Component

Niacin (vitamin B3)

Vitamin B3 nutritional family, including nicotinic acid and nicotinamide. Precursor forms, NAD+/NADH and NADP+/NADPH have separate identities; chemical form and experimental exposure determine each claim.

10 recorded relationships. Experimental role, claim status and evidence remain attached to each record.

Read recorded mechanisms Open recursive mind map

How nutrients influence it

Every nutrient with a recorded effect on this component, credited to the nutrient that acted rather than the chapter that recorded it. Open a nutrient to see the findings and the conditions they were measured under.

How nutrients reach it in more than one step

Chains of two or more recorded steps that end here, grouped by the nutrient they start from. Each step is a separate finding, so a chain is a route a mechanism could take, not proof that it does.

Tracing routes…

What it does

Every recorded relationship this component is part of, grouped by its role. Plain wording comes first; the technical statement follows.

Recorded relationships

What it acts on

  1. Urinary N1-methylnicotinamide rose into the high-normal range in 86% of initially niacin-deficient patients after supplementation in this retrospective series.

    Niacin (vitamin B3) → Urinary N1-methylnicotinamide excretion source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    biomarker_context Imported condition classification; unverified.
    cross_nutrient
    N1-methylnicotinamide (measured_metabolite)
    evidence_span
    {"source_cache": "artifacts/niacin-clinical-sources/bouma2016.abstract.txt", "locator": "Indexed primary abstract", "file_sha256": "1c1db5a8c0880ceda2066e1fcf23020ab293689782b99402d9913ff326917497", "start_char": 0, "end_char": 1869, "text_sha256": "1c1db5a8c0880ceda2066e1fcf23020ab293689782b99402d9913ff326917497"}
    experimental_model
    Retrospective serotonin-producing NET cohort; 42 baseline and 34 paired samples; 133 healthy urine references
    exposure
    Patients selected for low tryptophan and/or pellagra-associated symptoms; prescribed oral niacin mean 144 mg/day
    limitations
    No randomized comparator or direct tracer measurement of tryptophan diversion. Biomarker normalization does not establish symptom cure. Indexed abstract does not unambiguously specify the administered chemical form; retain niacin rather than guessing nicotinamide.
    nutrient_topic
    Niacin research collection; topical membership is not evidence of a direct dietary effect. · Niacin (vitamin B3)
    organism
    Homo sapiens
    plain_language
    Supplementation improved the measured niacin-status marker for most deficient patients in this series.
    primary_references
    [nia-clin-bouma2016] Niacin (Vitamin B3) Supplementation in Patients with Serotonin-Producing Neuroendocrine Tumor. (2016). https://pubmed.ncbi.nlm.nih.gov/26335390/ DOI: 10.1159/000440621
    tissue_or_cell_type
    Plasma and urine
    trigger_kind
    biomarker_context Imported condition classification; unverified.

    Niacin: NAD metabolism, deficiency and nutrient interactions (2026-09-17) · lines 1277–1289

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Retrospective serotonin-producing NET cohort; 42 baseline and 34 paired samples; 133 healthy urine references · source_derived_draft · unverified_draft

    ### nia-clin-net-supplement-marker Urinary N1-methylnicotinamide rose into the high-normal range in 86% of initially niacin-deficient patients after supplementation in this retrospective series. Condition category: biomarker_context nutrient_topic: Niacin research collection; topical membership is not evidence of a direct dietary effect. plain_language: Supplementation improved the measured niacin-status marker for most deficient patients in this series. organism: Homo sapiens tissue_or_cell_type: Plasma and urine experimental_model: Retrospective serotonin-producing NET cohort; 42 baseline and 34 paired samples; 133 healthy urine references limitations: No randomized comparator or direct tracer measurement of tryptophan diversion. Biomarker normalization does not establish symptom cure. Indexed abstract does not unambiguously specify the administered chemical form; retain niacin rather than guessing nicotinamide. exposure: Patients selected for low tryptophan and/or pellagra-associated symptoms; prescribed oral niacin mean 144 mg/day cross_nutrient: N1-methylnicotinamide (measured_metabolite) evidence_span: {"source_cache": "artifacts/niacin-clinical-sources/bouma2016.abstract.txt", "locator": "Indexed primary abstract", "file_sha256": "1c1db5a8c0880ceda2066e1fcf23020ab293689782b99402d9913ff326917497", "start_char": 0, "end_char": 1869, "text_sha256": "1c1db5a8c0880ceda2066e1fcf23020ab293689782b99402d9913ff326917497"} [nia-clin-bouma2016] Niacin (Vitamin B3) Supplementation in Patients with Serotonin-Producing Neuroendocrine Tumor. (2016). https://pubmed.ncbi.nlm.nih.gov/26335390/ DOI: 10.1159/000440621
    Complete structured claim and evidence

  2. The three prolonged corn-diet subjects developed initial pellagra signs between days 50 and 60; lesions differed between individuals, and typical hand dermatitis developed later in two.

    Niacin (vitamin B3) → Pellagra clinical lesions source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    nutrient_deficiency Imported condition classification; unverified.
    cross_nutrient
    L-Tryptophan (co_restricted_precursor)
    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": 13468, "end_char": 15488, "text_sha256": "78476c492b7ccdbe08740a06623f5a4856394c368e22b1bfdcdde2bc345e9a36"}
    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
    Long enough shortage injured skin and mucosal tissues, but people did not develop the same signs in the same order.
    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
    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 1191–1203

    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-lesions The three prolonged corn-diet subjects developed initial pellagra signs between days 50 and 60; lesions differed between individuals, and typical hand dermatitis developed later in two. Condition category: nutrient_deficiency nutrient_topic: Niacin research collection; topical membership is not evidence of a direct dietary effect. plain_language: Long enough shortage injured skin and mucosal tissues, but people did not develop the same signs in the same order. 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: L-Tryptophan (co_restricted_precursor) 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": 13468, "end_char": 15488, "text_sha256": "78476c492b7ccdbe08740a06623f5a4856394c368e22b1bfdcdde2bc345e9a36"} [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
    Complete structured claim and evidence

  3. 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.

    Niacin (vitamin B3) → Niacin-related oral mucosal injury source_derived_draftungraded
    Experimental context and source evidence
    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
    Complete structured claim and evidence

  4. At both low niacin-equivalent intakes, erythrocyte NAD fell by about 70% in the seven-man feeding study and increased during adequate-intake repletion.

    Niacin (vitamin B3) → Erythrocyte NAD content source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    nutrient_deficiency Imported condition classification; unverified.
    cross_nutrient
    L-Tryptophan (alternative_precursor); Nicotinamide adenine dinucleotide, oxidized (measured_coenzyme)
    evidence_span
    {"source_cache": "artifacts/niacin-clinical-sources/fu1989.abstract.txt", "locator": "Indexed primary abstract", "file_sha256": "ca6d94c101aca84f1e41f35898434f44770ca563c5bff986fe52e33f797b0fbc", "start_char": 0, "end_char": 1340, "text_sha256": "ca6d94c101aca84f1e41f35898434f44770ca563c5bff986fe52e33f797b0fbc"}
    experimental_model
    Controlled metabolic-unit feeding; seven men, 80 days
    exposure
    6.1 or 10.1 niacin equivalents/day, followed by adequate/high intakes; repletion with or without 7.8 g/day leucine
    limitations
    Small controlled male metabolic-unit study. Erythrocytes are not every tissue; historical adequate intake is not a current recommendation. Jacob and Fu reports may describe related participants and are not counted as independent trials.
    nutrient_topic
    Niacin research collection; topical membership is not evidence of a direct dietary effect. · Niacin (vitamin B3)
    organism
    Homo sapiens
    plain_language
    With too little niacin and tryptophan, red blood cells lost much of their NAD supply; restoring intake raised it.
    primary_references
    [nia-clin-fu1989] Biochemical markers for assessment of niacin status in young men: levels of erythrocyte niacin coenzymes and plasma tryptophan. (1989). https://pubmed.ncbi.nlm.nih.gov/2621487/ DOI: 10.1093/jn/119.12.1949
    tissue_or_cell_type
    Erythrocytes and plasma
    trigger_kind
    nutrient_deficiency Imported condition classification; unverified.

    Niacin: NAD metabolism, deficiency and nutrient interactions (2026-09-17) · lines 1107–1119

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Controlled metabolic-unit feeding; seven men, 80 days · source_derived_draft · unverified_draft

    ### nia-clin-restriction-nad At both low niacin-equivalent intakes, erythrocyte NAD fell by about 70% in the seven-man feeding study and increased during adequate-intake repletion. Condition category: nutrient_deficiency nutrient_topic: Niacin research collection; topical membership is not evidence of a direct dietary effect. plain_language: With too little niacin and tryptophan, red blood cells lost much of their NAD supply; restoring intake raised it. organism: Homo sapiens tissue_or_cell_type: Erythrocytes and plasma experimental_model: Controlled metabolic-unit feeding; seven men, 80 days limitations: Small controlled male metabolic-unit study. Erythrocytes are not every tissue; historical adequate intake is not a current recommendation. Jacob and Fu reports may describe related participants and are not counted as independent trials. exposure: 6.1 or 10.1 niacin equivalents/day, followed by adequate/high intakes; repletion with or without 7.8 g/day leucine cross_nutrient: L-Tryptophan (alternative_precursor); Nicotinamide adenine dinucleotide, oxidized (measured_coenzyme) evidence_span: {"source_cache": "artifacts/niacin-clinical-sources/fu1989.abstract.txt", "locator": "Indexed primary abstract", "file_sha256": "ca6d94c101aca84f1e41f35898434f44770ca563c5bff986fe52e33f797b0fbc", "start_char": 0, "end_char": 1340, "text_sha256": "ca6d94c101aca84f1e41f35898434f44770ca563c5bff986fe52e33f797b0fbc"} [nia-clin-fu1989] Biochemical markers for assessment of niacin status in young men: levels of erythrocyte niacin coenzymes and plasma tryptophan. (1989). https://pubmed.ncbi.nlm.nih.gov/2621487/ DOI: 10.1093/jn/119.12.1949
    Complete structured claim and evidence

  5. Erythrocyte NADP remained relatively unchanged during the low-NE diets that depleted erythrocyte NAD.

    Niacin (vitamin B3) → Erythrocyte NADP content source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    nutrient_deficiency Imported condition classification; unverified.
    cross_nutrient
    Oxidized nicotinamide adenine dinucleotide phosphate (measured_coenzyme)
    evidence_span
    {"source_cache": "artifacts/niacin-clinical-sources/fu1989.abstract.txt", "locator": "Indexed primary abstract", "file_sha256": "ca6d94c101aca84f1e41f35898434f44770ca563c5bff986fe52e33f797b0fbc", "start_char": 0, "end_char": 1340, "text_sha256": "ca6d94c101aca84f1e41f35898434f44770ca563c5bff986fe52e33f797b0fbc"}
    experimental_model
    Controlled metabolic-unit feeding; seven men, 80 days
    exposure
    6.1 or 10.1 niacin equivalents/day, followed by adequate/high intakes; repletion with or without 7.8 g/day leucine
    limitations
    Small controlled male metabolic-unit study. Erythrocytes are not every tissue; historical adequate intake is not a current recommendation. Jacob and Fu reports may describe related participants and are not counted as independent trials.
    nutrient_topic
    Niacin research collection; topical membership is not evidence of a direct dietary effect. · Niacin (vitamin B3)
    organism
    Homo sapiens
    plain_language
    The two coenzyme pools did not fall together; low niacin did not mean equal loss of NAD and NADP.
    primary_references
    [nia-clin-fu1989] Biochemical markers for assessment of niacin status in young men: levels of erythrocyte niacin coenzymes and plasma tryptophan. (1989). https://pubmed.ncbi.nlm.nih.gov/2621487/ DOI: 10.1093/jn/119.12.1949
    tissue_or_cell_type
    Erythrocytes and plasma
    trigger_kind
    nutrient_deficiency Imported condition classification; unverified.

    Niacin: NAD metabolism, deficiency and nutrient interactions (2026-09-17) · lines 1121–1133

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Controlled metabolic-unit feeding; seven men, 80 days · source_derived_draft · unverified_draft

    ### nia-clin-restriction-nadp Erythrocyte NADP remained relatively unchanged during the low-NE diets that depleted erythrocyte NAD. Condition category: nutrient_deficiency nutrient_topic: Niacin research collection; topical membership is not evidence of a direct dietary effect. plain_language: The two coenzyme pools did not fall together; low niacin did not mean equal loss of NAD and NADP. organism: Homo sapiens tissue_or_cell_type: Erythrocytes and plasma experimental_model: Controlled metabolic-unit feeding; seven men, 80 days limitations: Small controlled male metabolic-unit study. Erythrocytes are not every tissue; historical adequate intake is not a current recommendation. Jacob and Fu reports may describe related participants and are not counted as independent trials. exposure: 6.1 or 10.1 niacin equivalents/day, followed by adequate/high intakes; repletion with or without 7.8 g/day leucine cross_nutrient: Oxidized nicotinamide adenine dinucleotide phosphate (measured_coenzyme) evidence_span: {"source_cache": "artifacts/niacin-clinical-sources/fu1989.abstract.txt", "locator": "Indexed primary abstract", "file_sha256": "ca6d94c101aca84f1e41f35898434f44770ca563c5bff986fe52e33f797b0fbc", "start_char": 0, "end_char": 1340, "text_sha256": "ca6d94c101aca84f1e41f35898434f44770ca563c5bff986fe52e33f797b0fbc"} [nia-clin-fu1989] Biochemical markers for assessment of niacin status in young men: levels of erythrocyte niacin coenzymes and plasma tryptophan. (1989). https://pubmed.ncbi.nlm.nih.gov/2621487/ DOI: 10.1093/jn/119.12.1949
    Complete structured claim and evidence

  6. Urinary 2PY below 1.2 mg/day tracked the lowest intake; the urinary 2PY-to-methyl-nicotinamide ratio performed less well than individual metabolite outputs and missed the 10.1-NE/day restriction.

    Niacin (vitamin B3) → Urinary 2PY excretion source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    nutrient_deficiency Imported condition classification; unverified.
    cross_nutrient
    N1-methyl-2-pyridone-5-carboxamide (2PY) (measured_metabolite)
    evidence_span
    {"source_cache": "artifacts/niacin-clinical-sources/jacob1989.abstract.txt", "locator": "Indexed primary abstract", "file_sha256": "749fc69d8d6cb1ba79a0b17e38e9300611713e3939224ba9ac809cef91c7a64c", "start_char": 0, "end_char": 1463, "text_sha256": "749fc69d8d6cb1ba79a0b17e38e9300611713e3939224ba9ac809cef91c7a64c"}
    experimental_model
    Controlled metabolic-unit feeding of young men for 11 weeks
    exposure
    6.1–32 NE/day; oral nicotinamide test doses
    limitations
    Small controlled male metabolic-unit study. Erythrocytes are not every tissue; historical adequate intake is not a current recommendation. Jacob and Fu reports may describe related participants and are not counted as independent trials. Historical NMN abbreviation means N1-methylnicotinamide, not nicotinamide mononucleotide. Urinary output is not a universal diagnostic cutoff.
    nutrient_topic
    Niacin research collection; topical membership is not evidence of a direct dietary effect. · Niacin (vitamin B3)
    organism
    Homo sapiens
    plain_language
    Individual urine measurements were more informative than assuming their ratio was a better marker.
    primary_references
    [nia-clin-jacob1989] Biochemical markers for assessment of niacin status in young men: urinary and blood levels of niacin metabolites. (1989). https://pubmed.ncbi.nlm.nih.gov/2522982/ DOI: 10.1093/jn/119.4.591
    tissue_or_cell_type
    Urine and plasma
    trigger_kind
    nutrient_deficiency Imported condition classification; unverified.

    Niacin: NAD metabolism, deficiency and nutrient interactions (2026-09-17) · lines 1163–1175

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Controlled metabolic-unit feeding of young men for 11 weeks · source_derived_draft · unverified_draft

    ### nia-clin-urine-2py-restriction Urinary 2PY below 1.2 mg/day tracked the lowest intake; the urinary 2PY-to-methyl-nicotinamide ratio performed less well than individual metabolite outputs and missed the 10.1-NE/day restriction. Condition category: nutrient_deficiency nutrient_topic: Niacin research collection; topical membership is not evidence of a direct dietary effect. plain_language: Individual urine measurements were more informative than assuming their ratio was a better marker. organism: Homo sapiens tissue_or_cell_type: Urine and plasma experimental_model: Controlled metabolic-unit feeding of young men for 11 weeks limitations: Small controlled male metabolic-unit study. Erythrocytes are not every tissue; historical adequate intake is not a current recommendation. Jacob and Fu reports may describe related participants and are not counted as independent trials. Historical NMN abbreviation means N1-methylnicotinamide, not nicotinamide mononucleotide. Urinary output is not a universal diagnostic cutoff. exposure: 6.1–32 NE/day; oral nicotinamide test doses cross_nutrient: N1-methyl-2-pyridone-5-carboxamide (2PY) (measured_metabolite) evidence_span: {"source_cache": "artifacts/niacin-clinical-sources/jacob1989.abstract.txt", "locator": "Indexed primary abstract", "file_sha256": "749fc69d8d6cb1ba79a0b17e38e9300611713e3939224ba9ac809cef91c7a64c", "start_char": 0, "end_char": 1463, "text_sha256": "749fc69d8d6cb1ba79a0b17e38e9300611713e3939224ba9ac809cef91c7a64c"} [nia-clin-jacob1989] Biochemical markers for assessment of niacin status in young men: urinary and blood levels of niacin metabolites. (1989). https://pubmed.ncbi.nlm.nih.gov/2522982/ DOI: 10.1093/jn/119.4.591
    Complete structured claim and evidence

  7. Urinary N1-methylnicotinamide below 1.2 mg/day identified the lowest 6.1-NE/day intake in this experiment and was more responsive than 2PY to the 10.1-NE/day diet.

    Niacin (vitamin B3) → Urinary N1-methylnicotinamide excretion source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    nutrient_deficiency Imported condition classification; unverified.
    cross_nutrient
    N1-methylnicotinamide (measured_metabolite)
    evidence_span
    {"source_cache": "artifacts/niacin-clinical-sources/jacob1989.abstract.txt", "locator": "Indexed primary abstract", "file_sha256": "749fc69d8d6cb1ba79a0b17e38e9300611713e3939224ba9ac809cef91c7a64c", "start_char": 0, "end_char": 1463, "text_sha256": "749fc69d8d6cb1ba79a0b17e38e9300611713e3939224ba9ac809cef91c7a64c"}
    experimental_model
    Controlled metabolic-unit feeding of young men for 11 weeks
    exposure
    6.1–32 NE/day; oral nicotinamide test doses
    limitations
    Small controlled male metabolic-unit study. Erythrocytes are not every tissue; historical adequate intake is not a current recommendation. Jacob and Fu reports may describe related participants and are not counted as independent trials. Historical NMN abbreviation means N1-methylnicotinamide, not nicotinamide mononucleotide. Urinary output is not a universal diagnostic cutoff.
    nutrient_topic
    Niacin research collection; topical membership is not evidence of a direct dietary effect. · Niacin (vitamin B3)
    organism
    Homo sapiens
    plain_language
    Less niacin intake left less methylated niacin waste in urine; the study threshold belongs to this particular experiment.
    primary_references
    [nia-clin-jacob1989] Biochemical markers for assessment of niacin status in young men: urinary and blood levels of niacin metabolites. (1989). https://pubmed.ncbi.nlm.nih.gov/2522982/ DOI: 10.1093/jn/119.4.591
    tissue_or_cell_type
    Urine and plasma
    trigger_kind
    nutrient_deficiency Imported condition classification; unverified.

    Niacin: NAD metabolism, deficiency and nutrient interactions (2026-09-17) · lines 1149–1161

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Controlled metabolic-unit feeding of young men for 11 weeks · source_derived_draft · unverified_draft

    ### nia-clin-urine-mna-restriction Urinary N1-methylnicotinamide below 1.2 mg/day identified the lowest 6.1-NE/day intake in this experiment and was more responsive than 2PY to the 10.1-NE/day diet. Condition category: nutrient_deficiency nutrient_topic: Niacin research collection; topical membership is not evidence of a direct dietary effect. plain_language: Less niacin intake left less methylated niacin waste in urine; the study threshold belongs to this particular experiment. organism: Homo sapiens tissue_or_cell_type: Urine and plasma experimental_model: Controlled metabolic-unit feeding of young men for 11 weeks limitations: Small controlled male metabolic-unit study. Erythrocytes are not every tissue; historical adequate intake is not a current recommendation. Jacob and Fu reports may describe related participants and are not counted as independent trials. Historical NMN abbreviation means N1-methylnicotinamide, not nicotinamide mononucleotide. Urinary output is not a universal diagnostic cutoff. exposure: 6.1–32 NE/day; oral nicotinamide test doses cross_nutrient: N1-methylnicotinamide (measured_metabolite) evidence_span: {"source_cache": "artifacts/niacin-clinical-sources/jacob1989.abstract.txt", "locator": "Indexed primary abstract", "file_sha256": "749fc69d8d6cb1ba79a0b17e38e9300611713e3939224ba9ac809cef91c7a64c", "start_char": 0, "end_char": 1463, "text_sha256": "749fc69d8d6cb1ba79a0b17e38e9300611713e3939224ba9ac809cef91c7a64c"} [nia-clin-jacob1989] Biochemical markers for assessment of niacin status in young men: urinary and blood levels of niacin metabolites. (1989). https://pubmed.ncbi.nlm.nih.gov/2522982/ DOI: 10.1093/jn/119.4.591
    Complete structured claim and evidence

Where it participates (unsigned role)

  1. Liver-specific Pcx deletion depleted hepatic NADPH and worsened oxidative stress.

    Liver-specific Pcx-null mouse genotype → Mouse liver NADPH pool source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    machinery_impairment Imported condition classification; unverified.
    evidence_span
    {"source_cache": "artifacts/biotin-research/31006591.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "0dcedbfac623863bd4ae86ed1bb97cef0ef56bd417bd0d49507ef47d16af7b4e", "start_char": 0, "end_char": 1141, "text_sha256": "0dcedbfac623863bd4ae86ed1bb97cef0ef56bd417bd0d49507ef47d16af7b4e"}
    experimental_model
    Liver-specific Pcx-knockout mice
    exposure
    Genetic deletion of hepatic pyruvate carboxylase
    limitations
    Genetic enzyme deletion is not a dietary biotin experiment. Cross-nutrient implications identify pathway dependence rather than a proven supplement response.
    nutrient_topic
    Biotin research collection; topical membership is not evidence of a direct dietary effect. · Biotin
    organism
    Mus musculus
    plain_language
    Failure of this carbon-supply step can affect the niacin-derived reducing-power pool.
    primary_references
    [b7-p31006591] Pyruvate-Carboxylase-Mediated Anaplerosis Promotes Antioxidant Capacity by Sustaining TCA Cycle and Redox Metabolism in Liver. (2019). https://pubmed.ncbi.nlm.nih.gov/31006591/ DOI: 10.1016/j.cmet.2019.03.014
    tissue_or_cell_type
    Liver and systemic metabolism
    trigger_kind
    machinery_impairment Imported condition classification; unverified.

    Biotin: carboxylases, recycling, deficiency and nutrient interactions (2026-09-17) · lines 832–843

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Liver-specific Pcx-knockout mice · source_derived_draft · unverified_draft

    ### b7-pc-null-nadph Liver-specific Pcx deletion depleted hepatic NADPH and worsened oxidative stress. Condition category: machinery_impairment nutrient_topic: Biotin research collection; topical membership is not evidence of a direct dietary effect. plain_language: Failure of this carbon-supply step can affect the niacin-derived reducing-power pool. organism: Mus musculus tissue_or_cell_type: Liver and systemic metabolism experimental_model: Liver-specific Pcx-knockout mice limitations: Genetic enzyme deletion is not a dietary biotin experiment. Cross-nutrient implications identify pathway dependence rather than a proven supplement response. exposure: Genetic deletion of hepatic pyruvate carboxylase evidence_span: {"source_cache": "artifacts/biotin-research/31006591.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "0dcedbfac623863bd4ae86ed1bb97cef0ef56bd417bd0d49507ef47d16af7b4e", "start_char": 0, "end_char": 1141, "text_sha256": "0dcedbfac623863bd4ae86ed1bb97cef0ef56bd417bd0d49507ef47d16af7b4e"} [b7-p31006591] Pyruvate-Carboxylase-Mediated Anaplerosis Promotes Antioxidant Capacity by Sustaining TCA Cycle and Redox Metabolism in Liver. (2019). https://pubmed.ncbi.nlm.nih.gov/31006591/ DOI: 10.1016/j.cmet.2019.03.014
    Complete structured claim and evidence

  2. Adding 7.8 g/day leucine during repletion did not change end-period erythrocyte NAD or NADP or plasma tryptophan in this study.

    L-Leucine → Erythrocyte NAD content source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    Niacin (vitamin B3) (repleted_nutrient); L-Tryptophan (measured_precursor); Oxidized nicotinamide adenine dinucleotide phosphate (co_measured_pool)
    evidence_span
    {"source_cache": "artifacts/niacin-clinical-sources/fu1989.abstract.txt", "locator": "Indexed primary abstract", "file_sha256": "ca6d94c101aca84f1e41f35898434f44770ca563c5bff986fe52e33f797b0fbc", "start_char": 0, "end_char": 1340, "text_sha256": "ca6d94c101aca84f1e41f35898434f44770ca563c5bff986fe52e33f797b0fbc"}
    experimental_model
    Controlled metabolic-unit feeding; seven men, 80 days
    exposure
    6.1 or 10.1 niacin equivalents/day, followed by adequate/high intakes; repletion with or without 7.8 g/day leucine
    limitations
    Small controlled male metabolic-unit study. Erythrocytes are not every tissue; historical adequate intake is not a current recommendation. Jacob and Fu reports may describe related participants and are not counted as independent trials.
    nutrient_topic
    Niacin research collection; topical membership is not evidence of a direct dietary effect. · Niacin (vitamin B3)
    organism
    Homo sapiens
    plain_language
    Extra leucine did not block niacin recovery under this tested diet.
    primary_references
    [nia-clin-fu1989] Biochemical markers for assessment of niacin status in young men: levels of erythrocyte niacin coenzymes and plasma tryptophan. (1989). https://pubmed.ncbi.nlm.nih.gov/2621487/ DOI: 10.1093/jn/119.12.1949
    tissue_or_cell_type
    Erythrocytes and plasma

    Niacin: NAD metabolism, deficiency and nutrient interactions (2026-09-17) · lines 1135–1147

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Controlled metabolic-unit feeding; seven men, 80 days · source_derived_draft · unverified_draft

    ### nia-clin-leucine-repletion Adding 7.8 g/day leucine during repletion did not change end-period erythrocyte NAD or NADP or plasma tryptophan in this study. Condition category: normal nutrient_topic: Niacin research collection; topical membership is not evidence of a direct dietary effect. plain_language: Extra leucine did not block niacin recovery under this tested diet. organism: Homo sapiens tissue_or_cell_type: Erythrocytes and plasma experimental_model: Controlled metabolic-unit feeding; seven men, 80 days limitations: Small controlled male metabolic-unit study. Erythrocytes are not every tissue; historical adequate intake is not a current recommendation. Jacob and Fu reports may describe related participants and are not counted as independent trials. exposure: 6.1 or 10.1 niacin equivalents/day, followed by adequate/high intakes; repletion with or without 7.8 g/day leucine cross_nutrient: Niacin (vitamin B3) (repleted_nutrient); L-Tryptophan (measured_precursor); Oxidized nicotinamide adenine dinucleotide phosphate (co_measured_pool) evidence_span: {"source_cache": "artifacts/niacin-clinical-sources/fu1989.abstract.txt", "locator": "Indexed primary abstract", "file_sha256": "ca6d94c101aca84f1e41f35898434f44770ca563c5bff986fe52e33f797b0fbc", "start_char": 0, "end_char": 1340, "text_sha256": "ca6d94c101aca84f1e41f35898434f44770ca563c5bff986fe52e33f797b0fbc"} [nia-clin-fu1989] Biochemical markers for assessment of niacin status in young men: levels of erythrocyte niacin coenzymes and plasma tryptophan. (1989). https://pubmed.ncbi.nlm.nih.gov/2621487/ DOI: 10.1093/jn/119.12.1949
    Complete structured claim and evidence

  3. In the two subjects treated with niacinamide, subjective improvement began within 24–48 hours; oral lesions generally healed within a week, while tongue papillae and some skin lesions took longer.

    Nicotinamide → Pellagra clinical lesions source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    nutrient_deficiency Imported condition classification; unverified.
    cross_nutrient
    Niacin (vitamin B3) (repleted_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": 16399, "end_char": 17420, "text_sha256": "6b1cded5e0f16d68d3efb6aed24a292273030279ca9d21168b0ca00aa529e0c1"}
    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; Table IV: subject 4 began niacinamide 10 mg three times daily, later 50 mg three times daily; subject 5 received a 50 mg test dose, then 10 mg three times daily, later 25 mg three times daily. Historical study regimens, not individualized treatment instructions.
    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
    Replacing the missing precursor helped, but different tissues recovered at different speeds.
    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": 17970, "end_char": 19288, "file_sha256": "2d4004fb5985f80c8e44909506e1aa05b6eefd838f4c28102beac30fb3092bc5", "text_sha256": "238677e2a2fecb4a81c2eed519676bf50bb7d9a3884042ec46934c8a3a570c3a", "locator": "Table IV: subject-specific niacinamide regimens"}]
    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 1220–1233

    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-niacinamide-recovery In the two subjects treated with niacinamide, subjective improvement began within 24–48 hours; oral lesions generally healed within a week, while tongue papillae and some skin lesions took longer. Condition category: nutrient_deficiency nutrient_topic: Niacin research collection; topical membership is not evidence of a direct dietary effect. plain_language: Replacing the missing precursor helped, but different tissues recovered at different speeds. 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; Table IV: subject 4 began niacinamide 10 mg three times daily, later 50 mg three times daily; subject 5 received a 50 mg test dose, then 10 mg three times daily, later 25 mg three times daily. Historical study regimens, not individualized treatment instructions. cross_nutrient: Niacin (vitamin B3) (repleted_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": 16399, "end_char": 17420, "text_sha256": "6b1cded5e0f16d68d3efb6aed24a292273030279ca9d21168b0ca00aa529e0c1"} supplementary_evidence_spans: [{"source_cache": "artifacts/niacin-clinical-sources/goldsmith1952.txt", "start_char": 17970, "end_char": 19288, "file_sha256": "2d4004fb5985f80c8e44909506e1aa05b6eefd838f4c28102beac30fb3092bc5", "text_sha256": "238677e2a2fecb4a81c2eed519676bf50bb7d9a3884042ec46934c8a3a570c3a", "locator": "Table IV: subject-specific niacinamide regimens"}] [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
    Complete structured claim and evidence

In the sources

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    This is a research prototype built from draft material. It is not medical advice, and its statements still await verification against the original studies.

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