Pyridoxine

experimental_model

Differentiated human SH-SY5Y and CaCo-2 cells; isolated enzyme assays

exposure

Pyridoxine 0-5 micromolar for 24 hours.

exposure-class

Experimental excess pyridoxine; not dietary B6 deficiency · Pyridoxine

limitations

Tumor-derived cells and MTT endpoint; no oral-dose conversion or human toxicity threshold.

nutrient_topic

Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6

organism

Homo sapiens

plain_language

Added pyridoxine harmed this experimental neuronal cell model.

primary_references

[vrolijk-2017-pn] The vitamin B6 paradox: Supplementation with high concentrations of pyridoxine leads to decreased vitamin B6 function (2017). https://doi.org/10.1016/j.tiv.2017.07.009 DOI: 10.1016/j.tiv.2017.07.009

tissue_or_cell_type

Differentiated SH-SY5Y neuroblastoma cells

Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1232–1243

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Differentiated human SH-SY5Y and CaCo-2 cells; isolated enzyme assays · source_derived_draft · unverified_draft

### b6-neuro-pn-cell-viability Pyridoxine reduced MTT-measured viability of differentiated SH-SY5Y cells after 24 hours in a concentration-dependent manner. Condition category: normal nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Added pyridoxine harmed this experimental neuronal cell model. organism: Homo sapiens tissue_or_cell_type: Differentiated SH-SY5Y neuroblastoma cells experimental_model: Differentiated human SH-SY5Y and CaCo-2 cells; isolated enzyme assays limitations: Tumor-derived cells and MTT endpoint; no oral-dose conversion or human toxicity threshold. exposure: Pyridoxine 0-5 micromolar for 24 hours. exposure-class: Experimental excess pyridoxine; not dietary B6 deficiency [vrolijk-2017-pn] The vitamin B6 paradox: Supplementation with high concentrations of pyridoxine leads to decreased vitamin B6 function (2017). https://doi.org/10.1016/j.tiv.2017.07.009 DOI: 10.1016/j.tiv.2017.07.009

experimental_model

Differentiated human SH-SY5Y and CaCo-2 cells; isolated enzyme assays

exposure

5 micromolar pyridoxine; commercial Streptococcus faecalis enzyme (current Enterococcus name).

exposure-class

Experimental excess pyridoxine; not dietary B6 deficiency · Pyridoxine

limitations

Not human GAD, DDC or PDXK; mechanism of human neuropathy remains unresolved.

nutrient_topic

Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6

organism

Enterococcus faecalis (reported as Streptococcus faecalis)

plain_language

Pyridoxine interfered with one isolated B6-dependent enzyme.

primary_references

[vrolijk-2017-pn] The vitamin B6 paradox: Supplementation with high concentrations of pyridoxine leads to decreased vitamin B6 function (2017). https://doi.org/10.1016/j.tiv.2017.07.009 DOI: 10.1016/j.tiv.2017.07.009

tissue_or_cell_type

Cell-free bacterial enzyme

Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1258–1269

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Differentiated human SH-SY5Y and CaCo-2 cells; isolated enzyme assays · source_derived_draft · unverified_draft

### b6-neuro-pn-enzyme-inhibition Pyridoxine inhibited the tested PLP-dependent bacterial tyrosine decarboxylase preparation. Condition category: normal nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Pyridoxine interfered with one isolated B6-dependent enzyme. organism: Enterococcus faecalis (reported as Streptococcus faecalis) tissue_or_cell_type: Cell-free bacterial enzyme experimental_model: Differentiated human SH-SY5Y and CaCo-2 cells; isolated enzyme assays limitations: Not human GAD, DDC or PDXK; mechanism of human neuropathy remains unresolved. exposure: 5 micromolar pyridoxine; commercial Streptococcus faecalis enzyme (current Enterococcus name). exposure-class: Experimental excess pyridoxine; not dietary B6 deficiency [vrolijk-2017-pn] The vitamin B6 paradox: Supplementation with high concentrations of pyridoxine leads to decreased vitamin B6 function (2017). https://doi.org/10.1016/j.tiv.2017.07.009 DOI: 10.1016/j.tiv.2017.07.009

availability_state

Experimental excess, not nutrient deficiency

experimental_model

Five healthy volunteers prospectively followed during experimental pyridoxine excess.

exposure

Pyridoxine 1 or 3 g/day, stopped with clinical/laboratory abnormality; very high historical exposures.

limitations

Five volunteers at gram doses; cannot determine a lowest toxic dose, safe upper intake or equivalence of different B6 forms.

nutrient_topic

Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6

organism

Homo sapiens

plain_language

At very high exposure, more pyridoxine produced earlier sensory toxicity.

primary_references

[b6-berger1992] Dose response, coasting, and differential fiber vulnerability in human toxic neuropathy: a prospective study of pyridoxine neurotoxicity (1992). https://pubmed.ncbi.nlm.nih.gov/1620347/ DOI: 10.1212/wnl.42.7.1367

tissue_or_cell_type

Peripheral sensory function

Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1559–1570

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Five healthy volunteers prospectively followed during experimental pyridoxine excess. · source_derived_draft · unverified_draft

### b6-pyridoxine-dose-latency All five volunteers developed sensory symptoms and quantitative sensory abnormalities; the 3 g/day group became symptomatic sooner than the 1 g/day group. Condition category: normal nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: At very high exposure, more pyridoxine produced earlier sensory toxicity. organism: Homo sapiens tissue_or_cell_type: Peripheral sensory function experimental_model: Five healthy volunteers prospectively followed during experimental pyridoxine excess. limitations: Five volunteers at gram doses; cannot determine a lowest toxic dose, safe upper intake or equivalence of different B6 forms. exposure: Pyridoxine 1 or 3 g/day, stopped with clinical/laboratory abnormality; very high historical exposures. availability_state: Experimental excess, not nutrient deficiency [b6-berger1992] Dose response, coasting, and differential fiber vulnerability in human toxic neuropathy: a prospective study of pyridoxine neurotoxicity (1992). https://pubmed.ncbi.nlm.nih.gov/1620347/ DOI: 10.1212/wnl.42.7.1367

availability_state

biomarker_context Imported condition classification; unverified.

experimental_model

Double-blind randomized placebo-controlled RA trial: 36 recruited, 33 baseline completers, 28 low-PLP patients eligible for supplementation.

exposure

Pyridoxine hydrochloride 50 mg/day or placebo for 30 days; historical trial exposure, not a regimen recommendation.

limitations

Challenge tests and erythrocyte saturation do not identify every tissue defect.

nutrient_topic

Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6

organism

Homo sapiens

plain_language

Two B6-related functional tests improved, alongside blood vitamin levels.

primary_references

[b6-chiang2005-trial] Pyridoxine supplementation corrects vitamin B6 deficiency but does not improve inflammation in patients with rheumatoid arthritis (2005). https://pubmed.ncbi.nlm.nih.gov/16277693/ DOI: 10.1186/ar1839

tissue_or_cell_type

Human blood and whole-body measurements

trigger_kind

biomarker_context Imported condition classification; unverified.

Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1473–1483

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Double-blind randomized placebo-controlled RA trial: 36 recruited, 33 baseline completers, 28 low-PLP patients eligible for supplementation. · source_derived_draft · unverified_draft

### b6-ra-functional-tests Pyridoxine reduced the erythrocyte AST activation coefficient and improved post-tryptophan-load urinary xanthurenate response. Condition category: biomarker_context nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Two B6-related functional tests improved, alongside blood vitamin levels. organism: Homo sapiens tissue_or_cell_type: Human blood and whole-body measurements experimental_model: Double-blind randomized placebo-controlled RA trial: 36 recruited, 33 baseline completers, 28 low-PLP patients eligible for supplementation. limitations: Challenge tests and erythrocyte saturation do not identify every tissue defect. exposure: Pyridoxine hydrochloride 50 mg/day or placebo for 30 days; historical trial exposure, not a regimen recommendation. [b6-chiang2005-trial] Pyridoxine supplementation corrects vitamin B6 deficiency but does not improve inflammation in patients with rheumatoid arthritis (2005). https://pubmed.ncbi.nlm.nih.gov/16277693/ DOI: 10.1186/ar1839

availability_state

biomarker_context Imported condition classification; unverified.

cross_nutrient

Methionine handling depends on more than circulating B6.

experimental_model

Double-blind randomized placebo-controlled RA trial: 36 recruited, 33 baseline completers, 28 low-PLP patients eligible for supplementation.

exposure

Pyridoxine hydrochloride 50 mg/day or placebo for 30 days; historical trial exposure, not a regimen recommendation.

limitations

Subgroup findings are exploratory; methotrexate, inflammation and enzyme differences can affect the challenge.

nutrient_topic

Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6

organism

Homo sapiens

plain_language

The homocysteine test did not improve as consistently as the other B6 tests.

primary_references

[b6-chiang2005-trial] Pyridoxine supplementation corrects vitamin B6 deficiency but does not improve inflammation in patients with rheumatoid arthritis (2005). https://pubmed.ncbi.nlm.nih.gov/16277693/ DOI: 10.1186/ar1839

tissue_or_cell_type

Human blood and whole-body measurements

trigger_kind

biomarker_context Imported condition classification; unverified.

Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1497–1508

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Double-blind randomized placebo-controlled RA trial: 36 recruited, 33 baseline completers, 28 low-PLP patients eligible for supplementation. · source_derived_draft · unverified_draft

### b6-ra-homocysteine-response-boundary The overall post-methionine homocysteine treatment effect was a nonsignificant trend (P=0.086); an elevated-baseline subgroup showed a stronger signal. Condition category: biomarker_context nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: The homocysteine test did not improve as consistently as the other B6 tests. organism: Homo sapiens tissue_or_cell_type: Human blood and whole-body measurements experimental_model: Double-blind randomized placebo-controlled RA trial: 36 recruited, 33 baseline completers, 28 low-PLP patients eligible for supplementation. limitations: Subgroup findings are exploratory; methotrexate, inflammation and enzyme differences can affect the challenge. exposure: Pyridoxine hydrochloride 50 mg/day or placebo for 30 days; historical trial exposure, not a regimen recommendation. cross_nutrient: Methionine handling depends on more than circulating B6. [b6-chiang2005-trial] Pyridoxine supplementation corrects vitamin B6 deficiency but does not improve inflammation in patients with rheumatoid arthritis (2005). https://pubmed.ncbi.nlm.nih.gov/16277693/ DOI: 10.1186/ar1839

availability_state

biomarker_context Imported condition classification; unverified.

experimental_model

Double-blind randomized placebo-controlled RA trial: 36 recruited, 33 baseline completers, 28 low-PLP patients eligible for supplementation.

exposure

Pyridoxine hydrochloride 50 mg/day or placebo for 30 days; historical trial exposure, not a regimen recommendation.

limitations

Small short trial; a null finding is not proof that no population can respond. The CRP/ESR/RF table-versus-narrative reporting ambiguity is retained separately as an open question.

nutrient_topic

Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6

organism

Homo sapiens

plain_language

Correcting the vitamin measurements did not resolve the measured inflammation.

primary_references

[b6-chiang2005-trial] Pyridoxine supplementation corrects vitamin B6 deficiency but does not improve inflammation in patients with rheumatoid arthritis (2005). https://pubmed.ncbi.nlm.nih.gov/16277693/ DOI: 10.1186/ar1839

tissue_or_cell_type

Human blood and whole-body measurements

trigger_kind

biomarker_context Imported condition classification; unverified.

Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1485–1495

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Double-blind randomized placebo-controlled RA trial: 36 recruited, 33 baseline completers, 28 low-PLP patients eligible for supplementation. · source_derived_draft · unverified_draft

### b6-ra-no-cytokine-suppression The 2005 trial found no suppression of IL-6 or TNF production despite improved B6 markers. Condition category: biomarker_context nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Correcting the vitamin measurements did not resolve the measured inflammation. organism: Homo sapiens tissue_or_cell_type: Human blood and whole-body measurements experimental_model: Double-blind randomized placebo-controlled RA trial: 36 recruited, 33 baseline completers, 28 low-PLP patients eligible for supplementation. limitations: Small short trial; a null finding is not proof that no population can respond. The CRP/ESR/RF table-versus-narrative reporting ambiguity is retained separately as an open question. exposure: Pyridoxine hydrochloride 50 mg/day or placebo for 30 days; historical trial exposure, not a regimen recommendation. [b6-chiang2005-trial] Pyridoxine supplementation corrects vitamin B6 deficiency but does not improve inflammation in patients with rheumatoid arthritis (2005). https://pubmed.ncbi.nlm.nih.gov/16277693/ DOI: 10.1186/ar1839

availability_state

biomarker_context Imported condition classification; unverified.

experimental_model

Double-blind randomized placebo-controlled RA trial: 36 recruited, 33 baseline completers, 28 low-PLP patients eligible for supplementation.

exposure

Pyridoxine hydrochloride 50 mg/day or placebo for 30 days; historical trial exposure, not a regimen recommendation.

limitations

Selected low-PLP RA patients; blood response is not direct all-organ cofactor measurement.

nutrient_topic

Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6

organism

Homo sapiens

plain_language

The measured B6 pools responded to added pyridoxine.

primary_references

[b6-chiang2005-trial] Pyridoxine supplementation corrects vitamin B6 deficiency but does not improve inflammation in patients with rheumatoid arthritis (2005). https://pubmed.ncbi.nlm.nih.gov/16277693/ DOI: 10.1186/ar1839

tissue_or_cell_type

Human blood and whole-body measurements

trigger_kind

biomarker_context Imported condition classification; unverified.

Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1461–1471

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Double-blind randomized placebo-controlled RA trial: 36 recruited, 33 baseline completers, 28 low-PLP patients eligible for supplementation. · source_derived_draft · unverified_draft

### b6-ra-vitamer-response Supplementation improved plasma and erythrocyte PLP compared with placebo. Condition category: biomarker_context nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: The measured B6 pools responded to added pyridoxine. organism: Homo sapiens tissue_or_cell_type: Human blood and whole-body measurements experimental_model: Double-blind randomized placebo-controlled RA trial: 36 recruited, 33 baseline completers, 28 low-PLP patients eligible for supplementation. limitations: Selected low-PLP RA patients; blood response is not direct all-organ cofactor measurement. exposure: Pyridoxine hydrochloride 50 mg/day or placebo for 30 days; historical trial exposure, not a regimen recommendation. [b6-chiang2005-trial] Pyridoxine supplementation corrects vitamin B6 deficiency but does not improve inflammation in patients with rheumatoid arthritis (2005). https://pubmed.ncbi.nlm.nih.gov/16277693/ DOI: 10.1186/ar1839

experimental_model

Single patient with homocystinuria and long-term high-dose pyridoxine exposure.

exposure

1250–1750 mg/day for 20 years; subsequently reduced to 500 mg/day. Case history, not evidence that the reduced dose is safe generally.

limitations

Single homocystinuria case; does not establish universal reversibility or safety of 500 mg/day. The article background statement about 50 mg is not treated as an experimentally determined threshold.

nutrient_topic

Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6

organism

Homo sapiens

plain_language

Recovery was possible in this individual despite long exposure.

primary_references

[b6-echanizlaguna2018] Regressive pyridoxine-induced sensory neuronopathy in a patient with homocystinuria (2018). https://pubmed.ncbi.nlm.nih.gov/29954767/ DOI: 10.1136/bcr-2018-225059

tissue_or_cell_type

Peripheral sensory nerves

Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1596–1606

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Single patient with homocystinuria and long-term high-dose pyridoxine exposure. · source_derived_draft · unverified_draft

### b6-toxicity-case-recovery After long-term 1250–1750 mg/day exposure, the reported patient recovered sensory function and nerve potentials following reduction to 500 mg/day. Condition category: normal nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Recovery was possible in this individual despite long exposure. organism: Homo sapiens tissue_or_cell_type: Peripheral sensory nerves experimental_model: Single patient with homocystinuria and long-term high-dose pyridoxine exposure. limitations: Single homocystinuria case; does not establish universal reversibility or safety of 500 mg/day. The article background statement about 50 mg is not treated as an experimentally determined threshold. exposure: 1250–1750 mg/day for 20 years; subsequently reduced to 500 mg/day. Case history, not evidence that the reduced dose is safe generally. [b6-echanizlaguna2018] Regressive pyridoxine-induced sensory neuronopathy in a patient with homocystinuria (2018). https://pubmed.ncbi.nlm.nih.gov/29954767/ DOI: 10.1136/bcr-2018-225059

experimental_model

Five healthy volunteers prospectively followed during experimental pyridoxine excess.

exposure

Pyridoxine 1 or 3 g/day, stopped with clinical/laboratory abnormality; very high historical exposures.

limitations

Demonstrates clinical timing; does not identify the molecular injury mechanism or prove irreversible damage.

nutrient_topic

Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6

organism

Homo sapiens

plain_language

A blood vitamin level returned to normal before the nerve symptoms stopped worsening.

primary_references

[b6-berger1992] Dose response, coasting, and differential fiber vulnerability in human toxic neuropathy: a prospective study of pyridoxine neurotoxicity (1992). https://pubmed.ncbi.nlm.nih.gov/1620347/ DOI: 10.1212/wnl.42.7.1367

tissue_or_cell_type

Peripheral sensory function after exposure withdrawal

Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1584–1594

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Five healthy volunteers prospectively followed during experimental pyridoxine excess. · source_derived_draft · unverified_draft

### b6-toxicity-coasting Symptoms progressed for two to three weeks after pyridoxine withdrawal despite normalized serum PLP. Condition category: normal nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: A blood vitamin level returned to normal before the nerve symptoms stopped worsening. organism: Homo sapiens tissue_or_cell_type: Peripheral sensory function after exposure withdrawal experimental_model: Five healthy volunteers prospectively followed during experimental pyridoxine excess. limitations: Demonstrates clinical timing; does not identify the molecular injury mechanism or prove irreversible damage. exposure: Pyridoxine 1 or 3 g/day, stopped with clinical/laboratory abnormality; very high historical exposures. [b6-berger1992] Dose response, coasting, and differential fiber vulnerability in human toxic neuropathy: a prospective study of pyridoxine neurotoxicity (1992). https://pubmed.ncbi.nlm.nih.gov/1620347/ DOI: 10.1212/wnl.42.7.1367

experimental_model

Five healthy volunteers prospectively followed during experimental pyridoxine excess.

exposure

Pyridoxine 1 or 3 g/day, stopped with clinical/laboratory abnormality; very high historical exposures.

limitations

Small experimental groups; not a diagnostic screening protocol.

nutrient_topic

Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6

organism

Homo sapiens

plain_language

Different nerve tests detected the developing injury at different times.

primary_references

[b6-berger1992] Dose response, coasting, and differential fiber vulnerability in human toxic neuropathy: a prospective study of pyridoxine neurotoxicity (1992). https://pubmed.ncbi.nlm.nih.gov/1620347/ DOI: 10.1212/wnl.42.7.1367

tissue_or_cell_type

Peripheral sensory nerve function

Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1572–1582

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Five healthy volunteers prospectively followed during experimental pyridoxine excess. · source_derived_draft · unverified_draft

### b6-toxicity-early-sensory-tests Thermal thresholds changed before or more strongly than vibration thresholds in the lower-dose group; sensory nerve-potential changes lagged thresholds in two of three subjects. Condition category: normal nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Different nerve tests detected the developing injury at different times. organism: Homo sapiens tissue_or_cell_type: Peripheral sensory nerve function experimental_model: Five healthy volunteers prospectively followed during experimental pyridoxine excess. limitations: Small experimental groups; not a diagnostic screening protocol. exposure: Pyridoxine 1 or 3 g/day, stopped with clinical/laboratory abnormality; very high historical exposures. [b6-berger1992] Dose response, coasting, and differential fiber vulnerability in human toxic neuropathy: a prospective study of pyridoxine neurotoxicity (1992). https://pubmed.ncbi.nlm.nih.gov/1620347/ DOI: 10.1212/wnl.42.7.1367

evidence_location

Indexed abstract: pH-dependent saturation and sodium independence

experimental_model

Human Caco-2 intestinal epithelial cells.

exposure

Radiotracer uptake at controlled extracellular pH.

limitations

Carrier identity was not established; uptake behavior alone does not identify a transporter gene.

nutrient_topic

Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6

organism

Homo sapiens

plain_language

Acidic conditions exposed a saturable uptake component.

primary_references

[said2003] A carrier-mediated mechanism for pyridoxine uptake by human intestinal epithelial Caco-2 cells: regulation by a PKA-mediated pathway. (2003). https://pubmed.ncbi.nlm.nih.gov/12867360/ DOI: 10.1152/ajpcell.00204.2003

tissue_or_cell_type

Caco-2 cells

Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 111–122

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human Caco-2 intestinal epithelial cells. · source_derived_draft · unverified_draft

### b6-transport-caco2-pn-uptake Caco-2 pyridoxine uptake was energy-dependent and sodium-independent; saturation occurred at pH 5.5 (apparent Km 11.99 micromolar), but not pH 7.4. Condition category: normal nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Acidic conditions exposed a saturable uptake component. organism: Homo sapiens tissue_or_cell_type: Caco-2 cells experimental_model: Human Caco-2 intestinal epithelial cells. limitations: Carrier identity was not established; uptake behavior alone does not identify a transporter gene. exposure: Radiotracer uptake at controlled extracellular pH. evidence_location: Indexed abstract: pH-dependent saturation and sodium independence [said2003] A carrier-mediated mechanism for pyridoxine uptake by human intestinal epithelial Caco-2 cells: regulation by a PKA-mediated pathway. (2003). https://pubmed.ncbi.nlm.nih.gov/12867360/ DOI: 10.1152/ajpcell.00204.2003

evidence_location

Results: Incubation with pyridoxine; Figure 4

experimental_model

Polarized human Caco-2 monolayers; human intestinal lysates.

exposure

100 or 1000 nM PN; 6-48 h.

limitations

Vitamer measurements establish net conversion; individual enzyme fluxes were not separately perturbed.

nutrient_topic

Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6

organism

Homo sapiens

plain_language

Enterocytes can process a precursor before releasing pyridoxal.

primary_references

[albersen2013] The intestine plays a substantial role in human vitamin B6 metabolism: a Caco-2 cell model. (2013). https://pubmed.ncbi.nlm.nih.gov/23342087/ DOI: 10.1371/journal.pone.0054113

tissue_or_cell_type

Polarized Caco-2 monolayers

Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 124–135

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Polarized human Caco-2 monolayers; human intestinal lysates. · source_derived_draft · unverified_draft

### b6-transport-enterocyte-pn-to-pl Polarized Caco-2 cells supplied apically with PN generated PL and released more PL basolaterally than apically. Condition category: normal nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Enterocytes can process a precursor before releasing pyridoxal. organism: Homo sapiens tissue_or_cell_type: Polarized Caco-2 monolayers experimental_model: Polarized human Caco-2 monolayers; human intestinal lysates. limitations: Vitamer measurements establish net conversion; individual enzyme fluxes were not separately perturbed. exposure: 100 or 1000 nM PN; 6-48 h. evidence_location: Results: Incubation with pyridoxine; Figure 4 [albersen2013] The intestine plays a substantial role in human vitamin B6 metabolism: a Caco-2 cell model. (2013). https://pubmed.ncbi.nlm.nih.gov/23342087/ DOI: 10.1371/journal.pone.0054113

evidence_span

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experimental_model

Placebo-controlled evening pyridoxine experiment

exposure

100 mg pyridoxine at 17:00; evening/night sampling

limitations

Acute exposure in healthy men. Null supplementation response does not negate the enzymatic requirement for PLP or settle effects in B6 deficiency.

nutrient_topic

Melatonin research collection; topical membership is not evidence of a direct dietary effect. · Melatonin

organism

Twelve healthy men

plain_language

An enzyme needs B6, but giving extra B6 did not increase the hormone in this experiment.

primary_references

[melatonin-p12080281] The effect of pyridoxine administration on melatonin secretion in normal men. (2002). https://pubmed.ncbi.nlm.nih.gov/12080281/

tissue_or_cell_type

Melatonin secretion, temperature and polysomnography

Melatonin: synthesis, receptors, circadian timing and nutrient interactions (2026-09-17) · lines 773–784

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Placebo-controlled evening pyridoxine experiment · source_derived_draft · unverified_draft

### melatonin-b6-secretion-null Evening pyridoxine did not significantly change melatonin onset, peak, mean or AUC relative to placebo. Condition category: normal nutrient_topic: Melatonin research collection; topical membership is not evidence of a direct dietary effect. plain_language: An enzyme needs B6, but giving extra B6 did not increase the hormone in this experiment. organism: Twelve healthy men tissue_or_cell_type: Melatonin secretion, temperature and polysomnography experimental_model: Placebo-controlled evening pyridoxine experiment limitations: Acute exposure in healthy men. Null supplementation response does not negate the enzymatic requirement for PLP or settle effects in B6 deficiency. exposure: 100 mg pyridoxine at 17:00; evening/night sampling evidence_span: {"source_cache": "artifacts/melatonin-research/12080281.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "04727c17cd3152a4749ec25ff15b36b827efb885501ce058d436fbbea1e9e7a9", "start_char": 0, "end_char": 1222, "text_sha256": "04727c17cd3152a4749ec25ff15b36b827efb885501ce058d436fbbea1e9e7a9"} [melatonin-p12080281] The effect of pyridoxine administration on melatonin secretion in normal men. (2002). https://pubmed.ncbi.nlm.nih.gov/12080281/

evidence_span

{"source_cache": "artifacts/melatonin-research/12080281.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "04727c17cd3152a4749ec25ff15b36b827efb885501ce058d436fbbea1e9e7a9", "start_char": 0, "end_char": 1222, "text_sha256": "04727c17cd3152a4749ec25ff15b36b827efb885501ce058d436fbbea1e9e7a9"}

experimental_model

Placebo-controlled evening pyridoxine experiment

exposure

100 mg pyridoxine at 17:00; evening/night sampling

limitations

Acute exposure in healthy men. Null supplementation response does not negate the enzymatic requirement for PLP or settle effects in B6 deficiency.

nutrient_topic

Melatonin research collection; topical membership is not evidence of a direct dietary effect. · Melatonin

organism

Twelve healthy men

plain_language

A plausible precursor pathway did not guarantee an observable sleep improvement.

primary_references

[melatonin-p12080281] The effect of pyridoxine administration on melatonin secretion in normal men. (2002). https://pubmed.ncbi.nlm.nih.gov/12080281/

tissue_or_cell_type

Melatonin secretion, temperature and polysomnography

Melatonin: synthesis, receptors, circadian timing and nutrient interactions (2026-09-17) · lines 786–797

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Placebo-controlled evening pyridoxine experiment · source_derived_draft · unverified_draft

### melatonin-b6-sleep-null Sleep amount and architecture were similar after pyridoxine and placebo. Condition category: normal nutrient_topic: Melatonin research collection; topical membership is not evidence of a direct dietary effect. plain_language: A plausible precursor pathway did not guarantee an observable sleep improvement. organism: Twelve healthy men tissue_or_cell_type: Melatonin secretion, temperature and polysomnography experimental_model: Placebo-controlled evening pyridoxine experiment limitations: Acute exposure in healthy men. Null supplementation response does not negate the enzymatic requirement for PLP or settle effects in B6 deficiency. exposure: 100 mg pyridoxine at 17:00; evening/night sampling evidence_span: {"source_cache": "artifacts/melatonin-research/12080281.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "04727c17cd3152a4749ec25ff15b36b827efb885501ce058d436fbbea1e9e7a9", "start_char": 0, "end_char": 1222, "text_sha256": "04727c17cd3152a4749ec25ff15b36b827efb885501ce058d436fbbea1e9e7a9"} [melatonin-p12080281] The effect of pyridoxine administration on melatonin secretion in normal men. (2002). https://pubmed.ncbi.nlm.nih.gov/12080281/

evidence_location

Indexed abstract and publisher abstract; human enzyme findings only

experimental_model

Purified recombinant human and E. coli pyridoxal kinases.

exposure

Purified-enzyme substrate kinetics.

limitations

Model-specific evidence; no dietary threshold or treatment benefit established.

nutrient_topic

Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6

organism

Homo sapiens

plain_language

PDXK adds phosphate to this B6 precursor.

primary_references

[disalvo2004] Expression, purification, and kinetic constants for human and Escherichia coli pyridoxal kinases. (2004). https://pubmed.ncbi.nlm.nih.gov/15249053/ DOI: 10.1016/j.pep.2004.04.021

tissue_or_cell_type

Purified human enzyme

Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 163–174

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified recombinant human and E. coli pyridoxal kinases. · source_derived_draft · unverified_draft

### b6-transport-pdxk-pn Purified recombinant human PDXK phosphorylated pyridoxine to its corresponding 5-prime phosphate. Condition category: normal nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: PDXK adds phosphate to this B6 precursor. organism: Homo sapiens tissue_or_cell_type: Purified human enzyme experimental_model: Purified recombinant human and E. coli pyridoxal kinases. limitations: Model-specific evidence; no dietary threshold or treatment benefit established. exposure: Purified-enzyme substrate kinetics. evidence_location: Indexed abstract and publisher abstract; human enzyme findings only [disalvo2004] Expression, purification, and kinetic constants for human and Escherichia coli pyridoxal kinases. (2004). https://pubmed.ncbi.nlm.nih.gov/15249053/ DOI: 10.1016/j.pep.2004.04.021

evidence_location

Indexed abstract: cloning and substrate hydrolysis

experimental_model

Recombinant human pyridoxal phosphatase expressed in E. coli.

exposure

Recombinant-enzyme characterization.

limitations

Model-specific evidence; no dietary threshold or treatment benefit established.

nutrient_topic

Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6

organism

Homo sapiens

plain_language

PDXP removes phosphate from a B6 vitamer.

primary_references

[jang2003] Human pyridoxal phosphatase. Molecular cloning, functional expression, and tissue distribution. (2003). https://pubmed.ncbi.nlm.nih.gov/14522954/ DOI: 10.1074/jbc.m309619200

tissue_or_cell_type

Purified recombinant human enzyme

Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 269–280

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Recombinant human pyridoxal phosphatase expressed in E. coli. · source_derived_draft · unverified_draft

### b6-transport-pdxp-pnp Catalytically active recombinant human pyridoxal phosphatase hydrolyzed pyridoxine-phosphate. Condition category: normal nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: PDXP removes phosphate from a B6 vitamer. organism: Homo sapiens tissue_or_cell_type: Purified recombinant human enzyme experimental_model: Recombinant human pyridoxal phosphatase expressed in E. coli. limitations: Model-specific evidence; no dietary threshold or treatment benefit established. exposure: Recombinant-enzyme characterization. evidence_location: Indexed abstract: cloning and substrate hydrolysis [jang2003] Human pyridoxal phosphatase. Molecular cloning, functional expression, and tissue distribution. (2003). https://pubmed.ncbi.nlm.nih.gov/14522954/ DOI: 10.1074/jbc.m309619200

availability_state

machinery_impairment Imported condition classification; unverified.

evidence_location

Figure 4A-B

experimental_model

Human K562 knockout cells, Mito-IP, LC-MS and isotope tracing.

exposure

100 nM D3-PN, one-hour tracing after 10 nM PN conditioning.

limitations

Import, retention and indirect regulation remain alternatives.

nutrient_topic

Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6

organism

Homo sapiens

plain_language

Synthesis persisted while mitochondrial accumulation failed.

primary_references

[pena2025] SLC25A38 is required for mitochondrial pyridoxal 5'-phosphate (PLP) accumulation. (2025). https://pubmed.ncbi.nlm.nih.gov/39856062/ DOI: 10.1038/s41467-025-56130-3

tissue_or_cell_type

K562 cells

trigger_kind

machinery_impairment Imported condition classification; unverified.

Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 465–476

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human K562 knockout cells, Mito-IP, LC-MS and isotope tracing. · source_derived_draft · unverified_draft

### b6-transport-slc25a38-tracer After a 100 nM D3-PN pulse, labeled PLP appeared in whole cells but scarcely in SLC25A38-null mitochondria. Condition category: machinery_impairment nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Synthesis persisted while mitochondrial accumulation failed. organism: Homo sapiens tissue_or_cell_type: K562 cells experimental_model: Human K562 knockout cells, Mito-IP, LC-MS and isotope tracing. limitations: Import, retention and indirect regulation remain alternatives. exposure: 100 nM D3-PN, one-hour tracing after 10 nM PN conditioning. evidence_location: Figure 4A-B [pena2025] SLC25A38 is required for mitochondrial pyridoxal 5'-phosphate (PLP) accumulation. (2025). https://pubmed.ncbi.nlm.nih.gov/39856062/ DOI: 10.1038/s41467-025-56130-3

cross_nutrient

A pH-dependent shared transport route links B1 and the pyridoxine form of B6.

evidence-scope

Cultured epithelial cells

evidence_locator

Figures 1-3, 6 and 9

evidence_spans

[{"source_document": "artifacts/thiamine_transport_sources/yamashiro-2020-pyridoxine-source-record.json", "source_field": "resultList.result[0].abstractText", "start_char": 0, "end_char": 1718}]

experimental_model

Human transporter constructs in MDCKII/HEK293 cells; radiotracer uptake at pH 5.5.

extracellular-pH

5.5

limitations

No systemic B6 transport fraction or supplementation benefit established.

nutrient_topic

Thiamine research collection; topical membership is not evidence of a direct dietary effect. · Thiamine (vitamin B1)

organism

Human proteins; canine and human cell hosts

plain_language

The B1 carrier can also carry one B6 form under acidic conditions.

primary_references

[yamashiro-2020-pyridoxine] pH-dependent pyridoxine transport by SLC19A2 and SLC19A3: Implications for absorption in acidic microclimates (2020). https://pmc.ncbi.nlm.nih.gov/articles/PMC7863892/ DOI: 10.1074/jbc.RA120.013610

tissue_or_cell_type

Cultured epithelial cells

Thiamine: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 631–645

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human transporter constructs in MDCKII/HEK293 cells; radiotracer uptake at pH 5.5. · source_derived_draft · unverified_draft

### b1-slc19a3-pyridoxine-transport Human SLC19A3 expression increased pyridoxine uptake at pH 5.5; transport favored acidic over neutral/basic conditions. Condition category: normal nutrient_topic: Thiamine research collection; topical membership is not evidence of a direct dietary effect. plain_language: The B1 carrier can also carry one B6 form under acidic conditions. organism: Human proteins; canine and human cell hosts tissue_or_cell_type: Cultured epithelial cells experimental_model: Human transporter constructs in MDCKII/HEK293 cells; radiotracer uptake at pH 5.5. limitations: No systemic B6 transport fraction or supplementation benefit established. cross_nutrient: A pH-dependent shared transport route links B1 and the pyridoxine form of B6. evidence_spans: [{"source_document": "artifacts/thiamine_transport_sources/yamashiro-2020-pyridoxine-source-record.json", "source_field": "resultList.result[0].abstractText", "start_char": 0, "end_char": 1718}] evidence_locator: Figures 1-3, 6 and 9 extracellular-pH: 5.5 evidence-scope: Cultured epithelial cells [yamashiro-2020-pyridoxine] pH-dependent pyridoxine transport by SLC19A2 and SLC19A3: Implications for absorption in acidic microclimates (2020). https://pmc.ncbi.nlm.nih.gov/articles/PMC7863892/ DOI: 10.1074/jbc.RA120.013610

cross_nutrient

Direct B1-to-pyridoxine transport inhibition is demonstrated in vitro, with pH and exposure limitations.

evidence-scope

Cultured epithelial cells

evidence_locator

Figures 1-3, 6 and 9

evidence_spans

[{"source_document": "artifacts/thiamine_transport_sources/yamashiro-2020-pyridoxine-source-record.json", "source_field": "resultList.result[0].abstractText", "start_char": 0, "end_char": 1718}]

experimental_model

Human transporter constructs in MDCKII/HEK293 cells; radiotracer uptake at pH 5.5.

extracellular-pH

5.5

limitations

Assay inhibition does not show clinical B6 deficiency from dietary thiamine.

nutrient_topic

Thiamine research collection; topical membership is not evidence of a direct dietary effect. · Thiamine (vitamin B1)

organism

Human proteins; canine and human cell hosts

plain_language

B1 reduced uptake of a B6 form in these transporter experiments.

primary_references

[yamashiro-2020-pyridoxine] pH-dependent pyridoxine transport by SLC19A2 and SLC19A3: Implications for absorption in acidic microclimates (2020). https://pmc.ncbi.nlm.nih.gov/articles/PMC7863892/ DOI: 10.1074/jbc.RA120.013610

tissue_or_cell_type

Cultured epithelial cells

Thiamine: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 647–661

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human transporter constructs in MDCKII/HEK293 cells; radiotracer uptake at pH 5.5. · source_derived_draft · unverified_draft

### b1-thiamine-inhibits-pyridoxine-uptake Thiamine inhibited SLC19A2- and SLC19A3-mediated pyridoxine uptake in acidic-pH transfectant assays. Condition category: normal nutrient_topic: Thiamine research collection; topical membership is not evidence of a direct dietary effect. plain_language: B1 reduced uptake of a B6 form in these transporter experiments. organism: Human proteins; canine and human cell hosts tissue_or_cell_type: Cultured epithelial cells experimental_model: Human transporter constructs in MDCKII/HEK293 cells; radiotracer uptake at pH 5.5. limitations: Assay inhibition does not show clinical B6 deficiency from dietary thiamine. cross_nutrient: Direct B1-to-pyridoxine transport inhibition is demonstrated in vitro, with pH and exposure limitations. evidence_spans: [{"source_document": "artifacts/thiamine_transport_sources/yamashiro-2020-pyridoxine-source-record.json", "source_field": "resultList.result[0].abstractText", "start_char": 0, "end_char": 1718}] evidence_locator: Figures 1-3, 6 and 9 extracellular-pH: 5.5 evidence-scope: Cultured epithelial cells [yamashiro-2020-pyridoxine] pH-dependent pyridoxine transport by SLC19A2 and SLC19A3: Implications for absorption in acidic microclimates (2020). https://pmc.ncbi.nlm.nih.gov/articles/PMC7863892/ DOI: 10.1074/jbc.RA120.013610

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

Riboflavin (vitamin B2) (supplied_co_nutrient); Pyridoxine (supplied_co_nutrient)

evidence_span

{"source_cache": "artifacts/niacin-clinical-sources/goldsmith1952.txt", "locator": "Primary full report; exact character range, zero-based and end-exclusive", "file_sha256": "2d4004fb5985f80c8e44909506e1aa05b6eefd838f4c28102beac30fb3092bc5", "start_char": 15452, "end_char": 16019, "text_sha256": "66c68d7739e59c3e98f30fe0757f468a7952746f7dfe082138dfa6727fa54bf4"}

experimental_model

Historical metabolic-ward restriction; seven women, with three prolonged corn-diet cases developing pellagra

exposure

Corn diet about 4.7 mg niacin and 190 mg tryptophan/day; other B-vitamin supplements; 40–135 days depending on subject; subsequent niacinamide or DL-tryptophan

limitations

Very small nonrandomized historical experiment. Diets and exposure durations differed; signs were not universal. Nitrogen balance did not prove niacin sufficiency. This does not establish a modern intake threshold or demonstrate a corn toxin.

nutrient_topic

Niacin research collection; topical membership is not evidence of a direct dietary effect. · Niacin (vitamin B3)

organism

Homo sapiens

plain_language

A sore mouth can arise from different nutrient problems. The appearance alone did not identify which vitamin was lacking.

primary_references

[nia-clin-goldsmith1952] Studies of niacin requirement in man. I. Experimental pellagra in subjects on corn diets low in niacin and tryptophan. (1952). https://pubmed.ncbi.nlm.nih.gov/14938430/ DOI: 10.1172/jci102638

supplementary_evidence_spans

[{"source_cache": "artifacts/niacin-clinical-sources/goldsmith1952.txt", "start_char": 8901, "end_char": 9290, "file_sha256": "2d4004fb5985f80c8e44909506e1aa05b6eefd838f4c28102beac30fb3092bc5", "text_sha256": "59d1a659822aca95688b5e36bd07b41ea700bfbfdc92b40005acf11bd540b046", "locator": "Methods: supplied B-vitamin quantities"}, {"source_cache": "artifacts/niacin-clinical-sources/goldsmith1952.txt", "start_char": 31540, "end_char": 31811, "file_sha256": "2d4004fb5985f80c8e44909506e1aa05b6eefd838f4c28102beac30fb3092bc5", "text_sha256": "ff226f4114a9dec08a00118aa9df933b8246dc89bcf362b2569c089b511d9d3e", "locator": "Discussion: riboflavin and pyridoxine supplements"}]

tissue_or_cell_type

Skin, oral and intestinal mucosa

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Niacin: NAD metabolism, deficiency and nutrient interactions (2026-09-17) · lines 1205–1218

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Historical metabolic-ward restriction; seven women, with three prolonged corn-diet cases developing pellagra · source_derived_draft · unverified_draft

### nia-clin-pellagra-riboflavin-context Cheilosis and angular stomatitis occurred during the low-niacin/tryptophan regimen even with approximately 2 mg/day total riboflavin and supplemental pyridoxine; these lesions were not specific evidence of B2 deficiency. Condition category: nutrient_deficiency nutrient_topic: Niacin research collection; topical membership is not evidence of a direct dietary effect. plain_language: A sore mouth can arise from different nutrient problems. The appearance alone did not identify which vitamin was lacking. organism: Homo sapiens tissue_or_cell_type: Skin, oral and intestinal mucosa experimental_model: Historical metabolic-ward restriction; seven women, with three prolonged corn-diet cases developing pellagra limitations: Very small nonrandomized historical experiment. Diets and exposure durations differed; signs were not universal. Nitrogen balance did not prove niacin sufficiency. This does not establish a modern intake threshold or demonstrate a corn toxin. exposure: Corn diet about 4.7 mg niacin and 190 mg tryptophan/day; other B-vitamin supplements; 40–135 days depending on subject; subsequent niacinamide or DL-tryptophan cross_nutrient: Riboflavin (vitamin B2) (supplied_co_nutrient); Pyridoxine (supplied_co_nutrient) evidence_span: {"source_cache": "artifacts/niacin-clinical-sources/goldsmith1952.txt", "locator": "Primary full report; exact character range, zero-based and end-exclusive", "file_sha256": "2d4004fb5985f80c8e44909506e1aa05b6eefd838f4c28102beac30fb3092bc5", "start_char": 15452, "end_char": 16019, "text_sha256": "66c68d7739e59c3e98f30fe0757f468a7952746f7dfe082138dfa6727fa54bf4"} supplementary_evidence_spans: [{"source_cache": "artifacts/niacin-clinical-sources/goldsmith1952.txt", "start_char": 8901, "end_char": 9290, "file_sha256": "2d4004fb5985f80c8e44909506e1aa05b6eefd838f4c28102beac30fb3092bc5", "text_sha256": "59d1a659822aca95688b5e36bd07b41ea700bfbfdc92b40005acf11bd540b046", "locator": "Methods: supplied B-vitamin quantities"}, {"source_cache": "artifacts/niacin-clinical-sources/goldsmith1952.txt", "start_char": 31540, "end_char": 31811, "file_sha256": "2d4004fb5985f80c8e44909506e1aa05b6eefd838f4c28102beac30fb3092bc5", "text_sha256": "ff226f4114a9dec08a00118aa9df933b8246dc89bcf362b2569c089b511d9d3e", "locator": "Discussion: riboflavin and pyridoxine supplements"}] [nia-clin-goldsmith1952] Studies of niacin requirement in man. I. Experimental pellagra in subjects on corn diets low in niacin and tryptophan. (1952). https://pubmed.ncbi.nlm.nih.gov/14938430/ DOI: 10.1172/jci102638

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

true

evidence_location

Publisher primary Summary at https://www.sciencedirect.com/science/article/abs/pii/S0002916523345945 ; full article not retrieved.

experimental_model

Historical two-stage combined B5/B6 depletion experiment in male volunteers

exposure

First stage: two controls, two diet-only deficient men and one receiving diet plus both antagonists. Second stage: five men received B5/B6-deficient diet plus omega-methyl pantothenic acid and desoxypyridoxine; exact doses not available in the publisher summary.

limitations

Combined nutrient restriction plus antivitamins cannot identify the separate contribution of B5 or B6, a synergistic effect, or a universal immune defect. Reimmunization also changes prior antigen exposure.

nutrient_topic

Pantothenic acid (vitamin B5) research collection; topical membership is not evidence of a direct dietary effect. · Pantothenate (vitamin B5)

organism

Homo sapiens

plain_language

Combined depletion and antivitamins impaired some antibody responses.

primary_references

[b5-clin-hodges1962] Factors affecting human antibody response. V. Combined deficiencies of pantothenic acid and pyridoxine. (1962). https://pubmed.ncbi.nlm.nih.gov/13907960/ DOI: 10.1093/ajcn/11.3.187

tissue_or_cell_type

Immunization responses and serum proteins

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Pantothenic acid (vitamin B5): coenzyme A, deficiency and nutrient interactions (2026-09-17) · lines 1327–1339

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Historical two-stage combined B5/B6 depletion experiment in male volunteers · source_derived_draft · unverified_draft

### b5-clin-combined-antibody-loss The five men receiving B5/B6-deficient diet plus both antagonists failed to respond to tetanus and typhoid O immunization and had little typhoid H response. Condition category: nutrient_deficiency nutrient_topic: Pantothenic acid (vitamin B5) research collection; topical membership is not evidence of a direct dietary effect. plain_language: Combined depletion and antivitamins impaired some antibody responses. organism: Homo sapiens tissue_or_cell_type: Immunization responses and serum proteins experimental_model: Historical two-stage combined B5/B6 depletion experiment in male volunteers limitations: Combined nutrient restriction plus antivitamins cannot identify the separate contribution of B5 or B6, a synergistic effect, or a universal immune defect. Reimmunization also changes prior antigen exposure. exposure: First stage: two controls, two diet-only deficient men and one receiving diet plus both antagonists. Second stage: five men received B5/B6-deficient diet plus omega-methyl pantothenic acid and desoxypyridoxine; exact doses not available in the publisher summary. cross_nutrient: true evidence_location: Publisher primary Summary at https://www.sciencedirect.com/science/article/abs/pii/S0002916523345945 ; full article not retrieved. [b5-clin-hodges1962] Factors affecting human antibody response. V. Combined deficiencies of pantothenic acid and pyridoxine. (1962). https://pubmed.ncbi.nlm.nih.gov/13907960/ DOI: 10.1093/ajcn/11.3.187

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

true

evidence_location

Publisher primary Summary at https://www.sciencedirect.com/science/article/abs/pii/S0002916523345945 ; full article not retrieved.

experimental_model

Historical two-stage combined B5/B6 depletion experiment in male volunteers

exposure

First stage: two controls, two diet-only deficient men and one receiving diet plus both antagonists. Second stage: five men received B5/B6-deficient diet plus omega-methyl pantothenic acid and desoxypyridoxine; exact doses not available in the publisher summary.

limitations

Combined nutrient restriction plus antivitamins cannot identify the separate contribution of B5 or B6, a synergistic effect, or a universal immune defect. Reimmunization also changes prior antigen exposure. This is not a blinded comparison of B5 alone, B6 alone or their interaction.

nutrient_topic

Pantothenic acid (vitamin B5) research collection; topical membership is not evidence of a direct dietary effect. · Pantothenate (vitamin B5)

organism

Homo sapiens

plain_language

Responses recovered after combined vitamin restoration and another immunization.

primary_references

[b5-clin-hodges1962] Factors affecting human antibody response. V. Combined deficiencies of pantothenic acid and pyridoxine. (1962). https://pubmed.ncbi.nlm.nih.gov/13907960/ DOI: 10.1093/ajcn/11.3.187

tissue_or_cell_type

Immunization responses and serum proteins

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Pantothenic acid (vitamin B5): coenzyme A, deficiency and nutrient interactions (2026-09-17) · lines 1355–1367

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Historical two-stage combined B5/B6 depletion experiment in male volunteers · source_derived_draft · unverified_draft

### b5-clin-combined-immune-recovery After vitamins were restored and the five subjects were reimmunized, tetanus and typhoid antibody responses were reported as normal. Condition category: nutrient_deficiency nutrient_topic: Pantothenic acid (vitamin B5) research collection; topical membership is not evidence of a direct dietary effect. plain_language: Responses recovered after combined vitamin restoration and another immunization. organism: Homo sapiens tissue_or_cell_type: Immunization responses and serum proteins experimental_model: Historical two-stage combined B5/B6 depletion experiment in male volunteers limitations: Combined nutrient restriction plus antivitamins cannot identify the separate contribution of B5 or B6, a synergistic effect, or a universal immune defect. Reimmunization also changes prior antigen exposure. This is not a blinded comparison of B5 alone, B6 alone or their interaction. exposure: First stage: two controls, two diet-only deficient men and one receiving diet plus both antagonists. Second stage: five men received B5/B6-deficient diet plus omega-methyl pantothenic acid and desoxypyridoxine; exact doses not available in the publisher summary. cross_nutrient: true evidence_location: Publisher primary Summary at https://www.sciencedirect.com/science/article/abs/pii/S0002916523345945 ; full article not retrieved. [b5-clin-hodges1962] Factors affecting human antibody response. V. Combined deficiencies of pantothenic acid and pyridoxine. (1962). https://pubmed.ncbi.nlm.nih.gov/13907960/ DOI: 10.1093/ajcn/11.3.187

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

true

evidence_location

Publisher primary Summary at https://www.sciencedirect.com/science/article/abs/pii/S0002916523345945 ; full article not retrieved.

experimental_model

Historical two-stage combined B5/B6 depletion experiment in male volunteers

exposure

First stage: two controls, two diet-only deficient men and one receiving diet plus both antagonists. Second stage: five men received B5/B6-deficient diet plus omega-methyl pantothenic acid and desoxypyridoxine; exact doses not available in the publisher summary.

limitations

Combined nutrient restriction plus antivitamins cannot identify the separate contribution of B5 or B6, a synergistic effect, or a universal immune defect. Reimmunization also changes prior antigen exposure.

nutrient_topic

Pantothenic acid (vitamin B5) research collection; topical membership is not evidence of a direct dietary effect. · Pantothenate (vitamin B5)

organism

Homo sapiens

plain_language

The immune impairment did not affect every tested antigen equally.

primary_references

[b5-clin-hodges1962] Factors affecting human antibody response. V. Combined deficiencies of pantothenic acid and pyridoxine. (1962). https://pubmed.ncbi.nlm.nih.gov/13907960/ DOI: 10.1093/ajcn/11.3.187

tissue_or_cell_type

Immunization responses and serum proteins

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Pantothenic acid (vitamin B5): coenzyme A, deficiency and nutrient interactions (2026-09-17) · lines 1341–1353

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Historical two-stage combined B5/B6 depletion experiment in male volunteers · source_derived_draft · unverified_draft

### b5-clin-combined-polio-preserved The same five men retained strong antibody responses to polio immunization despite their impaired tetanus and typhoid responses. Condition category: nutrient_deficiency nutrient_topic: Pantothenic acid (vitamin B5) research collection; topical membership is not evidence of a direct dietary effect. plain_language: The immune impairment did not affect every tested antigen equally. organism: Homo sapiens tissue_or_cell_type: Immunization responses and serum proteins experimental_model: Historical two-stage combined B5/B6 depletion experiment in male volunteers limitations: Combined nutrient restriction plus antivitamins cannot identify the separate contribution of B5 or B6, a synergistic effect, or a universal immune defect. Reimmunization also changes prior antigen exposure. exposure: First stage: two controls, two diet-only deficient men and one receiving diet plus both antagonists. Second stage: five men received B5/B6-deficient diet plus omega-methyl pantothenic acid and desoxypyridoxine; exact doses not available in the publisher summary. cross_nutrient: true evidence_location: Publisher primary Summary at https://www.sciencedirect.com/science/article/abs/pii/S0002916523345945 ; full article not retrieved. [b5-clin-hodges1962] Factors affecting human antibody response. V. Combined deficiencies of pantothenic acid and pyridoxine. (1962). https://pubmed.ncbi.nlm.nih.gov/13907960/ DOI: 10.1093/ajcn/11.3.187

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

true

evidence_location

Publisher primary Summary at https://www.sciencedirect.com/science/article/abs/pii/S0002916523345945 ; full article not retrieved.

experimental_model

Historical two-stage combined B5/B6 depletion experiment in male volunteers

exposure

First stage: two controls, two diet-only deficient men and one receiving diet plus both antagonists. Second stage: five men received B5/B6-deficient diet plus omega-methyl pantothenic acid and desoxypyridoxine; exact doses not available in the publisher summary.

limitations

Combined nutrient restriction plus antivitamins cannot identify the separate contribution of B5 or B6, a synergistic effect, or a universal immune defect. Reimmunization also changes prior antigen exposure. Only two subjects; not proof that prolonged isolated dietary deficiency cannot impair immunity.

nutrient_topic

Pantothenic acid (vitamin B5) research collection; topical membership is not evidence of a direct dietary effect. · Pantothenate (vitamin B5)

organism

Homo sapiens

plain_language

Diet-only restriction gave a different result from the later antivitamin regimen.

primary_references

[b5-clin-hodges1962] Factors affecting human antibody response. V. Combined deficiencies of pantothenic acid and pyridoxine. (1962). https://pubmed.ncbi.nlm.nih.gov/13907960/ DOI: 10.1093/ajcn/11.3.187

tissue_or_cell_type

Immunization responses and serum proteins

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Pantothenic acid (vitamin B5): coenzyme A, deficiency and nutrient interactions (2026-09-17) · lines 1369–1381

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Historical two-stage combined B5/B6 depletion experiment in male volunteers · source_derived_draft · unverified_draft

### b5-clin-diet-only-immune-result The two men receiving the B5/B6-deficient diet without antagonists in the first stage showed minor abnormalities but no impairment of antibody production in that stage. Condition category: nutrient_deficiency nutrient_topic: Pantothenic acid (vitamin B5) research collection; topical membership is not evidence of a direct dietary effect. plain_language: Diet-only restriction gave a different result from the later antivitamin regimen. organism: Homo sapiens tissue_or_cell_type: Immunization responses and serum proteins experimental_model: Historical two-stage combined B5/B6 depletion experiment in male volunteers limitations: Combined nutrient restriction plus antivitamins cannot identify the separate contribution of B5 or B6, a synergistic effect, or a universal immune defect. Reimmunization also changes prior antigen exposure. Only two subjects; not proof that prolonged isolated dietary deficiency cannot impair immunity. exposure: First stage: two controls, two diet-only deficient men and one receiving diet plus both antagonists. Second stage: five men received B5/B6-deficient diet plus omega-methyl pantothenic acid and desoxypyridoxine; exact doses not available in the publisher summary. cross_nutrient: true evidence_location: Publisher primary Summary at https://www.sciencedirect.com/science/article/abs/pii/S0002916523345945 ; full article not retrieved. [b5-clin-hodges1962] Factors affecting human antibody response. V. Combined deficiencies of pantothenic acid and pyridoxine. (1962). https://pubmed.ncbi.nlm.nih.gov/13907960/ DOI: 10.1093/ajcn/11.3.187