infants weighing 500–1250 g at birth; clinical caffeine-citrate therapy versus placebo. Limitations: Specialist neonatal treatment, not dietary caffeine. Clinical outcomes do not isolate one receptor or prove benefit in other populations. Evidence access: Primary abstract Caffeine therapy for apnea of prematurity. · 2006 · https://pubmed.ncbi.nlm.nih.gov/16707748/ · DOI 10.1056/nejmoa054065
Complete structured claim and evidence
Positive airway pressure ended at median 31 weeks postmenstrual age versus 32 weeks with placebo.
Caffeine citrate → Duration of positive airway pressure in preterm infants source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
CAP randomized trial, 2006 infants weighing 500–1250 g at birth; clinical caffeine-citrate therapy versus placebo.
limitations
Specialist neonatal treatment, not dietary caffeine. Clinical outcomes do not isolate one receptor or prove benefit in other populations.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
Respiratory support stopped earlier in the treatment group.
primary_references
Caffeine therapy for apnea of prematurity. · 2006 · https://pubmed.ncbi.nlm.nih.gov/16707748/ · DOI 10.1056/nejmoa054065
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 516–522
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · CAP randomized trial, 2006 infants weighing 500–1250 g at birth; clinical caffeine-citrate therapy versus placebo. · source_derived_draft · unverified_draft
## caf-preterm-pressure Respiratory support stopped earlier in the treatment group. Positive airway pressure ended at median 31 weeks postmenstrual age versus 32 weeks with placebo. Model: CAP randomized trial, 2006 infants weighing 500–1250 g at birth; clinical caffeine-citrate therapy versus placebo. Limitations: Specialist neonatal treatment, not dietary caffeine. Clinical outcomes do not isolate one receptor or prove benefit in other populations. Evidence access: Primary abstract Caffeine therapy for apnea of prematurity. · 2006 · https://pubmed.ncbi.nlm.nih.gov/16707748/ · DOI 10.1056/nejmoa054065
Complete structured claim and evidence
Weight gain was temporarily lower, with the greatest mean difference −23 g at two weeks.
Caffeine citrate → Weight gain in preterm infants source_derived_draftungraded
Experimental context and source evidence
evidence_access
Primary abstract
experimental_model
CAP randomized trial, 2006 infants weighing 500–1250 g at birth; clinical caffeine-citrate therapy versus placebo.
limitations
Death, ultrasound brain-injury signs and necrotizing enterocolitis did not differ significantly in this report.
nutrient_topic
Caffeine collection; salts, coffee, species and coexposure contexts retain their identities. · Caffeine
plain_language
The benefit records retain the measured growth tradeoff.
primary_references
Caffeine therapy for apnea of prematurity. · 2006 · https://pubmed.ncbi.nlm.nih.gov/16707748/ · DOI 10.1056/nejmoa054065
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18) · lines 524–530
AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · CAP randomized trial, 2006 infants weighing 500–1250 g at birth; clinical caffeine-citrate therapy versus placebo. · source_derived_draft · unverified_draft
## caf-preterm-growth The benefit records retain the measured growth tradeoff. Weight gain was temporarily lower, with the greatest mean difference −23 g at two weeks. Model: CAP randomized trial, 2006 infants weighing 500–1250 g at birth; clinical caffeine-citrate therapy versus placebo. Limitations: Death, ultrasound brain-injury signs and necrotizing enterocolitis did not differ significantly in this report. Evidence access: Primary abstract Caffeine therapy for apnea of prematurity. · 2006 · https://pubmed.ncbi.nlm.nih.gov/16707748/ · DOI 10.1056/nejmoa054065
Complete structured claim and evidence
Calcium binds an activating RyR1 site and primes gating; ATP and caffeine increase open-state representation in the experimental preparation.
Calcium ion → Ryanodine receptor 1 / RYR1 source_derived_draftungraded
Experimental context and source evidence
compartment_description
Cytosolic channel-regulatory region
experimental_model
Purified rabbit skeletal-muscle RyR1 with calstabin2; cryo-EM and planar-bilayer recordings
limitations
Calcium is both a transported ion and a ligand; caffeine-assisted structures do not imply caffeine is required physiologically.
nutrient_topic
Calcium research collection; topical membership is not evidence of a direct dietary effect. · Calcium
organism
Oryctolagus cuniculus
plain_language
Calcium helps regulate the RyR1 gate.
primary_references
[ca-desgeorges2016] Structural Basis for Gating and Activation of RyR1 (2016). https://pubmed.ncbi.nlm.nih.gov/27662087/ DOI: 10.1016/j.cell.2016.08.075
research_relationship_category
regulation
tissue_or_cell_type
Skeletal-muscle channel preparation
Calcium: mechanism-first literature curation (2026-09-17) · lines 666–677
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified rabbit skeletal-muscle RyR1 with calstabin2; cryo-EM and planar-bilayer recordings · source_derived_draft · unverified_draft
### ca-ryr1-calcium-gating Calcium binds an activating RyR1 site and primes gating; ATP and caffeine increase open-state representation in the experimental preparation. Condition category: normal nutrient_topic: Calcium research collection; topical membership is not evidence of a direct dietary effect. plain_language: Calcium helps regulate the RyR1 gate. organism: Oryctolagus cuniculus tissue_or_cell_type: Skeletal-muscle channel preparation experimental_model: Purified rabbit skeletal-muscle RyR1 with calstabin2; cryo-EM and planar-bilayer recordings limitations: Calcium is both a transported ion and a ligand; caffeine-assisted structures do not imply caffeine is required physiologically. research_relationship_category: regulation compartment_description: Cytosolic channel-regulatory region [ca-desgeorges2016] Structural Basis for Gating and Activation of RyR1 (2016). https://pubmed.ncbi.nlm.nih.gov/27662087/ DOI: 10.1016/j.cell.2016.08.075
Complete structured claim and evidence
Significant inhibition of caffeine-evoked calcium release required 20 µM boric acid in LNCaP cells and 150 µM in non-tumor PWR1E cells.
Boric acid / orthoboric acid / B(OH)3 → Intracellular calcium-store release source_derived_draftungraded
Experimental context and source evidence
evidence_span
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experimental_model
Calcium imaging and flow cytometry in three human prostate cell lines
exposure
Boric acid 1–150 µM depending on agonist and cell line; DU-145 storage assay 50 µM for 1 hour
limitations
RyR-sensitive flux is not proof of direct binding to a particular RyR isoform. Cell-line exposure responses do not establish dietary prevention of prostate cancer.
nutrient_topic
Boron research collection; topical membership is not evidence of a direct dietary effect. · Boron
organism
Human DU-145, LNCaP and PWR1E cells
plain_language
Different prostate cell types needed different concentrations for the measured response.
primary_references
[boron-p19554099] Receptor activated Ca(2+) release is inhibited by boric acid in prostate cancer cells. (2009). https://pubmed.ncbi.nlm.nih.gov/19554099/ DOI: 10.1371/journal.pone.0006009
tissue_or_cell_type
Cancer and non-tumor prostate cell cultures
Boron: chemistry, nutrient interactions, low-intake studies and mechanistic uncertainties (2026-09-17) · lines 352–363
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Calcium imaging and flow cytometry in three human prostate cell lines · source_derived_draft · unverified_draft
### boron-cell-type-calcium-threshold Significant inhibition of caffeine-evoked calcium release required 20 µM boric acid in LNCaP cells and 150 µM in non-tumor PWR1E cells. Condition category: normal nutrient_topic: Boron research collection; topical membership is not evidence of a direct dietary effect. plain_language: Different prostate cell types needed different concentrations for the measured response. organism: Human DU-145, LNCaP and PWR1E cells tissue_or_cell_type: Cancer and non-tumor prostate cell cultures experimental_model: Calcium imaging and flow cytometry in three human prostate cell lines limitations: RyR-sensitive flux is not proof of direct binding to a particular RyR isoform. Cell-line exposure responses do not establish dietary prevention of prostate cancer. exposure: Boric acid 1–150 µM depending on agonist and cell line; DU-145 storage assay 50 µM for 1 hour evidence_span: {"source_cache": "artifacts/boron-research/19554099.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "17bd65bde36f54d1bb0688118212419b31643b9fc61323d12ef1ad6a78a173bb", "start_char": 0, "end_char": 1809, "text_sha256": "17bd65bde36f54d1bb0688118212419b31643b9fc61323d12ef1ad6a78a173bb"} [boron-p19554099] Receptor activated Ca(2+) release is inhibited by boric acid in prostate cancer cells. (2009). https://pubmed.ncbi.nlm.nih.gov/19554099/ DOI: 10.1371/journal.pone.0006009
Complete structured claim and evidence
Caffeine-derived CYP1A2 indices correlated with clozapine clearance in the 14-person study.
CYP1A2 catalytic activity → Plasma clozapine exposure source_derived_draftungraded
Experimental context and source evidence
evidence_span
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experimental_model
Clinical caffeine phenotyping and prior clozapine exposure
exposure
Caffeine test related to single-dose clozapine kinetics
limitations
Correlation supports enzyme relevance; no DIM administration or prediction of an individual clinical effect.
nutrient_topic
Diindolylmethane (DIM) research collection; topical membership is not evidence of a direct dietary effect. · 3,3'-Diindolylmethane / DIM
organism
14 healthy adults
plain_language
Enzyme activity was linked to drug handling in people, separately from any DIM exposure.
primary_references
[dim-p7893591] Clozapine disposition covaries with CYP1A2 activity determined by a caffeine test. (1994). https://pubmed.ncbi.nlm.nih.gov/7893591/ DOI: 10.1111/j.1365-2125.1994.tb04385.x
tissue_or_cell_type
CYP1A2 phenotype and clozapine disposition
Diindolylmethane (DIM): formation, receptor signaling, metabolism and drug interactions (2026-09-17) · lines 688–699
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Clinical caffeine phenotyping and prior clozapine exposure · source_derived_draft · unverified_draft
### dim-clozapine-phenotype Caffeine-derived CYP1A2 indices correlated with clozapine clearance in the 14-person study. Condition category: normal nutrient_topic: Diindolylmethane (DIM) research collection; topical membership is not evidence of a direct dietary effect. plain_language: Enzyme activity was linked to drug handling in people, separately from any DIM exposure. organism: 14 healthy adults tissue_or_cell_type: CYP1A2 phenotype and clozapine disposition experimental_model: Clinical caffeine phenotyping and prior clozapine exposure limitations: Correlation supports enzyme relevance; no DIM administration or prediction of an individual clinical effect. exposure: Caffeine test related to single-dose clozapine kinetics evidence_span: {"source_cache": "artifacts/dim-research/7893591.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "d568c4f2cdf1fc2d58f2ea22e395a7d7813cef2b1433fe25da51a2c40df5c545", "start_char": 0, "end_char": 849, "text_sha256": "d568c4f2cdf1fc2d58f2ea22e395a7d7813cef2b1433fe25da51a2c40df5c545"} [dim-p7893591] Clozapine disposition covaries with CYP1A2 activity determined by a caffeine test. (1994). https://pubmed.ncbi.nlm.nih.gov/7893591/ DOI: 10.1111/j.1365-2125.1994.tb04385.x
Complete structured claim and evidence
The paraxanthine-to-caffeine ratio was used to phenotype CYP1A2 during smoking cessation.
Human cytochrome P450 1A2 → Caffeine source_derived_draftungraded
Experimental context and source evidence
evidence_span
{"source_cache": "artifacts/dim-research/15289794.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "90eb96e72afdbbb53c322c2be9a34e5aa523c27f2fd0995a8eb224e2ec6e35e2", "start_char": 0, "end_char": 1753, "text_sha256": "90eb96e72afdbbb53c322c2be9a34e5aa523c27f2fd0995a8eb224e2ec6e35e2"}
experimental_model
Repeated caffeine phenotyping after smoking cessation
exposure
Abrupt cessation after run-in; repeated 148-mg caffeine probe doses
limitations
Smoking-cessation kinetics cannot be assigned to starting or stopping DIM. Clinical dose management requires drug-specific monitoring.
nutrient_topic
Diindolylmethane (DIM) research collection; topical membership is not evidence of a direct dietary effect. · 3,3'-Diindolylmethane / DIM
organism
12 heavy smokers
plain_language
Caffeine provides a measurable probe of enzyme activity.
primary_references
[dim-p15289794] Time response of cytochrome P450 1A2 activity on cessation of heavy smoking. (2004). https://pubmed.ncbi.nlm.nih.gov/15289794/ DOI: 10.1016/j.clpt.2004.04.003
tissue_or_cell_type
CYP1A2 activity and caffeine clearance
Diindolylmethane (DIM): formation, receptor signaling, metabolism and drug interactions (2026-09-17) · lines 831–842
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Repeated caffeine phenotyping after smoking cessation · source_derived_draft · unverified_draft
### dim-caffeine-1a2 The paraxanthine-to-caffeine ratio was used to phenotype CYP1A2 during smoking cessation. Condition category: normal nutrient_topic: Diindolylmethane (DIM) research collection; topical membership is not evidence of a direct dietary effect. plain_language: Caffeine provides a measurable probe of enzyme activity. organism: 12 heavy smokers tissue_or_cell_type: CYP1A2 activity and caffeine clearance experimental_model: Repeated caffeine phenotyping after smoking cessation limitations: Smoking-cessation kinetics cannot be assigned to starting or stopping DIM. Clinical dose management requires drug-specific monitoring. exposure: Abrupt cessation after run-in; repeated 148-mg caffeine probe doses evidence_span: {"source_cache": "artifacts/dim-research/15289794.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "90eb96e72afdbbb53c322c2be9a34e5aa523c27f2fd0995a8eb224e2ec6e35e2", "start_char": 0, "end_char": 1753, "text_sha256": "90eb96e72afdbbb53c322c2be9a34e5aa523c27f2fd0995a8eb224e2ec6e35e2"} [dim-p15289794] Time response of cytochrome P450 1A2 activity on cessation of heavy smoking. (2004). https://pubmed.ncbi.nlm.nih.gov/15289794/ DOI: 10.1016/j.clpt.2004.04.003
Complete structured claim and evidence
Caffeine clearance fell by 36.1% after cessation; the fitted half-life of CYP1A2 activity decline was 38.6 hours.
Cessation of cigarette smoking → Caffeine clearance source_derived_draftungraded
Experimental context and source evidence
evidence_span
{"source_cache": "artifacts/dim-research/15289794.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "90eb96e72afdbbb53c322c2be9a34e5aa523c27f2fd0995a8eb224e2ec6e35e2", "start_char": 0, "end_char": 1753, "text_sha256": "90eb96e72afdbbb53c322c2be9a34e5aa523c27f2fd0995a8eb224e2ec6e35e2"}
experimental_model
Repeated caffeine phenotyping after smoking cessation
exposure
Abrupt cessation after run-in; repeated 148-mg caffeine probe doses
limitations
Smoking-cessation kinetics cannot be assigned to starting or stopping DIM. Clinical dose management requires drug-specific monitoring.
nutrient_topic
Diindolylmethane (DIM) research collection; topical membership is not evidence of a direct dietary effect. · 3,3'-Diindolylmethane / DIM
organism
12 heavy smokers
plain_language
Stopping an established inducer can raise exposure to its substrates, but these numbers describe smoking.
primary_references
[dim-p15289794] Time response of cytochrome P450 1A2 activity on cessation of heavy smoking. (2004). https://pubmed.ncbi.nlm.nih.gov/15289794/ DOI: 10.1016/j.clpt.2004.04.003
tissue_or_cell_type
CYP1A2 activity and caffeine clearance
Diindolylmethane (DIM): formation, receptor signaling, metabolism and drug interactions (2026-09-17) · lines 844–855
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Repeated caffeine phenotyping after smoking cessation · source_derived_draft · unverified_draft
### dim-smoking-cessation Caffeine clearance fell by 36.1% after cessation; the fitted half-life of CYP1A2 activity decline was 38.6 hours. Condition category: normal nutrient_topic: Diindolylmethane (DIM) research collection; topical membership is not evidence of a direct dietary effect. plain_language: Stopping an established inducer can raise exposure to its substrates, but these numbers describe smoking. organism: 12 heavy smokers tissue_or_cell_type: CYP1A2 activity and caffeine clearance experimental_model: Repeated caffeine phenotyping after smoking cessation limitations: Smoking-cessation kinetics cannot be assigned to starting or stopping DIM. Clinical dose management requires drug-specific monitoring. exposure: Abrupt cessation after run-in; repeated 148-mg caffeine probe doses evidence_span: {"source_cache": "artifacts/dim-research/15289794.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "90eb96e72afdbbb53c322c2be9a34e5aa523c27f2fd0995a8eb224e2ec6e35e2", "start_char": 0, "end_char": 1753, "text_sha256": "90eb96e72afdbbb53c322c2be9a34e5aa523c27f2fd0995a8eb224e2ec6e35e2"} [dim-p15289794] Time response of cytochrome P450 1A2 activity on cessation of heavy smoking. (2004). https://pubmed.ncbi.nlm.nih.gov/15289794/ DOI: 10.1016/j.clpt.2004.04.003
Complete structured claim and evidence
Nicotine patches did not significantly change caffeine pharmacokinetics or metabolite formation in the crossover study.
Nicotine → Caffeine clearance source_derived_draftungraded
Experimental context and source evidence
evidence_span
{"source_cache": "artifacts/dim-research/21599724.publisher-preview.txt", "locator": "Primary public publisher preview, reference superscripts removed; zero-based, end-exclusive Unicode character offsets", "file_sha256": "2a31ba5c71ba785b8fc6cdec21ed2dfa37686cb6d44dbf22616b0ab9b585a940", "start_char": 0, "end_char": 537, "text_sha256": "2a31ba5c71ba785b8fc6cdec21ed2dfa37686cb6d44dbf22616b0ab9b585a940"}
experimental_model
Randomized crossover nicotine-patch study; full-text extract
exposure
42 mg/day transdermal nicotine or placebo; caffeine probe on day eight
limitations
Nicotine-only exposure differs from smoke exposure; this short study does not test every tissue or nicotine product.
nutrient_topic
Diindolylmethane (DIM) research collection; topical membership is not evidence of a direct dietary effect. · 3,3'-Diindolylmethane / DIM
organism
12 healthy smokers abstinent from tobacco during study
plain_language
Smoking and nicotine alone are not interchangeable CYP1A2 exposures.
primary_references
[dim-p21599724] Effect of nicotine on cytochrome P450 1A2 activity. (2011). https://pubmed.ncbi.nlm.nih.gov/21599724/ DOI: 10.1111/j.1365-2125.2011.04023.x
tissue_or_cell_type
Caffeine-based hepatic CYP1A2 phenotyping
Diindolylmethane (DIM): formation, receptor signaling, metabolism and drug interactions (2026-09-17) · lines 857–868
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Randomized crossover nicotine-patch study; full-text extract · source_derived_draft · unverified_draft
### dim-nicotine-not-smoke Nicotine patches did not significantly change caffeine pharmacokinetics or metabolite formation in the crossover study. Condition category: normal nutrient_topic: Diindolylmethane (DIM) research collection; topical membership is not evidence of a direct dietary effect. plain_language: Smoking and nicotine alone are not interchangeable CYP1A2 exposures. organism: 12 healthy smokers abstinent from tobacco during study tissue_or_cell_type: Caffeine-based hepatic CYP1A2 phenotyping experimental_model: Randomized crossover nicotine-patch study; full-text extract limitations: Nicotine-only exposure differs from smoke exposure; this short study does not test every tissue or nicotine product. exposure: 42 mg/day transdermal nicotine or placebo; caffeine probe on day eight evidence_span: {"source_cache": "artifacts/dim-research/21599724.publisher-preview.txt", "locator": "Primary public publisher preview, reference superscripts removed; zero-based, end-exclusive Unicode character offsets", "file_sha256": "2a31ba5c71ba785b8fc6cdec21ed2dfa37686cb6d44dbf22616b0ab9b585a940", "start_char": 0, "end_char": 537, "text_sha256": "2a31ba5c71ba785b8fc6cdec21ed2dfa37686cb6d44dbf22616b0ab9b585a940"} [dim-p21599724] Effect of nicotine on cytochrome P450 1A2 activity. (2011). https://pubmed.ncbi.nlm.nih.gov/21599724/ DOI: 10.1111/j.1365-2125.2011.04023.x
Complete structured claim and evidence
I3C increased caffeine-probed CYP1A2 activity in 94% of participants in the phase I study.
Indole-3-carbinol / I3C → Human cytochrome P450 1A2 source_derived_draftungraded
Experimental context and source evidence
evidence_span
{"source_cache": "artifacts/dim-research/16103443.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "ece0ac1a0c31053cdc1ec3eefbf9c78887018e0eddf2db36c3a1a07c998e15c4", "start_char": 0, "end_char": 1706, "text_sha256": "ece0ac1a0c31053cdc1ec3eefbf9c78887018e0eddf2db36c3a1a07c998e15c4"}
experimental_model
Phase I placebo run-in and dose escalation
exposure
I3C 400 mg/day then 800 mg/day for four weeks each
limitations
The administered compound was I3C, not DIM. Multiple acid-condensation products and nonrandomized sequential periods prevent assigning the observed fold change specifically to DIM.
nutrient_topic
Diindolylmethane (DIM) research collection; topical membership is not evidence of a direct dietary effect. · 3,3'-Diindolylmethane / DIM
organism
17 women at elevated breast-cancer risk
plain_language
There is human evidence for the precursor, but it must not be silently relabeled as a DIM trial.
primary_references
[dim-p16103443] A phase I study of indole-3-carbinol in women: tolerability and effects. (2005). https://pubmed.ncbi.nlm.nih.gov/16103443/ DOI: 10.1158/1055-9965.epi-05-0121
tissue_or_cell_type
Caffeine CYP1A2 phenotype and estrogen metabolites
Diindolylmethane (DIM): formation, receptor signaling, metabolism and drug interactions (2026-09-17) · lines 1026–1037
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Phase I placebo run-in and dose escalation · source_derived_draft · unverified_draft
### dim-i3c-human-1a2 I3C increased caffeine-probed CYP1A2 activity in 94% of participants in the phase I study. Condition category: normal nutrient_topic: Diindolylmethane (DIM) research collection; topical membership is not evidence of a direct dietary effect. plain_language: There is human evidence for the precursor, but it must not be silently relabeled as a DIM trial. organism: 17 women at elevated breast-cancer risk tissue_or_cell_type: Caffeine CYP1A2 phenotype and estrogen metabolites experimental_model: Phase I placebo run-in and dose escalation limitations: The administered compound was I3C, not DIM. Multiple acid-condensation products and nonrandomized sequential periods prevent assigning the observed fold change specifically to DIM. exposure: I3C 400 mg/day then 800 mg/day for four weeks each evidence_span: {"source_cache": "artifacts/dim-research/16103443.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "ece0ac1a0c31053cdc1ec3eefbf9c78887018e0eddf2db36c3a1a07c998e15c4", "start_char": 0, "end_char": 1706, "text_sha256": "ece0ac1a0c31053cdc1ec3eefbf9c78887018e0eddf2db36c3a1a07c998e15c4"} [dim-p16103443] A phase I study of indole-3-carbinol in women: tolerability and effects. (2005). https://pubmed.ncbi.nlm.nih.gov/16103443/ DOI: 10.1158/1055-9965.epi-05-0121
Complete structured claim and evidence
No statistically significant change in caffeine probe pharmacokinetics was found after berberine.
Berberine → CYP1A2 activity measured by probe-drug phenotyping source_derived_draftungraded
Experimental context and source evidence
evidence_span
{"source_cache": "artifacts/berberine-research/21870106.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "12e465c3c0a8ce995697a6fb9bf77c079e38b413e82c8b4f2a82e45a3dbf8ae5", "start_char": 0, "end_char": 1817, "text_sha256": "12e465c3c0a8ce995697a6fb9bf77c079e38b413e82c8b4f2a82e45a3dbf8ae5"}
experimental_model
Two-phase randomized crossover enzyme-phenotyping study
exposure
Berberine 300 mg three times daily for 14 days versus placebo
limitations
Small short-term study. Probe metabolic ratios are not percentage inhibition of every substrate. No universal dose-adjustment rule; no statistically significant effect is not equivalence.
nutrient_topic
Berberine research collection; topical membership is not evidence of a direct dietary effect. · Berberine
organism
Healthy human male volunteers; 17 completed
plain_language
This study did not show a CYP1A2 effect matching the effects on three other enzymes.
primary_references
[berberine-p21870106] Repeated administration of berberine inhibits cytochromes P450 in humans. (2012). https://pubmed.ncbi.nlm.nih.gov/21870106/ DOI: 10.1007/s00228-011-1108-2
tissue_or_cell_type
Oral probe pharmacokinetics and urinary metabolite ratios
Berberine: metabolism, nutrient connections and drug interactions (2026-09-17) · lines 675–686
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Two-phase randomized crossover enzyme-phenotyping study · source_derived_draft · unverified_draft
### berberine-human-cyp-1a2-null No statistically significant change in caffeine probe pharmacokinetics was found after berberine. Condition category: normal nutrient_topic: Berberine research collection; topical membership is not evidence of a direct dietary effect. plain_language: This study did not show a CYP1A2 effect matching the effects on three other enzymes. organism: Healthy human male volunteers; 17 completed tissue_or_cell_type: Oral probe pharmacokinetics and urinary metabolite ratios experimental_model: Two-phase randomized crossover enzyme-phenotyping study limitations: Small short-term study. Probe metabolic ratios are not percentage inhibition of every substrate. No universal dose-adjustment rule; no statistically significant effect is not equivalence. exposure: Berberine 300 mg three times daily for 14 days versus placebo evidence_span: {"source_cache": "artifacts/berberine-research/21870106.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "12e465c3c0a8ce995697a6fb9bf77c079e38b413e82c8b4f2a82e45a3dbf8ae5", "start_char": 0, "end_char": 1817, "text_sha256": "12e465c3c0a8ce995697a6fb9bf77c079e38b413e82c8b4f2a82e45a3dbf8ae5"} [berberine-p21870106] Repeated administration of berberine inhibits cytochromes P450 in humans. (2012). https://pubmed.ncbi.nlm.nih.gov/21870106/ DOI: 10.1007/s00228-011-1108-2
Complete structured claim and evidence
The theanine-caffeine combination improved simple reaction time in the acute crossover experiment.
L-Theanine plus caffeine, study-specific combination → Simple reaction time source_derived_draftungraded
Experimental context and source evidence
evidence_span
{"source_cache": "artifacts/theanine-research/18006208.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "387d341f5aec1fb42bed06021ceb14cc8b49bfdf0f5502284a98806ca732cbdf", "start_char": 0, "end_char": 1386, "text_sha256": "387d341f5aec1fb42bed06021ceb14cc8b49bfdf0f5502284a98806ca732cbdf"}
experimental_model
Randomized double-blind balanced crossover experiment
exposure
250 mg theanine, 150 mg caffeine, combination and placebo
limitations
Acute effects depend on task and treatment. Benefits of the mixture do not establish synergy for all outcomes or neutralization of caffeine.
nutrient_topic
L-Theanine research collection; topical membership is not evidence of a direct dietary effect. · L-Theanine
organism
Healthy adults
plain_language
A specific test result is more precise than a claim of globally improved intelligence.
primary_references
[theanine-p18006208] The effects of L-theanine, caffeine and their combination on cognition and mood. (2008). https://pubmed.ncbi.nlm.nih.gov/18006208/ DOI: 10.1016/j.biopsycho.2007.09.008
tissue_or_cell_type
Cognition and subjective state
L-Theanine: metabolism, neural signaling, nutrient connections and human outcomes (2026-09-17) · lines 939–950
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Randomized double-blind balanced crossover experiment · source_derived_draft · unverified_draft
### theanine-caffeine-simple-reaction The theanine-caffeine combination improved simple reaction time in the acute crossover experiment. Condition category: normal nutrient_topic: L-Theanine research collection; topical membership is not evidence of a direct dietary effect. plain_language: A specific test result is more precise than a claim of globally improved intelligence. organism: Healthy adults tissue_or_cell_type: Cognition and subjective state experimental_model: Randomized double-blind balanced crossover experiment limitations: Acute effects depend on task and treatment. Benefits of the mixture do not establish synergy for all outcomes or neutralization of caffeine. exposure: 250 mg theanine, 150 mg caffeine, combination and placebo evidence_span: {"source_cache": "artifacts/theanine-research/18006208.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "387d341f5aec1fb42bed06021ceb14cc8b49bfdf0f5502284a98806ca732cbdf", "start_char": 0, "end_char": 1386, "text_sha256": "387d341f5aec1fb42bed06021ceb14cc8b49bfdf0f5502284a98806ca732cbdf"} [theanine-p18006208] The effects of L-theanine, caffeine and their combination on cognition and mood. (2008). https://pubmed.ncbi.nlm.nih.gov/18006208/ DOI: 10.1016/j.biopsycho.2007.09.008
Complete structured claim and evidence
Theanine improved visual recognition reaction time in this small acute study; caffeine and the combination also improved it.
L-Theanine → Visual recognition reaction time source_derived_draftungraded
Experimental context and source evidence
evidence_span
{"source_cache": "artifacts/theanine-research/26869148.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "9e57a4cbb05f109037735324857cc3fc4ac55dd8cb76f50979e820a1da52bd60", "start_char": 0, "end_char": 1813, "text_sha256": "9e57a4cbb05f109037735324857cc3fc4ac55dd8cb76f50979e820a1da52bd60"}
experimental_model
Five-way crossover visual discrimination experiment
exposure
200 mg theanine, 160 mg caffeine, combination, tea and placebo
limitations
Small acute study. Larger combination effects were interpreted as additive; statistical interaction was not significant.
nutrient_topic
L-Theanine research collection; topical membership is not evidence of a direct dietary effect. · L-Theanine
organism
20 healthy men
plain_language
Results are tied to a particular task and population.
primary_references
[theanine-p26869148] Acute effects of theanine, caffeine and theanine-caffeine combination on attention. (2017). https://pubmed.ncbi.nlm.nih.gov/26869148/ DOI: 10.1080/1028415x.2016.1144845
tissue_or_cell_type
Reaction time and event-related potentials
L-Theanine: metabolism, neural signaling, nutrient connections and human outcomes (2026-09-17) · lines 991–1002
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Five-way crossover visual discrimination experiment · source_derived_draft · unverified_draft
### theanine-visual-recognition Theanine improved visual recognition reaction time in this small acute study; caffeine and the combination also improved it. Condition category: normal nutrient_topic: L-Theanine research collection; topical membership is not evidence of a direct dietary effect. plain_language: Results are tied to a particular task and population. organism: 20 healthy men tissue_or_cell_type: Reaction time and event-related potentials experimental_model: Five-way crossover visual discrimination experiment limitations: Small acute study. Larger combination effects were interpreted as additive; statistical interaction was not significant. exposure: 200 mg theanine, 160 mg caffeine, combination, tea and placebo evidence_span: {"source_cache": "artifacts/theanine-research/26869148.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "9e57a4cbb05f109037735324857cc3fc4ac55dd8cb76f50979e820a1da52bd60", "start_char": 0, "end_char": 1813, "text_sha256": "9e57a4cbb05f109037735324857cc3fc4ac55dd8cb76f50979e820a1da52bd60"} [theanine-p26869148] Acute effects of theanine, caffeine and theanine-caffeine combination on attention. (2017). https://pubmed.ncbi.nlm.nih.gov/26869148/ DOI: 10.1080/1028415x.2016.1144845
Complete structured claim and evidence
Theanine attenuated the caffeine-associated blood-pressure response in the experiment.
L-Theanine → Arterial blood pressure source_derived_draftungraded
Experimental context and source evidence
evidence_span
{"source_cache": "artifacts/theanine-research/17891480.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "dcd12cbd6fb30feee591192380733184f9928be3c146e39a4debc121a05b8815", "start_char": 0, "end_char": 1581, "text_sha256": "dcd12cbd6fb30feee591192380733184f9928be3c146e39a4debc121a05b8815"}
experimental_model
Randomized double-blind caffeine interaction experiment
exposure
250 mg caffeine with or without 200 mg theanine
limitations
Acute caffeine exposure; no basis for treating chronic hypertension or assuming caffeine adverse effects are all prevented.
nutrient_topic
L-Theanine research collection; topical membership is not evidence of a direct dietary effect. · L-Theanine
organism
48 healthy humans
plain_language
One caffeine response was reduced; that does not make caffeine physiologically inactive.
primary_references
[theanine-p17891480] Time for tea: mood, blood pressure and cognitive performance effects of caffeine and theanine administered alone and together. (2008). https://pubmed.ncbi.nlm.nih.gov/17891480/ DOI: 10.1007/s00213-007-0938-1
tissue_or_cell_type
Blood pressure, mood and visual attention
L-Theanine: metabolism, neural signaling, nutrient connections and human outcomes (2026-09-17) · lines 1004–1015
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Randomized double-blind caffeine interaction experiment · source_derived_draft · unverified_draft
### theanine-caffeine-pressure Theanine attenuated the caffeine-associated blood-pressure response in the experiment. Condition category: normal nutrient_topic: L-Theanine research collection; topical membership is not evidence of a direct dietary effect. plain_language: One caffeine response was reduced; that does not make caffeine physiologically inactive. organism: 48 healthy humans tissue_or_cell_type: Blood pressure, mood and visual attention experimental_model: Randomized double-blind caffeine interaction experiment limitations: Acute caffeine exposure; no basis for treating chronic hypertension or assuming caffeine adverse effects are all prevented. exposure: 250 mg caffeine with or without 200 mg theanine evidence_span: {"source_cache": "artifacts/theanine-research/17891480.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "dcd12cbd6fb30feee591192380733184f9928be3c146e39a4debc121a05b8815", "start_char": 0, "end_char": 1581, "text_sha256": "dcd12cbd6fb30feee591192380733184f9928be3c146e39a4debc121a05b8815"} [theanine-p17891480] Time for tea: mood, blood pressure and cognitive performance effects of caffeine and theanine administered alone and together. (2008). https://pubmed.ncbi.nlm.nih.gov/17891480/ DOI: 10.1007/s00213-007-0938-1
Complete structured claim and evidence
Theanine did not significantly reduce caffeine-associated jitteriness in the same experiment.
L-Theanine → Subjective jitteriness source_derived_draftungraded
Experimental context and source evidence
evidence_span
{"source_cache": "artifacts/theanine-research/17891480.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "dcd12cbd6fb30feee591192380733184f9928be3c146e39a4debc121a05b8815", "start_char": 0, "end_char": 1581, "text_sha256": "dcd12cbd6fb30feee591192380733184f9928be3c146e39a4debc121a05b8815"}
experimental_model
Randomized double-blind caffeine interaction experiment
exposure
250 mg caffeine with or without 200 mg theanine
limitations
Acute caffeine exposure; no basis for treating chronic hypertension or assuming caffeine adverse effects are all prevented.
nutrient_topic
L-Theanine research collection; topical membership is not evidence of a direct dietary effect. · L-Theanine
organism
48 healthy humans
plain_language
The blood-pressure result cannot be generalized to every subjective effect.
primary_references
[theanine-p17891480] Time for tea: mood, blood pressure and cognitive performance effects of caffeine and theanine administered alone and together. (2008). https://pubmed.ncbi.nlm.nih.gov/17891480/ DOI: 10.1007/s00213-007-0938-1
tissue_or_cell_type
Blood pressure, mood and visual attention
L-Theanine: metabolism, neural signaling, nutrient connections and human outcomes (2026-09-17) · lines 1017–1028
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Randomized double-blind caffeine interaction experiment · source_derived_draft · unverified_draft
### theanine-caffeine-jitteriness-null Theanine did not significantly reduce caffeine-associated jitteriness in the same experiment. Condition category: normal nutrient_topic: L-Theanine research collection; topical membership is not evidence of a direct dietary effect. plain_language: The blood-pressure result cannot be generalized to every subjective effect. organism: 48 healthy humans tissue_or_cell_type: Blood pressure, mood and visual attention experimental_model: Randomized double-blind caffeine interaction experiment limitations: Acute caffeine exposure; no basis for treating chronic hypertension or assuming caffeine adverse effects are all prevented. exposure: 250 mg caffeine with or without 200 mg theanine evidence_span: {"source_cache": "artifacts/theanine-research/17891480.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "dcd12cbd6fb30feee591192380733184f9928be3c146e39a4debc121a05b8815", "start_char": 0, "end_char": 1581, "text_sha256": "dcd12cbd6fb30feee591192380733184f9928be3c146e39a4debc121a05b8815"} [theanine-p17891480] Time for tea: mood, blood pressure and cognitive performance effects of caffeine and theanine administered alone and together. (2008). https://pubmed.ncbi.nlm.nih.gov/17891480/ DOI: 10.1007/s00213-007-0938-1
Complete structured claim and evidence
Concurrent caffeine raised melatonin peak concentration by 142% and AUC by 120% on average.
Caffeine → Circulating melatonin exposure, route and timing specified source_derived_draftungraded
Experimental context and source evidence
evidence_span
{"source_cache": "artifacts/melatonin-research/14616429.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "6a8b06b9e1bcb570dca49735b73c2c7360a77381ae6fa25744bcccee7ceb52d8", "start_char": 0, "end_char": 1070, "text_sha256": "6a8b06b9e1bcb570dca49735b73c2c7360a77381ae6fa25744bcccee7ceb52d8"}
experimental_model
Concurrent caffeine interaction study
exposure
6 mg melatonin alone or with three 200 mg caffeine doses
limitations
Caffeine schedule and amount were study-specific. CYP1A2 inhibition was the proposed mechanism; higher melatonin exposure does not imply better sleep while using caffeine.
nutrient_topic
Melatonin research collection; topical membership is not evidence of a direct dietary effect. · Melatonin
organism
Twelve humans, six smokers and six nonsmokers
plain_language
One substance can promote wakefulness while increasing blood exposure to another substance.
primary_references
[melatonin-p14616429] Effects of caffeine intake on the pharmacokinetics of melatonin, a probe drug for CYP1A2 activity. (2003). https://pubmed.ncbi.nlm.nih.gov/14616429/ DOI: 10.1046/j.1365-2125.2003.01933.x
tissue_or_cell_type
Oral melatonin pharmacokinetics
Melatonin: synthesis, receptors, circadian timing and nutrient interactions (2026-09-17) · lines 708–719
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Concurrent caffeine interaction study · source_derived_draft · unverified_draft
### melatonin-caffeine-exposure Concurrent caffeine raised melatonin peak concentration by 142% and AUC by 120% on average. Condition category: normal nutrient_topic: Melatonin research collection; topical membership is not evidence of a direct dietary effect. plain_language: One substance can promote wakefulness while increasing blood exposure to another substance. organism: Twelve humans, six smokers and six nonsmokers tissue_or_cell_type: Oral melatonin pharmacokinetics experimental_model: Concurrent caffeine interaction study limitations: Caffeine schedule and amount were study-specific. CYP1A2 inhibition was the proposed mechanism; higher melatonin exposure does not imply better sleep while using caffeine. exposure: 6 mg melatonin alone or with three 200 mg caffeine doses evidence_span: {"source_cache": "artifacts/melatonin-research/14616429.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "6a8b06b9e1bcb570dca49735b73c2c7360a77381ae6fa25744bcccee7ceb52d8", "start_char": 0, "end_char": 1070, "text_sha256": "6a8b06b9e1bcb570dca49735b73c2c7360a77381ae6fa25744bcccee7ceb52d8"} [melatonin-p14616429] Effects of caffeine intake on the pharmacokinetics of melatonin, a probe drug for CYP1A2 activity. (2003). https://pubmed.ncbi.nlm.nih.gov/14616429/ DOI: 10.1046/j.1365-2125.2003.01933.x
Complete structured claim and evidence
Crystallography and extracted-flavin analysis identified FAD bound to recombinant human POR.
NADPH-cytochrome P450 oxidoreductase / POR → FAD source_derived_draftungraded
Experimental context and source evidence
cross_nutrient
true
evidence_location
Primary Results, wild-type structure and cofactor-binding sites; Methods flavin extraction/HPLC.
experimental_model
Human POR structure and flavin-content analysis
exposure
Recombinant N-terminally truncated human POR; X-ray structure and HPLC flavin assays.
limitations
The structural study did not measure vitamin D outcomes after riboflavin dosing; linkage to CYP2R1 comes from the separate direct reconstitution record.
nutrient
Vitamin D2 and D3 · Vitamin D2 and D3
nutrient_topic
Vitamin D2 and D3 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin D2 and D3
organism
Homo sapiens protein
plain_language
POR carries a FAD cofactor derived from vitamin B2.
primary_references
[xia2011] Structural basis for human NADPH-cytochrome P450 oxidoreductase deficiency. (2011). https://pubmed.ncbi.nlm.nih.gov/21808038/ DOI: 10.1073/pnas.1106632108
tissue_or_cell_type
POR cofactor-binding domain
Vitamin D2 and D3: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 407–420
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human POR structure and flavin-content analysis · source_derived_draft · unverified_draft
### vd-act-por-fad Crystallography and extracted-flavin analysis identified FAD bound to recombinant human POR. Condition category: normal nutrient_topic: Vitamin D2 and D3 research collection; topical membership is not evidence of a direct dietary effect. plain_language: POR carries a FAD cofactor derived from vitamin B2. organism: Homo sapiens protein tissue_or_cell_type: POR cofactor-binding domain experimental_model: Human POR structure and flavin-content analysis limitations: The structural study did not measure vitamin D outcomes after riboflavin dosing; linkage to CYP2R1 comes from the separate direct reconstitution record. exposure: Recombinant N-terminally truncated human POR; X-ray structure and HPLC flavin assays. cross_nutrient: true evidence_location: Primary Results, wild-type structure and cofactor-binding sites; Methods flavin extraction/HPLC. nutrient: Vitamin D2 and D3 [xia2011] Structural basis for human NADPH-cytochrome P450 oxidoreductase deficiency. (2011). https://pubmed.ncbi.nlm.nih.gov/21808038/ DOI: 10.1073/pnas.1106632108
Complete structured claim and evidence
Crystallography and extracted-flavin analysis identified FMN bound to recombinant human POR.
NADPH-cytochrome P450 oxidoreductase / POR → Flavin mononucleotide source_derived_draftungraded
Experimental context and source evidence
cross_nutrient
true
evidence_location
Primary Results, wild-type structure and cofactor-binding sites; Methods flavin extraction/HPLC.
experimental_model
Human POR structure and flavin-content analysis
exposure
Recombinant N-terminally truncated human POR; X-ray structure and HPLC flavin assays.
limitations
The structural study did not measure vitamin D outcomes after riboflavin dosing; linkage to CYP2R1 comes from the separate direct reconstitution record.
nutrient
Vitamin D2 and D3 · Vitamin D2 and D3
nutrient_topic
Vitamin D2 and D3 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin D2 and D3
organism
Homo sapiens protein
plain_language
POR carries a FMN cofactor derived from vitamin B2.
primary_references
[xia2011] Structural basis for human NADPH-cytochrome P450 oxidoreductase deficiency. (2011). https://pubmed.ncbi.nlm.nih.gov/21808038/ DOI: 10.1073/pnas.1106632108
tissue_or_cell_type
POR cofactor-binding domain
Vitamin D2 and D3: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 422–435
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human POR structure and flavin-content analysis · source_derived_draft · unverified_draft
### vd-act-por-fmn Crystallography and extracted-flavin analysis identified FMN bound to recombinant human POR. Condition category: normal nutrient_topic: Vitamin D2 and D3 research collection; topical membership is not evidence of a direct dietary effect. plain_language: POR carries a FMN cofactor derived from vitamin B2. organism: Homo sapiens protein tissue_or_cell_type: POR cofactor-binding domain experimental_model: Human POR structure and flavin-content analysis limitations: The structural study did not measure vitamin D outcomes after riboflavin dosing; linkage to CYP2R1 comes from the separate direct reconstitution record. exposure: Recombinant N-terminally truncated human POR; X-ray structure and HPLC flavin assays. cross_nutrient: true evidence_location: Primary Results, wild-type structure and cofactor-binding sites; Methods flavin extraction/HPLC. nutrient: Vitamin D2 and D3 [xia2011] Structural basis for human NADPH-cytochrome P450 oxidoreductase deficiency. (2011). https://pubmed.ncbi.nlm.nih.gov/21808038/ DOI: 10.1073/pnas.1106632108
Complete structured claim and evidence
POR Y181D lacked bound FMN and poorly supported CYP1A2-catalyzed reactions despite retaining FAD binding and NADPH utilization.
Human POR Y181D variant → Human cytochrome P450 1A2 source_derived_draftungraded
Experimental context and source evidence
availability_state
machinery_impairment Imported condition classification; unverified.
evidence_span
{"source_cache": "artifacts/dim-research/19884324.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "3f702cc9af1528241d8572b8bcafc23dacb5ed3cacf6bb77403e8aa40d21a214", "start_char": 0, "end_char": 1738, "text_sha256": "3f702cc9af1528241d8572b8bcafc23dacb5ed3cacf6bb77403e8aa40d21a214"}
experimental_model
Recombinant protein and engineered bacterial coexpression
exposure
POR mutation and added FMN
limitations
In-vitro rescue of one mutant; not a dietary-riboflavin deficiency experiment or evidence that FMN reverses a DIM-drug interaction.
nutrient_topic
Diindolylmethane (DIM) research collection; topical membership is not evidence of a direct dietary effect. · 3,3'-Diindolylmethane / DIM
organism
Human POR Y181D and human CYP1A2 in engineered systems
plain_language
Inducing an enzyme is not enough if its electron-supply machinery fails.
primary_references
[dim-p19884324] Human cytochrome P450 oxidoreductase deficiency caused by the Y181D mutation: molecular consequences and rescue of defect. (2010). https://pubmed.ncbi.nlm.nih.gov/19884324/ DOI: 10.1124/dmd.109.030445
tissue_or_cell_type
FMN-dependent electron transfer
trigger_kind
machinery_impairment Imported condition classification; unverified.
Diindolylmethane (DIM): formation, receptor signaling, metabolism and drug interactions (2026-09-17) · lines 272–283
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Recombinant protein and engineered bacterial coexpression · source_derived_draft · unverified_draft
### dim-por-fmn-loss POR Y181D lacked bound FMN and poorly supported CYP1A2-catalyzed reactions despite retaining FAD binding and NADPH utilization. Condition category: machinery_impairment nutrient_topic: Diindolylmethane (DIM) research collection; topical membership is not evidence of a direct dietary effect. plain_language: Inducing an enzyme is not enough if its electron-supply machinery fails. organism: Human POR Y181D and human CYP1A2 in engineered systems tissue_or_cell_type: FMN-dependent electron transfer experimental_model: Recombinant protein and engineered bacterial coexpression limitations: In-vitro rescue of one mutant; not a dietary-riboflavin deficiency experiment or evidence that FMN reverses a DIM-drug interaction. exposure: POR mutation and added FMN evidence_span: {"source_cache": "artifacts/dim-research/19884324.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "3f702cc9af1528241d8572b8bcafc23dacb5ed3cacf6bb77403e8aa40d21a214", "start_char": 0, "end_char": 1738, "text_sha256": "3f702cc9af1528241d8572b8bcafc23dacb5ed3cacf6bb77403e8aa40d21a214"} [dim-p19884324] Human cytochrome P450 oxidoreductase deficiency caused by the Y181D mutation: molecular consequences and rescue of defect. (2010). https://pubmed.ncbi.nlm.nih.gov/19884324/ DOI: 10.1124/dmd.109.030445
Complete structured claim and evidence
Added FMN restored CYP1A2 ethoxyresorufin activity in POR Y181D membranes to 37% of the wild-type system.
Flavin mononucleotide → CYP1A2 catalytic activity source_derived_draftungraded
Experimental context and source evidence
availability_state
machinery_impairment Imported condition classification; unverified.
evidence_span
{"source_cache": "artifacts/dim-research/19884324.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "3f702cc9af1528241d8572b8bcafc23dacb5ed3cacf6bb77403e8aa40d21a214", "start_char": 0, "end_char": 1738, "text_sha256": "3f702cc9af1528241d8572b8bcafc23dacb5ed3cacf6bb77403e8aa40d21a214"}
experimental_model
Recombinant protein and engineered bacterial coexpression
exposure
POR mutation and added FMN
limitations
In-vitro rescue of one mutant; not a dietary-riboflavin deficiency experiment or evidence that FMN reverses a DIM-drug interaction.
nutrient_topic
Diindolylmethane (DIM) research collection; topical membership is not evidence of a direct dietary effect. · 3,3'-Diindolylmethane / DIM
organism
Human POR Y181D and human CYP1A2 in engineered systems
plain_language
A specific cofactor-binding defect could be partly rescued in the assay.
primary_references
[dim-p19884324] Human cytochrome P450 oxidoreductase deficiency caused by the Y181D mutation: molecular consequences and rescue of defect. (2010). https://pubmed.ncbi.nlm.nih.gov/19884324/ DOI: 10.1124/dmd.109.030445
tissue_or_cell_type
FMN-dependent electron transfer
trigger_kind
machinery_impairment Imported condition classification; unverified.
Diindolylmethane (DIM): formation, receptor signaling, metabolism and drug interactions (2026-09-17) · lines 285–296
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Recombinant protein and engineered bacterial coexpression · source_derived_draft · unverified_draft
### dim-por-fmn-rescue Added FMN restored CYP1A2 ethoxyresorufin activity in POR Y181D membranes to 37% of the wild-type system. Condition category: machinery_impairment nutrient_topic: Diindolylmethane (DIM) research collection; topical membership is not evidence of a direct dietary effect. plain_language: A specific cofactor-binding defect could be partly rescued in the assay. organism: Human POR Y181D and human CYP1A2 in engineered systems tissue_or_cell_type: FMN-dependent electron transfer experimental_model: Recombinant protein and engineered bacterial coexpression limitations: In-vitro rescue of one mutant; not a dietary-riboflavin deficiency experiment or evidence that FMN reverses a DIM-drug interaction. exposure: POR mutation and added FMN evidence_span: {"source_cache": "artifacts/dim-research/19884324.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "3f702cc9af1528241d8572b8bcafc23dacb5ed3cacf6bb77403e8aa40d21a214", "start_char": 0, "end_char": 1738, "text_sha256": "3f702cc9af1528241d8572b8bcafc23dacb5ed3cacf6bb77403e8aa40d21a214"} [dim-p19884324] Human cytochrome P450 oxidoreductase deficiency caused by the Y181D mutation: molecular consequences and rescue of defect. (2010). https://pubmed.ncbi.nlm.nih.gov/19884324/ DOI: 10.1124/dmd.109.030445
Complete structured claim and evidence
The CYP1A2 structure places its ligand above the heme prosthetic group.
Human cytochrome P450 1A2 → Heme source_derived_draftungraded
Experimental context and source evidence
evidence_span
{"source_cache": "artifacts/dim-research/17311915.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "4c3f047d0ee4583ca15aae2c7059d2237b02105371fda21bf32639cbaad2d318", "start_char": 0, "end_char": 1400, "text_sha256": "4c3f047d0ee4583ca15aae2c7059d2237b02105371fda21bf32639cbaad2d318"}
experimental_model
X-ray crystallography
exposure
Alpha-naphthoflavone-bound structure at 1.95 angstrom resolution
limitations
Structural enzyme requirement; not proof that DIM depletes iron or that iron supplementation changes DIM response.
nutrient_topic
Diindolylmethane (DIM) research collection; topical membership is not evidence of a direct dietary effect. · 3,3'-Diindolylmethane / DIM
organism
Purified human CYP1A2
plain_language
The induced enzyme still needs its iron-containing catalytic machinery.
primary_references
[dim-p17311915] Adaptations for the oxidation of polycyclic aromatic hydrocarbons exhibited by the structure of human P450 1A2. (2007). https://pubmed.ncbi.nlm.nih.gov/17311915/ DOI: 10.1074/jbc.m611692200
tissue_or_cell_type
Catalytic pocket
Diindolylmethane (DIM): formation, receptor signaling, metabolism and drug interactions (2026-09-17) · lines 259–270
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · X-ray crystallography · source_derived_draft · unverified_draft
### dim-cyp1a2-heme The CYP1A2 structure places its ligand above the heme prosthetic group. Condition category: normal nutrient_topic: Diindolylmethane (DIM) research collection; topical membership is not evidence of a direct dietary effect. plain_language: The induced enzyme still needs its iron-containing catalytic machinery. organism: Purified human CYP1A2 tissue_or_cell_type: Catalytic pocket experimental_model: X-ray crystallography limitations: Structural enzyme requirement; not proof that DIM depletes iron or that iron supplementation changes DIM response. exposure: Alpha-naphthoflavone-bound structure at 1.95 angstrom resolution evidence_span: {"source_cache": "artifacts/dim-research/17311915.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "4c3f047d0ee4583ca15aae2c7059d2237b02105371fda21bf32639cbaad2d318", "start_char": 0, "end_char": 1400, "text_sha256": "4c3f047d0ee4583ca15aae2c7059d2237b02105371fda21bf32639cbaad2d318"} [dim-p17311915] Adaptations for the oxidation of polycyclic aromatic hydrocarbons exhibited by the structure of human P450 1A2. (2007). https://pubmed.ncbi.nlm.nih.gov/17311915/ DOI: 10.1074/jbc.m611692200
Complete structured claim and evidence
The XDH form transfers purine-derived electrons through its iron-sulfur centers and FAD to NAD+, producing NADH.
Human xanthine oxidoreductase / XDH → NAD+ source_derived_draftungraded
Experimental context and source evidence
evidence_span
{"source_cache": "artifacts/molybdenum-research/37713777.fulltext.txt", "locator": "Exact primary full-text span; zero-based, end-exclusive Unicode character offsets", "file_sha256": "a8092b2aa7328b59f0275dd8a37d2a2dbb5abb2a32236d0cab5fffcc1ddc671d", "start_char": 0, "end_char": 1579, "text_sha256": "18325172be489f8f4beae16c04dbc4f49f94c87186321e32aede61f27089c7c4"}
experimental_model
Recombinant human XDH variants with urate, superoxide and NO assays
exposure
Xanthine, oxygen and inorganic nitrite assays
limitations
Canonical electron-transfer mechanism stated in this primary article; not an experiment on dietary B2 or niacin depletion.
nutrient_topic
Molybdenum research collection; topical membership is not evidence of a direct dietary effect. · Molybdenum
organism
Homo sapiens protein
plain_language
Riboflavin-derived FAD, iron-sulfur centers and niacin-derived NAD work alongside molybdenum.
primary_references
[mo-p37713777] Natural mutations of human XDH promote the nitrite (NO2-)-reductase capacity of xanthine oxidoreductase: A novel mechanism to promote redox health? (2023). https://pubmed.ncbi.nlm.nih.gov/37713777/ DOI: 10.1016/j.redox.2023.102864
tissue_or_cell_type
Purified human enzyme
Molybdenum: cofactor assembly, sulfur metabolism and nutrient interactions (2026-09-17) · lines 768–779
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Recombinant human XDH variants with urate, superoxide and NO assays · source_derived_draft · unverified_draft
### mo-xdh-nad The XDH form transfers purine-derived electrons through its iron-sulfur centers and FAD to NAD+, producing NADH. Condition category: normal nutrient_topic: Molybdenum research collection; topical membership is not evidence of a direct dietary effect. plain_language: Riboflavin-derived FAD, iron-sulfur centers and niacin-derived NAD work alongside molybdenum. organism: Homo sapiens protein tissue_or_cell_type: Purified human enzyme experimental_model: Recombinant human XDH variants with urate, superoxide and NO assays limitations: Canonical electron-transfer mechanism stated in this primary article; not an experiment on dietary B2 or niacin depletion. exposure: Xanthine, oxygen and inorganic nitrite assays evidence_span: {"source_cache": "artifacts/molybdenum-research/37713777.fulltext.txt", "locator": "Exact primary full-text span; zero-based, end-exclusive Unicode character offsets", "file_sha256": "a8092b2aa7328b59f0275dd8a37d2a2dbb5abb2a32236d0cab5fffcc1ddc671d", "start_char": 0, "end_char": 1579, "text_sha256": "18325172be489f8f4beae16c04dbc4f49f94c87186321e32aede61f27089c7c4"} [mo-p37713777] Natural mutations of human XDH promote the nitrite (NO2-)-reductase capacity of xanthine oxidoreductase: A novel mechanism to promote redox health? (2023). https://pubmed.ncbi.nlm.nih.gov/37713777/ DOI: 10.1016/j.redox.2023.102864
Complete structured claim and evidence
CYP1A2 was the principal high-affinity, but not exclusive, enzyme for melatonin 6-hydroxylation.
Human cytochrome P450 1A2 → Melatonin source_derived_draftungraded
Experimental context and source evidence
evidence_span
{"source_cache": "artifacts/dim-research/11317475.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "503f4e9d299c6c978aa1e867a32cdc7b4f5c191290b74415f0f152d3b2f0d87d", "start_char": 0, "end_char": 1580, "text_sha256": "503f4e9d299c6c978aa1e867a32cdc7b4f5c191290b74415f0f152d3b2f0d87d"}
experimental_model
Human microsomes, expressed enzymes and inhibition assays
exposure
Substrate range 1-1000 micromolar
limitations
In-vitro pathway identification; no DIM coadministration, sleep outcome or proof that DIM lowers nighttime melatonin.
nutrient_topic
Diindolylmethane (DIM) research collection; topical membership is not evidence of a direct dietary effect. · 3,3'-Diindolylmethane / DIM
organism
Human liver CYP systems
plain_language
Melatonin shares the enzyme; a DIM effect on sleep cannot be read directly from this edge.
primary_references
[dim-p11317475] Cytochrome P450 isoforms involved in melatonin metabolism in human liver microsomes. (2001). https://pubmed.ncbi.nlm.nih.gov/11317475/ DOI: 10.1007/s002280000245
tissue_or_cell_type
Melatonin 6-hydroxylation
Diindolylmethane (DIM): formation, receptor signaling, metabolism and drug interactions (2026-09-17) · lines 818–829
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human microsomes, expressed enzymes and inhibition assays · source_derived_draft · unverified_draft
### dim-melatonin-1a2 CYP1A2 was the principal high-affinity, but not exclusive, enzyme for melatonin 6-hydroxylation. Condition category: normal nutrient_topic: Diindolylmethane (DIM) research collection; topical membership is not evidence of a direct dietary effect. plain_language: Melatonin shares the enzyme; a DIM effect on sleep cannot be read directly from this edge. organism: Human liver CYP systems tissue_or_cell_type: Melatonin 6-hydroxylation experimental_model: Human microsomes, expressed enzymes and inhibition assays limitations: In-vitro pathway identification; no DIM coadministration, sleep outcome or proof that DIM lowers nighttime melatonin. exposure: Substrate range 1-1000 micromolar evidence_span: {"source_cache": "artifacts/dim-research/11317475.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "503f4e9d299c6c978aa1e867a32cdc7b4f5c191290b74415f0f152d3b2f0d87d", "start_char": 0, "end_char": 1580, "text_sha256": "503f4e9d299c6c978aa1e867a32cdc7b4f5c191290b74415f0f152d3b2f0d87d"} [dim-p11317475] Cytochrome P450 isoforms involved in melatonin metabolism in human liver microsomes. (2001). https://pubmed.ncbi.nlm.nih.gov/11317475/ DOI: 10.1007/s002280000245
Complete structured claim and evidence
DIM increased CYP1A2 protein in cultured human liver slices.
3,3'-Diindolylmethane / DIM → Human cytochrome P450 1A2 source_derived_draftungraded
Experimental context and source evidence
evidence_span
{"source_cache": "artifacts/dim-research/9741959.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "11eec60fad1ec0e18085a59f90fa3237235bb0614b5ee2b29058757e3b45ba47", "start_char": 0, "end_char": 1338, "text_sha256": "11eec60fad1ec0e18085a59f90fa3237235bb0614b5ee2b29058757e3b45ba47"}
experimental_model
Precision-cut liver-slice induction and immunoblotting
exposure
DIM 50 micromolar for 72 hours
limitations
Ex-vivo exposure; not a measured oral DIM effect on a patient drug concentration. Four donors showed variable responses.
nutrient_topic
Diindolylmethane (DIM) research collection; topical membership is not evidence of a direct dietary effect. · 3,3'-Diindolylmethane / DIM
organism
Human donor liver slices
plain_language
Human liver tissue can make more of this enzyme after DIM exposure.
primary_references
[dim-p9741959] 3,3'-Diindolylmethane induces CYP1A2 in cultured precision-cut human liver slices. (1998). https://pubmed.ncbi.nlm.nih.gov/9741959/ DOI: 10.1080/004982598239227
tissue_or_cell_type
CYP1A proteins and catalytic assays
Diindolylmethane (DIM): formation, receptor signaling, metabolism and drug interactions (2026-09-17) · lines 350–361
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Precision-cut liver-slice induction and immunoblotting · source_derived_draft · unverified_draft
### dim-liver-cyp1a2 DIM increased CYP1A2 protein in cultured human liver slices. Condition category: normal nutrient_topic: Diindolylmethane (DIM) research collection; topical membership is not evidence of a direct dietary effect. plain_language: Human liver tissue can make more of this enzyme after DIM exposure. organism: Human donor liver slices tissue_or_cell_type: CYP1A proteins and catalytic assays experimental_model: Precision-cut liver-slice induction and immunoblotting limitations: Ex-vivo exposure; not a measured oral DIM effect on a patient drug concentration. Four donors showed variable responses. exposure: DIM 50 micromolar for 72 hours evidence_span: {"source_cache": "artifacts/dim-research/9741959.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "11eec60fad1ec0e18085a59f90fa3237235bb0614b5ee2b29058757e3b45ba47", "start_char": 0, "end_char": 1338, "text_sha256": "11eec60fad1ec0e18085a59f90fa3237235bb0614b5ee2b29058757e3b45ba47"} [dim-p9741959] 3,3'-Diindolylmethane induces CYP1A2 in cultured precision-cut human liver slices. (1998). https://pubmed.ncbi.nlm.nih.gov/9741959/ DOI: 10.1080/004982598239227
Complete structured claim and evidence
DIM directly inhibited CYP1A2 catalytic activity in the tested enzyme assay.
3,3'-Diindolylmethane / DIM → Human cytochrome P450 1A2 source_derived_draftungraded
Experimental context and source evidence
evidence_span
{"source_cache": "artifacts/dim-research/19770484.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "b5956f74860b0cd89114dab4179908bae1a59aab65220ac0421f4c5365bed6ba", "start_char": 0, "end_char": 1446, "text_sha256": "b5956f74860b0cd89114dab4179908bae1a59aab65220ac0421f4c5365bed6ba"}
experimental_model
Pretreatment versus cotreatment, adduct and recombinant-enzyme assays
exposure
DIM pretreatment for 48 hours; direct catalytic assays separately
limitations
Induction over time and direct inhibition are distinct mechanisms. Aflatoxin assay effects do not establish human cancer incidence or net disposition of unrelated drugs.
nutrient_topic
Diindolylmethane (DIM) research collection; topical membership is not evidence of a direct dietary effect. · 3,3'-Diindolylmethane / DIM
organism
Primary human hepatocytes and human enzyme preparations
plain_language
Direct enzyme inhibition can oppose a slower increase in enzyme production.
primary_references
[dim-p19770484] Modulation of aflatoxin B1-mediated genotoxicity in primary cultures of human hepatocytes by diindolylmethane, curcumin, and xanthohumols. (2009). https://pubmed.ncbi.nlm.nih.gov/19770484/ DOI: 10.1093/toxsci/kfp206
tissue_or_cell_type
Aflatoxin metabolism and CYP catalytic activity
Diindolylmethane (DIM): formation, receptor signaling, metabolism and drug interactions (2026-09-17) · lines 441–452
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Pretreatment versus cotreatment, adduct and recombinant-enzyme assays · source_derived_draft · unverified_draft
### dim-cyp1a2-direct-inhibition DIM directly inhibited CYP1A2 catalytic activity in the tested enzyme assay. Condition category: normal nutrient_topic: Diindolylmethane (DIM) research collection; topical membership is not evidence of a direct dietary effect. plain_language: Direct enzyme inhibition can oppose a slower increase in enzyme production. organism: Primary human hepatocytes and human enzyme preparations tissue_or_cell_type: Aflatoxin metabolism and CYP catalytic activity experimental_model: Pretreatment versus cotreatment, adduct and recombinant-enzyme assays limitations: Induction over time and direct inhibition are distinct mechanisms. Aflatoxin assay effects do not establish human cancer incidence or net disposition of unrelated drugs. exposure: DIM pretreatment for 48 hours; direct catalytic assays separately evidence_span: {"source_cache": "artifacts/dim-research/19770484.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "b5956f74860b0cd89114dab4179908bae1a59aab65220ac0421f4c5365bed6ba", "start_char": 0, "end_char": 1446, "text_sha256": "b5956f74860b0cd89114dab4179908bae1a59aab65220ac0421f4c5365bed6ba"} [dim-p19770484] Modulation of aflatoxin B1-mediated genotoxicity in primary cultures of human hepatocytes by diindolylmethane, curcumin, and xanthohumols. (2009). https://pubmed.ncbi.nlm.nih.gov/19770484/ DOI: 10.1093/toxsci/kfp206
Complete structured claim and evidence
Mangiferin reduced measured CYP1A2 activity in the hepatocyte experiment.
Mangiferin → Human cytochrome P450 1A2 source_derived_draftungraded
Experimental context and source evidence
evidence_span
{"source_cache": "artifacts/mangiferin-research/22815239.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "e85ebd0af89f030dbeda45ed922e93a8a616c51f5ce1b64badc44d90791716c0", "start_char": 0, "end_char": 1728, "text_sha256": "e85ebd0af89f030dbeda45ed922e93a8a616c51f5ce1b64badc44d90791716c0"}
experimental_model
Primary human hepatocyte exposure
exposure
Mangiferin 50-250 micrograms/mL for 48 hours
limitations
High in vitro concentrations; decreased enzyme activity is not proof of human drug-level changes. Extract and isolated mangiferin are distinct.
nutrient_topic
Mangiferin research collection; topical membership is not evidence of a direct dietary effect. · Mangiferin
organism
Homo sapiens
plain_language
A drug-metabolizing enzyme was inhibited under the tested exposure.
primary_references
[mangiferin-p22815239] Mangifera indica L. extract and mangiferin modulate cytochrome P450 and UDP-glucuronosyltransferase enzymes in primary cultures of human hepatocytes. (2013). https://pubmed.ncbi.nlm.nih.gov/22815239/ DOI: 10.1002/ptr.4782
tissue_or_cell_type
Cultured hepatocytes
Mangiferin: metabolism, signaling and nutrient connections (2026-09-17) · lines 770–781
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Primary human hepatocyte exposure · source_derived_draft · unverified_draft
### mangiferin-cyp1a2-activity Mangiferin reduced measured CYP1A2 activity in the hepatocyte experiment. Condition category: normal nutrient_topic: Mangiferin research collection; topical membership is not evidence of a direct dietary effect. plain_language: A drug-metabolizing enzyme was inhibited under the tested exposure. organism: Homo sapiens tissue_or_cell_type: Cultured hepatocytes experimental_model: Primary human hepatocyte exposure limitations: High in vitro concentrations; decreased enzyme activity is not proof of human drug-level changes. Extract and isolated mangiferin are distinct. exposure: Mangiferin 50-250 micrograms/mL for 48 hours evidence_span: {"source_cache": "artifacts/mangiferin-research/22815239.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "e85ebd0af89f030dbeda45ed922e93a8a616c51f5ce1b64badc44d90791716c0", "start_char": 0, "end_char": 1728, "text_sha256": "e85ebd0af89f030dbeda45ed922e93a8a616c51f5ce1b64badc44d90791716c0"} [mangiferin-p22815239] Mangifera indica L. extract and mangiferin modulate cytochrome P450 and UDP-glucuronosyltransferase enzymes in primary cultures of human hepatocytes. (2013). https://pubmed.ncbi.nlm.nih.gov/22815239/ DOI: 10.1002/ptr.4782
Complete structured claim and evidence
MOCOS defects in type II xanthinuria support its role in supplying the terminal sulfur required by XDH and AOX1.
Human molybdenum cofactor sulfurase / MOCOS → Human xanthine oxidoreductase / XDH source_derived_draftungraded
Experimental context and source evidence
evidence_span
{"source_cache": "artifacts/molybdenum-research/11302742.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "8f595c96d16b055cd6b9611c4d036626222ffb084ec778f840255cac57ecdfb3", "start_char": 0, "end_char": 1011, "text_sha256": "8f595c96d16b055cd6b9611c4d036626222ffb084ec778f840255cac57ecdfb3"}
experimental_model
Gene identification in two type II xanthinuria patients and comparison subjects
exposure
MOCOS Arg419 stop mutation
limitations
Genetic evidence for terminal sulfuration; type II xanthinuria is different from loss of all Moco synthesis.
nutrient_topic
Molybdenum research collection; topical membership is not evidence of a direct dietary effect. · Molybdenum
organism
Homo sapiens
plain_language
Two molybdenum enzymes need an additional sulfur-activation step.
primary_references
[mo-p11302742] Mutation of human molybdenum cofactor sulfurase gene is responsible for classical xanthinuria type II. (2001). https://pubmed.ncbi.nlm.nih.gov/11302742/ DOI: 10.1006/bbrc.2001.4719
tissue_or_cell_type
Liver cDNA and patient genetics
Molybdenum: cofactor assembly, sulfur metabolism and nutrient interactions (2026-09-17) · lines 521–532
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Gene identification in two type II xanthinuria patients and comparison subjects · source_derived_draft · unverified_draft
### mo-mocos-sulfuration MOCOS defects in type II xanthinuria support its role in supplying the terminal sulfur required by XDH and AOX1. Condition category: normal nutrient_topic: Molybdenum research collection; topical membership is not evidence of a direct dietary effect. plain_language: Two molybdenum enzymes need an additional sulfur-activation step. organism: Homo sapiens tissue_or_cell_type: Liver cDNA and patient genetics experimental_model: Gene identification in two type II xanthinuria patients and comparison subjects limitations: Genetic evidence for terminal sulfuration; type II xanthinuria is different from loss of all Moco synthesis. exposure: MOCOS Arg419 stop mutation evidence_span: {"source_cache": "artifacts/molybdenum-research/11302742.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "8f595c96d16b055cd6b9611c4d036626222ffb084ec778f840255cac57ecdfb3", "start_char": 0, "end_char": 1011, "text_sha256": "8f595c96d16b055cd6b9611c4d036626222ffb084ec778f840255cac57ecdfb3"} [mo-p11302742] Mutation of human molybdenum cofactor sulfurase gene is responsible for classical xanthinuria type II. (2001). https://pubmed.ncbi.nlm.nih.gov/11302742/ DOI: 10.1006/bbrc.2001.4719
Complete structured claim and evidence
The purified human MOCOS NifS-like domain bound PLP and exhibited cysteine desulfurase activity.
PLP → Human molybdenum cofactor sulfurase / MOCOS source_derived_draftungraded
Experimental context and source evidence
evidence_span
{"source_cache": "artifacts/molybdenum-research/34356852.fulltext.txt", "locator": "Exact primary full-text span; zero-based, end-exclusive Unicode character offsets", "file_sha256": "8bf3a09c4f88994cf8adc50faf391e62ac27e7572e59e6606147f2c689212d07", "start_char": 41304, "end_char": 42029, "text_sha256": "b9b02aae5eb537bdffc178ceaa33177cef6448738c19cb1a8477ad543f4e970c"}
experimental_model
Xanthinuria families with recombinant human MOCOS-domain assays and a plant XDH homolog assay
exposure
PLP quantification, cysteine desulfurase assays and Moco/MPT binding
limitations
Human XDH C150F was functionally modeled using Arabidopsis XDH1 C161S, not purified human C150F; MOCOS assays used isolated domains.
nutrient_topic
Molybdenum research collection; topical membership is not evidence of a direct dietary effect. · Molybdenum
organism
Human genetics and human MOCOS proteins; plant XDH variant experiment separately
plain_language
Vitamin B6 chemistry helps supply the sulfur used to activate these molybdenum enzymes.
primary_references
[mo-p34356852] Classical Xanthinuria in Nine Israeli Families and Two Isolated Cases from Germany: Molecular, Biochemical and Population Genetics Aspects. (2021). https://pubmed.ncbi.nlm.nih.gov/34356852/ DOI: 10.3390/biomedicines9070788
tissue_or_cell_type
Patient samples and purified domains
Molybdenum: cofactor assembly, sulfur metabolism and nutrient interactions (2026-09-17) · lines 534–545
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Xanthinuria families with recombinant human MOCOS-domain assays and a plant XDH homolog assay · source_derived_draft · unverified_draft
### mo-mocos-plp The purified human MOCOS NifS-like domain bound PLP and exhibited cysteine desulfurase activity. Condition category: normal nutrient_topic: Molybdenum research collection; topical membership is not evidence of a direct dietary effect. plain_language: Vitamin B6 chemistry helps supply the sulfur used to activate these molybdenum enzymes. organism: Human genetics and human MOCOS proteins; plant XDH variant experiment separately tissue_or_cell_type: Patient samples and purified domains experimental_model: Xanthinuria families with recombinant human MOCOS-domain assays and a plant XDH homolog assay limitations: Human XDH C150F was functionally modeled using Arabidopsis XDH1 C161S, not purified human C150F; MOCOS assays used isolated domains. exposure: PLP quantification, cysteine desulfurase assays and Moco/MPT binding evidence_span: {"source_cache": "artifacts/molybdenum-research/34356852.fulltext.txt", "locator": "Exact primary full-text span; zero-based, end-exclusive Unicode character offsets", "file_sha256": "8bf3a09c4f88994cf8adc50faf391e62ac27e7572e59e6606147f2c689212d07", "start_char": 41304, "end_char": 42029, "text_sha256": "b9b02aae5eb537bdffc178ceaa33177cef6448738c19cb1a8477ad543f4e970c"} [mo-p34356852] Classical Xanthinuria in Nine Israeli Families and Two Isolated Cases from Germany: Molecular, Biochemical and Population Genetics Aspects. (2021). https://pubmed.ncbi.nlm.nih.gov/34356852/ DOI: 10.3390/biomedicines9070788
Complete structured claim and evidence

Availability and dependencies

Each situation shows the normal role first, then what the sources report under a specific condition. A shortfall in the diet, a fault in the machinery, and a low blood reading are kept separate because they are not the same thing.

A2A receptor loss removes caffeine-induced wakefulness in mice

Condition: machinery_impairment · Loss of the specified receptor in the knockout model.

Normal role: Intact receptor machinery allows the measured wild-type response.

Recorded consequence: Wakefulness did not increase after caffeine in A2A-knockout mice.

Scope: Mouse mechanism experiment.

A1 receptor loss removes the mouse renal response

Condition: machinery_impairment · Loss of the specified receptor in the knockout model.

Normal role: Intact receptor machinery allows the measured wild-type response.

Recorded consequence: Caffeine-induced diuresis and natriuresis were absent in the knockout comparison.

Scope: Mouse mechanism experiment.

The sources

Every document behind this chapter is preserved word for word. Open one to read it in full with its recorded conflicts marked in place.

Berberine: metabolism, nutrient connections and drug interactions (2026-09-17)AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · unverified_draftRead preserved source
Boron: chemistry, nutrient interactions, low-intake studies and mechanistic uncertainties (2026-09-17)AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · unverified_draftRead preserved source
Caffeine: receptors, metabolism, nutrient interactions, adaptation and discovery questions (2026-09-18)AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · unverified_draftRead preserved source
Calcium: mechanism-first literature curation (2026-09-17)AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · unverified_draftRead preserved source
Diindolylmethane (DIM): formation, receptor signaling, metabolism and drug interactions (2026-09-17)AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · unverified_draftRead preserved source
L-Theanine: metabolism, neural signaling, nutrient connections and human outcomes (2026-09-17)AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · unverified_draftRead preserved source
Mangiferin: metabolism, signaling and nutrient connections (2026-09-17)AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · unverified_draftRead preserved source
Melatonin: synthesis, receptors, circadian timing and nutrient interactions (2026-09-17)AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · unverified_draftRead preserved source
Molybdenum: cofactor assembly, sulfur metabolism and nutrient interactions (2026-09-17)AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · unverified_draftRead preserved source
Vitamin D2 and D3: mechanisms, deficiency and nutrient interactions (2026-09-17)AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · unverified_draftRead preserved source

Recorded disagreements

Where two sources say different things, both are kept and the difference is explained. You can discuss a disagreement or propose a mechanism that might account for it.

Open questions in this collection

Questions the curators could not answer from the sources in front of them, kept here with the reason each one is still open. These are gaps in this collection, not findings or proof that no one has studied them.

Chapters are assembled from supplied drafts and curated literature summaries. Statements remain unverified against the primary studies, and the ledger is not medical advice.

Evidence, AI assistance and curation standards

Caffeine

The mechanisms

Caffeine displaced 5–44% of the A1 PET ligand signal; modeled half-maximal displacement corresponded to plasma caffeine of 67 micromolar.

Crystallography resolved caffeine in a thermostabilized A2A receptor with an inactive-state conformation.

Caffeine at 5, 10 and 15 mg/kg increased wakefulness in wild-type and A1-knockout mice, but not A2A-knockout mice.

Injected caffeine increased locomotion only in mice expressing A2A receptors; ingestion also produced an A2A-dependent increase in males.

Caffeine ingestion increased oxygen consumption in wild-type mice, with smaller responses in receptor-knockout groups.

Injected caffeine at 30 mg/kg lowered body temperature, especially in receptor-knockout mice, suggesting an effect beyond A1/A2A blockade.

Caffeine 300 mg increased D2/D3 PET availability in putamen and ventral striatum, but not caudate, in 20 healthy participants.

Caffeine three hours before habitual bedtime delayed the human melatonin rhythm by approximately 40 minutes.

Caffeine lengthened the circadian reporter period dose-dependently in U2OS cells.

A cAMP biosensor detected increased cAMP; pharmacological and knockdown experiments supported adenosine-receptor signaling rather than RyR or PDE perturbation as sufficient to explain the clock effect.

A fixed 400 mg dose at bedtime, three hours before, or six hours before increased sleep disturbance relative to placebo.

At 24 hours after placebo substitution, withdrawal increased middle- and anterior-cerebral arterial flow velocities.

Acute withdrawal increased EEG theta power.

Acute withdrawal decreased EEG beta-2 power.

Withdrawal increased tiredness/fatigue ratings and decreased energy/vigor ratings.

Tolerance occurred on subjective measures but not the measured physiological endpoints; chronic effects remained mainly on EEG beta-2 power.

Repeated caffeine exposure increased neutrophil A2A receptor binding density.

After caffeine exposure, NECA stimulation produced greater cAMP accumulation.

NECA-stimulated adapted neutrophils showed lower superoxide production; binding and functional changes returned to baseline after 48 hours withdrawal.

Caffeine N3-demethylation produced the specified dimethylxanthine; fluvoxamine reduced its formation clearance.

Caffeine N1-demethylation produced the specified dimethylxanthine; fluvoxamine reduced its formation clearance.

Caffeine N7-demethylation produced the specified dimethylxanthine; fluvoxamine reduced its formation clearance.

Median caffeine clearance fell from 107 to 21 mL/min during fluvoxamine treatment.

Caffeine half-life increased from five to 31 hours in the fluvoxamine crossover experiment.

In human liver microsomes, fluvoxamine inhibited caffeine demethylated-metabolite formation with Ki values of 0.08–0.28 micromolar.

Inhibitor experiments supported CYP3A4 involvement in caffeine 8-hydroxylation to trimethyluric acid.

Allopurinol specifically and dose-dependently inhibited conversion of caffeine-derived 1-methylxanthine to 1-methyluric acid.

In 21 participants, allopurinol reduced urinary 1-methyluric-acid/1-methylxanthine to 15.9% of baseline.

The NAT2 ratio AFMU/1MX fell to 56.7%, an alternative combined-metabolite NAT2 ratio stayed constant, and a CYP1A2 ratio transiently rose to 167%.

Women using oral contraceptives had caffeine half-life 10.7 versus 6.2 hours and lower clearance than women not using them.

Dose-normalized serum caffeine rose between first and third trimester in a 59-woman study; theophylline concentrations also rose.

Caffeine coadministration increased mean clozapine AUC by 19% in the crossover experiment.

Mean clozapine oral clearance fell 14%; metabolite-to-parent ratios also fell during caffeine exposure.

Calcium reabsorption fell from 98.6% to 97.5%, with no significant change in filtered calcium load.

Magnesium reabsorption fell from 97.0% to 94.2%, with no significant change in filtered magnesium load.

Urinary calcium/creatinine rose from 120 to 200 mg/g.

Urinary magnesium/creatinine rose from 70 to 110 mg/g.

Urinary sodium/creatinine rose from 3800 to 6200 mg/g.

Urinary chloride/creatinine rose from 9200 to 14800 mg/g.

Total potassium output increased over the two-hour post-caffeine collection.

Later nighttime conservation did not fully offset earlier loss; net 24-hour urinary excretion increased by 0.32 mmol.

Later nighttime conservation did not fully offset earlier loss; net 24-hour urinary excretion increased by 0.16 mmol.

An 800 mg total caffeine gum regimen increased renal calcium clearance by 77%; changes correlated with sodium clearance and urine volume.

Caffeine 45 mg/kg caused diuresis and natriuresis in wild-type but not A1-knockout mice.

In 50 habitual male coffee drinkers, coffee and water produced no significant difference in total body water or 24-hour urine volume.

Millimolar caffeine activated the skeletal-muscle ryanodine-receptor system; xanthine substitution altered ryanodine binding.

Caffeine inhibited IP3-gated channels with half-inhibition at 1.64 mM; 5 mM reduced opening frequency more than threefold without changing conductance.

Increasing IP3 overcame inhibition, but caffeine did not reduce specific IP3 binding to the receptor.

Caffeine inhibited measured cAMP-PDE activity by up to about 40% at 250–500 micrograms/mL in the reported assay.

Caffeine inhibited the checkpoint kinase at concentrations associated with experimental radiosensitization.

Caffeine inhibited the checkpoint kinase at concentrations associated with experimental radiosensitization.

Caffeine-treated irradiated A549 cells failed G2 arrest and showed radioresistant DNA synthesis after S-phase irradiation.

Caffeine reduced radiation-induced p53 Ser15 phosphorylation; DNA-PK was resistant and Chk1 only marginally inhibited in the comparison.

Creatine alone and creatine plus caffeine each increased muscle phosphocreatine by 4–6%; measured ATP stayed constant.

Creatine increased dynamic torque by 10–23%, whereas the creatine-plus-caffeine regimen did not improve torque.

Four days of creatine shortened stimulated-muscle relaxation time by about 5%.

Three days of caffeine 5 mg/kg/day prolonged relaxation time by about 10%; acute caffeine and the creatine/caffeine combination did not significantly change it.

A single caffeine dose after five days of creatine loading increased mean and peak cycling power over creatine-plus-placebo during sprints 1 and 2.

Caffeine increased plasma epinephrine with or without propranolol.

Insulin and C-peptide areas were 42% and 39% greater with caffeine, while blood glucose was similar among trials.

With propranolol, caffeine-associated insulin and C-peptide responses resembled placebo.

At 36 weeks postmenstrual age, 36% of surviving caffeine-group infants required oxygen versus 47% with placebo; adjusted odds ratio 0.63.

Positive airway pressure ended at median 31 weeks postmenstrual age versus 32 weeks with placebo.

Weight gain was temporarily lower, with the greatest mean difference −23 g at two weeks.

Calcium binds an activating RyR1 site and primes gating; ATP and caffeine increase open-state representation in the experimental preparation.

Significant inhibition of caffeine-evoked calcium release required 20 µM boric acid in LNCaP cells and 150 µM in non-tumor PWR1E cells.

Caffeine-derived CYP1A2 indices correlated with clozapine clearance in the 14-person study.

The paraxanthine-to-caffeine ratio was used to phenotype CYP1A2 during smoking cessation.

Caffeine clearance fell by 36.1% after cessation; the fitted half-life of CYP1A2 activity decline was 38.6 hours.

Nicotine patches did not significantly change caffeine pharmacokinetics or metabolite formation in the crossover study.

I3C increased caffeine-probed CYP1A2 activity in 94% of participants in the phase I study.

No statistically significant change in caffeine probe pharmacokinetics was found after berberine.

The theanine-caffeine combination improved simple reaction time in the acute crossover experiment.

Theanine improved visual recognition reaction time in this small acute study; caffeine and the combination also improved it.

Theanine attenuated the caffeine-associated blood-pressure response in the experiment.

Theanine did not significantly reduce caffeine-associated jitteriness in the same experiment.

Concurrent caffeine raised melatonin peak concentration by 142% and AUC by 120% on average.

Crystallography and extracted-flavin analysis identified FAD bound to recombinant human POR.