Vitamin A

availability_state

nutrient_deficiency Imported condition classification; unverified.

evidence_span

{"source_cache": "artifacts/lycopene-research/37269907.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "36b39754d4d3b4ed8721a15f8dffe03bfd387dcbef3ff50918daabb45c48e756", "start_char": 0, "end_char": 1986, "text_sha256": "36b39754d4d3b4ed8721a15f8dffe03bfd387dcbef3ff50918daabb45c48e756"}

experimental_model

Carotenoid-enzyme knockout comparison and vitamin-A diet experiment

exposure

1 mg lycopene in cottonseed oil daily for two weeks; separate vitamin-A-deficient versus sufficient diets

limitations

Mouse knockout distribution does not directly quantify human cleavage; increased ISX signaling does not prove conversion to vitamin A.

nutrient_topic

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

organism

Mouse

plain_language

A shortage of one nutrient can change the handling of another compound.

primary_references

[lycopene-p37269907] Lycopene Accumulation in Transgenic Mice Lacking One or Both Carotenoid Cleaving Enzymes. (2023). https://pubmed.ncbi.nlm.nih.gov/37269907/ DOI: 10.1016/j.tjnut.2023.05.025

tissue_or_cell_type

Liver, other tissues and intestinal gene expression

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Lycopene: absorption, metabolism, nutrient connections and human outcomes (2026-09-17) · lines 806–817

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Carotenoid-enzyme knockout comparison and vitamin-A diet experiment · source_derived_draft · unverified_draft

### lycopene-vitamin-a-status Vitamin-A-deficient wild-type mice accumulated more hepatic lycopene than vitamin-A-sufficient mice. Condition category: nutrient_deficiency nutrient_topic: Lycopene research collection; topical membership is not evidence of a direct dietary effect. plain_language: A shortage of one nutrient can change the handling of another compound. organism: Mouse tissue_or_cell_type: Liver, other tissues and intestinal gene expression experimental_model: Carotenoid-enzyme knockout comparison and vitamin-A diet experiment limitations: Mouse knockout distribution does not directly quantify human cleavage; increased ISX signaling does not prove conversion to vitamin A. exposure: 1 mg lycopene in cottonseed oil daily for two weeks; separate vitamin-A-deficient versus sufficient diets evidence_span: {"source_cache": "artifacts/lycopene-research/37269907.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "36b39754d4d3b4ed8721a15f8dffe03bfd387dcbef3ff50918daabb45c48e756", "start_char": 0, "end_char": 1986, "text_sha256": "36b39754d4d3b4ed8721a15f8dffe03bfd387dcbef3ff50918daabb45c48e756"} [lycopene-p37269907] Lycopene Accumulation in Transgenic Mice Lacking One or Both Carotenoid Cleaving Enzymes. (2023). https://pubmed.ncbi.nlm.nih.gov/37269907/ DOI: 10.1016/j.tjnut.2023.05.025

availability_state

nutrient_deficiency Imported condition classification; unverified.

experimental_model

Before/after repletion follow-up

limitations

Uncontrolled treatment observation; no dose recommendation.

nutrient_topic

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

organism

Homo sapiens

plain_language

Repletion reversed the measured visual deficit in this series.

primary_references

[kemp-1988] Visual function and rhodopsin levels in humans with vitamin A deficiency (1988). https://pubmed.ncbi.nlm.nih.gov/3350064/ DOI: 10.1016/S0014-4835(88)80076-9

tissue_or_cell_type

Retina

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1019–1028

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Before/after repletion follow-up · source_derived_draft · unverified_draft

### a-vision-deficiency-repletion Visual function normalized within eight days of vitamin A treatment in the three reported deficient patients. Condition category: nutrient_deficiency nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Repletion reversed the measured visual deficit in this series. organism: Homo sapiens tissue_or_cell_type: Retina experimental_model: Before/after repletion follow-up limitations: Uncontrolled treatment observation; no dose recommendation. [kemp-1988] Visual function and rhodopsin levels in humans with vitamin A deficiency (1988). https://pubmed.ncbi.nlm.nih.gov/3350064/ DOI: 10.1016/S0014-4835(88)80076-9

availability_state

nutrient_deficiency Imported condition classification; unverified.

experimental_model

Adaptometry and fundus reflectometry

limitations

Disease-associated deficiency; no general threshold or intake estimate.

nutrient_topic

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

organism

Homo sapiens

plain_language

Pigment recovery slowed when vitamin A was depleted.

primary_references

[kemp-1988] Visual function and rhodopsin levels in humans with vitamin A deficiency (1988). https://pubmed.ncbi.nlm.nih.gov/3350064/ DOI: 10.1016/S0014-4835(88)80076-9

tissue_or_cell_type

Mid-peripheral retina

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 997–1006

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Adaptometry and fundus reflectometry · source_derived_draft · unverified_draft

### a-vision-deficiency-rhodopsin In three vitamin A-deficient patients, slow rod dark adaptation accompanied abnormally slow rhodopsin regeneration. Condition category: nutrient_deficiency nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Pigment recovery slowed when vitamin A was depleted. organism: Homo sapiens tissue_or_cell_type: Mid-peripheral retina experimental_model: Adaptometry and fundus reflectometry limitations: Disease-associated deficiency; no general threshold or intake estimate. [kemp-1988] Visual function and rhodopsin levels in humans with vitamin A deficiency (1988). https://pubmed.ncbi.nlm.nih.gov/3350064/ DOI: 10.1016/S0014-4835(88)80076-9

availability_state

nutrient_deficiency Imported condition classification; unverified.

experimental_model

Baseline visual function

limitations

Clinical series of three, not a population effect size.

nutrient_topic

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

organism

Homo sapiens

plain_language

Severe depletion impaired night vision and also slowed cone recovery.

primary_references

[kemp-1988] Visual function and rhodopsin levels in humans with vitamin A deficiency (1988). https://pubmed.ncbi.nlm.nih.gov/3350064/ DOI: 10.1016/S0014-4835(88)80076-9

tissue_or_cell_type

Retina

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1008–1017

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Baseline visual function · source_derived_draft · unverified_draft

### a-vision-deficiency-sensitivity All three deficient patients initially lacked measurable rod function and had delayed cone adaptation. Condition category: nutrient_deficiency nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Severe depletion impaired night vision and also slowed cone recovery. organism: Homo sapiens tissue_or_cell_type: Retina experimental_model: Baseline visual function limitations: Clinical series of three, not a population effect size. [kemp-1988] Visual function and rhodopsin levels in humans with vitamin A deficiency (1988). https://pubmed.ncbi.nlm.nih.gov/3350064/ DOI: 10.1016/S0014-4835(88)80076-9

experimental_model

Dietary supplementation versus control; biochemical and morphologic endpoints

exposure

dietary vitamin A excess/supplementation

genotype

wild type and Abca4-null

limitations

Mouse exposure; no human dose or treatment recommendation follows. Degeneration depended on pigmentation and occurred on both diets.

nutrient_topic

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

organism

Mus musculus

plain_language

Extra vitamin A increased visual-cycle by-products in these mice.

primary_references

[radu-2008] Accelerated accumulation of lipofuscin pigments in the RPE of a mouse model for ABCA4-mediated retinal dystrophies following Vitamin A supplementation (2008). https://pubmed.ncbi.nlm.nih.gov/18515570/ DOI: 10.1167/iovs.07-1470

tissue_or_cell_type

Eye/RPE

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 847–858

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Dietary supplementation versus control; biochemical and morphologic endpoints · source_derived_draft · unverified_draft

### a-vision-excess-bisretinoids Vitamin A-supplemented diets increased ocular A2E/bisretinoid accumulation in wild-type and Abca4-null mice relative to control diets. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Extra vitamin A increased visual-cycle by-products in these mice. organism: Mus musculus tissue_or_cell_type: Eye/RPE experimental_model: Dietary supplementation versus control; biochemical and morphologic endpoints limitations: Mouse exposure; no human dose or treatment recommendation follows. Degeneration depended on pigmentation and occurred on both diets. exposure: dietary vitamin A excess/supplementation genotype: wild type and Abca4-null [radu-2008] Accelerated accumulation of lipofuscin pigments in the RPE of a mouse model for ABCA4-mediated retinal dystrophies following Vitamin A supplementation (2008). https://pubmed.ncbi.nlm.nih.gov/18515570/ DOI: 10.1167/iovs.07-1470

experimental_model

41 selected clinical cases with liver histology.

exposure

Chronic preformed-vitamin-A exposure; excess, not deficiency.

limitations

Case series cannot estimate population incidence or define a safe-dose threshold.

nutrient_topic

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

organism

Homo sapiens

plain_language

Prolonged excess can damage the organ that stores vitamin A.

primary_references

[va-geubel1991] Liver damage caused by therapeutic vitamin A administration: estimate of dose-related toxicity in 41 cases (1991). https://pubmed.ncbi.nlm.nih.gov/2019375/ DOI: 10.1016/0016-5085(91)90672-8

tissue_or_cell_type

Liver

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1834–1844

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · 41 selected clinical cases with liver histology. · source_derived_draft · unverified_draft

### va-chronic-excess-liver-injury Chronic vitamin A hepatotoxicity cases included cirrhosis and portal hypertension with characteristic hepatic storage-cell changes. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Prolonged excess can damage the organ that stores vitamin A. organism: Homo sapiens tissue_or_cell_type: Liver experimental_model: 41 selected clinical cases with liver histology. limitations: Case series cannot estimate population incidence or define a safe-dose threshold. exposure: Chronic preformed-vitamin-A exposure; excess, not deficiency. [va-geubel1991] Liver damage caused by therapeutic vitamin A administration: estimate of dose-related toxicity in 41 cases (1991). https://pubmed.ncbi.nlm.nih.gov/2019375/ DOI: 10.1016/0016-5085(91)90672-8

availability_state

nutrient_deficiency Imported condition classification; unverified.

experimental_model

Renal gene-expression assay.

limitations

Does not by itself measure circulating EPO or prove ineffective erythropoiesis mediation.

nutrient_topic

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

organism

Rattus norvegicus

plain_language

A shortage affected expression of an erythropoietic signal.

primary_references

[va-cunha2014] Vitamin A deficiency modulates iron metabolism via ineffective erythropoiesis (2014). https://pubmed.ncbi.nlm.nih.gov/24998947/ DOI: 10.1016/j.jnutbio.2014.05.005

tissue_or_cell_type

Kidney

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1755–1764

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Renal gene-expression assay. · source_derived_draft · unverified_draft

### va-deficiency-epo-transcript Vitamin A deficiency reduced renal Epo mRNA in the rat experiment. Condition category: nutrient_deficiency nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: A shortage affected expression of an erythropoietic signal. organism: Rattus norvegicus tissue_or_cell_type: Kidney experimental_model: Renal gene-expression assay. limitations: Does not by itself measure circulating EPO or prove ineffective erythropoiesis mediation. [va-cunha2014] Vitamin A deficiency modulates iron metabolism via ineffective erythropoiesis (2014). https://pubmed.ncbi.nlm.nih.gov/24998947/ DOI: 10.1016/j.jnutbio.2014.05.005

availability_state

nutrient_deficiency Imported condition classification; unverified.

experimental_model

Intestinal mRNA assay.

limitations

Does not quantify ferroportin membrane protein or iron-export flux.

nutrient_topic

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

organism

Rattus norvegicus

plain_language

Expression of an iron-export component changed alongside systemic signals.

primary_references

[va-cunha2016] Vitamin A deficiency modulates iron metabolism independent of hemojuvelin (Hfe2) and bone morphogenetic protein 6 (Bmp6) transcript levels (2016). https://pubmed.ncbi.nlm.nih.gov/27551308/ DOI: 10.1186/s12263-016-0519-4

tissue_or_cell_type

Small intestine

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1778–1787

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Intestinal mRNA assay. · source_derived_draft · unverified_draft

### va-deficiency-ferroportin-transcript Vitamin A deficiency reduced intestinal Fpn1 transcripts in the same rat study. Condition category: nutrient_deficiency nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Expression of an iron-export component changed alongside systemic signals. organism: Rattus norvegicus tissue_or_cell_type: Small intestine experimental_model: Intestinal mRNA assay. limitations: Does not quantify ferroportin membrane protein or iron-export flux. [va-cunha2016] Vitamin A deficiency modulates iron metabolism independent of hemojuvelin (Hfe2) and bone morphogenetic protein 6 (Bmp6) transcript levels (2016). https://pubmed.ncbi.nlm.nih.gov/27551308/ DOI: 10.1186/s12263-016-0519-4

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

Vitamin A/iron -> hepcidin regulation.

experimental_model

Dietary comparison; hepatic mRNA.

limitations

Not a direct demonstration of BMP signaling flux or circulating hepcidin.

nutrient_topic

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

organism

Rattus norvegicus

plain_language

The measured regulatory signals did not all move in the same direction.

primary_references

[va-cunha2016] Vitamin A deficiency modulates iron metabolism independent of hemojuvelin (Hfe2) and bone morphogenetic protein 6 (Bmp6) transcript levels (2016). https://pubmed.ncbi.nlm.nih.gov/27551308/ DOI: 10.1186/s12263-016-0519-4

tissue_or_cell_type

Liver

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1766–1776

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Dietary comparison; hepatic mRNA. · source_derived_draft · unverified_draft

### va-deficiency-hepcidin-transcript Vitamin A-deficient rats showed lower hepatic Hamp transcripts despite increased Bmp6 and Hfe2 transcripts. Condition category: nutrient_deficiency nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: The measured regulatory signals did not all move in the same direction. organism: Rattus norvegicus tissue_or_cell_type: Liver experimental_model: Dietary comparison; hepatic mRNA. limitations: Not a direct demonstration of BMP signaling flux or circulating hepcidin. cross_nutrient: Vitamin A/iron -> hepcidin regulation. [va-cunha2016] Vitamin A deficiency modulates iron metabolism independent of hemojuvelin (Hfe2) and bone morphogenetic protein 6 (Bmp6) transcript levels (2016). https://pubmed.ncbi.nlm.nih.gov/27551308/ DOI: 10.1186/s12263-016-0519-4

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

Vitamin A deficiency -> iron distribution.

experimental_model

Controlled rat dietary groups.

limitations

Erythrophagocytosis is a proposed explanation, not a fully isolated causal sequence.

nutrient_topic

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

organism

Rattus norvegicus

plain_language

Iron could be retained in one tissue while circulating availability fell.

primary_references

[va-cunha2014] Vitamin A deficiency modulates iron metabolism via ineffective erythropoiesis (2014). https://pubmed.ncbi.nlm.nih.gov/24998947/ DOI: 10.1016/j.jnutbio.2014.05.005

tissue_or_cell_type

Spleen and serum

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1743–1753

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Controlled rat dietary groups. · source_derived_draft · unverified_draft

### va-deficiency-iron-sequestration Vitamin A-deficient rats had more splenic iron but lower serum iron and transferrin saturation. Condition category: nutrient_deficiency nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Iron could be retained in one tissue while circulating availability fell. organism: Rattus norvegicus tissue_or_cell_type: Spleen and serum experimental_model: Controlled rat dietary groups. limitations: Erythrophagocytosis is a proposed explanation, not a fully isolated causal sequence. cross_nutrient: Vitamin A deficiency -> iron distribution. [va-cunha2014] Vitamin A deficiency modulates iron metabolism via ineffective erythropoiesis (2014). https://pubmed.ncbi.nlm.nih.gov/24998947/ DOI: 10.1016/j.jnutbio.2014.05.005

cross_nutrient

Vitamin A/carotene -> iron absorption; contested.

experimental_model

Six human cereal-meal studies.

limitations

Not consistently replicated; the claimed iron-complex mechanism was proposed rather than structurally demonstrated.

nutrient_topic

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

organism

Homo sapiens

plain_language

This study found that the meal additives made more iron available.

primary_references

[va-garciacasal1998] Vitamin A and beta-carotene can improve nonheme iron absorption from rice, wheat and corn by humans (1998). https://pubmed.ncbi.nlm.nih.gov/9482776/ DOI: 10.1093/jn/128.3.646

tissue_or_cell_type

Intestinal absorption

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1542–1552

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Six human cereal-meal studies. · source_derived_draft · unverified_draft

### va-iron-absorption-positive1998 Vitamin A and beta-carotene increased labelled nonheme iron absorption from tested cereal meals. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: This study found that the meal additives made more iron available. organism: Homo sapiens tissue_or_cell_type: Intestinal absorption experimental_model: Six human cereal-meal studies. limitations: Not consistently replicated; the claimed iron-complex mechanism was proposed rather than structurally demonstrated. cross_nutrient: Vitamin A/carotene -> iron absorption; contested. [va-garciacasal1998] Vitamin A and beta-carotene can improve nonheme iron absorption from rice, wheat and corn by humans (1998). https://pubmed.ncbi.nlm.nih.gov/9482776/ DOI: 10.1093/jn/128.3.646

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

Vitamin A/iron -> hemoglobin response.

experimental_model

Eight-week randomized trial.

limitations

Combined benefit does not prove a biochemical synergy or specify the cellular mediator.

nutrient_topic

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

organism

Homo sapiens

plain_language

Correcting more than one shortage improved the measured response in this population.

primary_references

[va-suharno1993] Supplementation with vitamin A and iron for nutritional anaemia in pregnant women in West Java, Indonesia (1993). https://pubmed.ncbi.nlm.nih.gov/7901636/ DOI: 10.1016/0140-6736(93)92246-p

tissue_or_cell_type

Blood

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1448–1458

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Eight-week randomized trial. · source_derived_draft · unverified_draft

### va-iron-combined-hemoglobin Combined vitamin A and iron produced the largest hemoglobin response in the factorial pregnancy trial. Condition category: nutrient_deficiency nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Correcting more than one shortage improved the measured response in this population. organism: Homo sapiens tissue_or_cell_type: Blood experimental_model: Eight-week randomized trial. limitations: Combined benefit does not prove a biochemical synergy or specify the cellular mediator. cross_nutrient: Vitamin A/iron -> hemoglobin response. [va-suharno1993] Supplementation with vitamin A and iron for nutritional anaemia in pregnant women in West Java, Indonesia (1993). https://pubmed.ncbi.nlm.nih.gov/7901636/ DOI: 10.1016/0140-6736(93)92246-p

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

Vitamin A -> EPO/iron use.

experimental_model

Randomized ten-month follow-up.

limitations

EPO was measured, not blocked; its mediation of the hemoglobin response remains inferred.

nutrient_topic

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

organism

Homo sapiens

plain_language

Vitamin A can influence the signal that supports red-cell production.

primary_references

[va-zimmermann2006-iron] Vitamin A supplementation in children with poor vitamin A and iron status increases erythropoietin and hemoglobin concentrations without changing total body iron (2006). https://pubmed.ncbi.nlm.nih.gov/16960172/ DOI: 10.1093/ajcn/84.3.580

tissue_or_cell_type

Blood

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1460–1470

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Randomized ten-month follow-up. · source_derived_draft · unverified_draft

### va-repletion-erythropoietin Vitamin A increased circulating EPO and hemoglobin in schoolchildren with poor nutrient status. Condition category: nutrient_deficiency nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Vitamin A can influence the signal that supports red-cell production. organism: Homo sapiens tissue_or_cell_type: Blood experimental_model: Randomized ten-month follow-up. limitations: EPO was measured, not blocked; its mediation of the hemoglobin response remains inferred. cross_nutrient: Vitamin A -> EPO/iron use. [va-zimmermann2006-iron] Vitamin A supplementation in children with poor vitamin A and iron status increases erythropoietin and hemoglobin concentrations without changing total body iron (2006). https://pubmed.ncbi.nlm.nih.gov/16960172/ DOI: 10.1093/ajcn/84.3.580

availability_state

nutrient_deficiency Imported condition classification; unverified.

experimental_model

Ferritin/transferrin-receptor-based estimates.

limitations

Redistribution is an interpretation; liver iron was not directly biopsied.

nutrient_topic

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

organism

Homo sapiens

plain_language

A better blood count did not require a measured increase in total-body iron.

primary_references

[va-zimmermann2006-iron] Vitamin A supplementation in children with poor vitamin A and iron status increases erythropoietin and hemoglobin concentrations without changing total body iron (2006). https://pubmed.ncbi.nlm.nih.gov/16960172/ DOI: 10.1093/ajcn/84.3.580

tissue_or_cell_type

Blood; inferred storage

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1472–1481

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Ferritin/transferrin-receptor-based estimates. · source_derived_draft · unverified_draft

### va-repletion-iron-store-redistribution Ferritin fell while calculated total-body iron remained unchanged in the same trial, consistent with redistribution of existing iron. Condition category: nutrient_deficiency nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: A better blood count did not require a measured increase in total-body iron. organism: Homo sapiens tissue_or_cell_type: Blood; inferred storage experimental_model: Ferritin/transferrin-receptor-based estimates. limitations: Redistribution is an interpretation; liver iron was not directly biopsied. [va-zimmermann2006-iron] Vitamin A supplementation in children with poor vitamin A and iron status increases erythropoietin and hemoglobin concentrations without changing total body iron (2006). https://pubmed.ncbi.nlm.nih.gov/16960172/ DOI: 10.1093/ajcn/84.3.580

availability_state

nutrient_deficiency Imported condition classification; unverified.

evidence_locator

Abstract

experimental_model

Mouse B-cell/dendritic-cell systems and vitamin A-deficient mice.

exposure

Vitamin A-deficient diet

limitations

Migration and differentiation contributions are not interchangeable.

nutrient_topic

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

organism

Mus musculus

plain_language

Depletion reduced the local antibody-secreting cell compartment.

primary_references

[va-mora-2006] Generation of gut-homing IgA-secreting B cells by intestinal dendritic cells (2006). https://pubmed.ncbi.nlm.nih.gov/17110582/ DOI: 10.1126/science.1132742

tissue_or_cell_type

Small intestine

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1240–1251

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Mouse B-cell/dendritic-cell systems and vitamin A-deficient mice. · source_derived_draft · unverified_draft

### va-sig-deficient-intestinal-iga Vitamin A-deficient mice lacked IgA-secreting cells in the small intestine. Condition category: nutrient_deficiency nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Depletion reduced the local antibody-secreting cell compartment. organism: Mus musculus tissue_or_cell_type: Small intestine experimental_model: Mouse B-cell/dendritic-cell systems and vitamin A-deficient mice. limitations: Migration and differentiation contributions are not interchangeable. evidence_locator: Abstract exposure: Vitamin A-deficient diet [va-mora-2006] Generation of gut-homing IgA-secreting B cells by intestinal dendritic cells (2006). https://pubmed.ncbi.nlm.nih.gov/17110582/ DOI: 10.1126/science.1132742

availability_state

nutrient_deficiency Imported condition classification; unverified.

evidence_locator

Abstract

experimental_model

Mouse activated T cells, gut dendritic cells and vitamin A-deficient mice.

exposure

Vitamin A-deficient diet

limitations

Does not isolate trafficking from all other deficiency effects.

nutrient_topic

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

organism

Mus musculus

plain_language

Dietary depletion changed the intestinal T-cell compartment.

primary_references

[va-iwata-2004] Retinoic acid imprints gut-homing specificity on T cells (2004). https://pubmed.ncbi.nlm.nih.gov/15485630/ DOI: 10.1016/j.immuni.2004.08.011

tissue_or_cell_type

Intestinal lamina propria

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1201–1212

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Mouse activated T cells, gut dendritic cells and vitamin A-deficient mice. · source_derived_draft · unverified_draft

### va-sig-deficient-intestinal-t-cells Vitamin A-deficient mice had depleted intestinal lamina propria T cells. Condition category: nutrient_deficiency nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Dietary depletion changed the intestinal T-cell compartment. organism: Mus musculus tissue_or_cell_type: Intestinal lamina propria experimental_model: Mouse activated T cells, gut dendritic cells and vitamin A-deficient mice. limitations: Does not isolate trafficking from all other deficiency effects. evidence_locator: Abstract exposure: Vitamin A-deficient diet [va-iwata-2004] Retinoic acid imprints gut-homing specificity on T cells (2004). https://pubmed.ncbi.nlm.nih.gov/15485630/ DOI: 10.1016/j.immuni.2004.08.011

availability_state

machinery_impairment Imported condition classification; unverified.

cross_nutrient

true

experimental_model

Six-patient long-term abetalipoproteinemia case series

exposure

Large oral vitamin E doses for 12–18 years alongside low-fat diet and other fat-soluble vitamins; exact dose absent from the abstract.

limitations

Uncontrolled co-treatment series; cannot isolate vitamin E effect or demonstrate nutrient synergy. Genetic lipid transport disease differs from simple low intake.

nutrient_topic

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

organism

Homo sapiens

plain_language

In this transport disease, vitamin A alone did not substitute for the broader treatment that included vitamin E.

primary_references

[e-clin-retina1986] Oral vitamin E supplements can prevent the retinopathy of abetalipoproteinaemia. (1986). https://pubmed.ncbi.nlm.nih.gov/3954973/ DOI: 10.1136/bjo.70.3.166

tissue_or_cell_type

Retina

trigger_kind

machinery_impairment Imported condition classification; unverified.

Vitamin E: transport, membrane protection and nutrient interactions (2026-09-17) · lines 1453–1464

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Six-patient long-term abetalipoproteinemia case series · source_derived_draft · unverified_draft

### e-clin-abetalipo-a-alone The six-patient abetalipoproteinemia report noted that vitamin A alone had not prevented or arrested the retinal lesion, whereas long-term regimens including vitamin E modified its course. Condition category: machinery_impairment nutrient_topic: Vitamin E research collection; topical membership is not evidence of a direct dietary effect. plain_language: In this transport disease, vitamin A alone did not substitute for the broader treatment that included vitamin E. organism: Homo sapiens tissue_or_cell_type: Retina experimental_model: Six-patient long-term abetalipoproteinemia case series limitations: Uncontrolled co-treatment series; cannot isolate vitamin E effect or demonstrate nutrient synergy. Genetic lipid transport disease differs from simple low intake. exposure: Large oral vitamin E doses for 12–18 years alongside low-fat diet and other fat-soluble vitamins; exact dose absent from the abstract. cross_nutrient: true [e-clin-retina1986] Oral vitamin E supplements can prevent the retinopathy of abetalipoproteinaemia. (1986). https://pubmed.ncbi.nlm.nih.gov/3954973/ DOI: 10.1136/bjo.70.3.166

dose

Pureed labeled Moringa leaves providing 1 mg beta-carotene plus a reference retinyl-acetate dose

duration

Thirty-five-day isotope sampling

evidence_access

Primary PubMed abstract and indexed metadata reviewed. Full-text method details not stated here remain unresolved.

evidence_scope

literature_reviewed; model-specific source-derived curation

experimental_model

Fifteen Mexican children aged 17-35 months

limitations

Children were well nourished with adequate vitamin A stores; the estimate may differ with deficiency, food matrix, genetics and infection.

nutrient_topic

Moringa oleifera chapter; interacting nutrients, drugs, peptides and proteins retain their experimental settings. · Moringa oleifera

organism

Fifteen Mexican children aged 17-35 months

plain_language

In fifteen well-nourished young children, intrinsically labeled beta-carotene from pureed Moringa leaves had 28% relative bioefficacy and an estimated vitamin A equivalence of 3.3:1 by weight.

primary_references

Use of a "Super-child" Approach to Assess the Vitamin A Equivalence of Moringa oleifera Leaves, Develop a Compartmental Model for Vitamin A Kinetics, and Estimate Vitamin A Total Body Stores in Young Mexican Children. (2017). https://pubmed.ncbi.nlm.nih.gov/28931584/ DOI: 10.3945/jn.117.256974

route

Oral

tissue

Stable-isotope plasma retinol kinetics

Moringa oleifera: mechanism of action and interactions (2026-09-20) · lines 233–242

Original AI-assisted source-specific curation with primary-study citations, model, exposure, route, duration, negative findings and limitations preserved. Not publisher full text. · supports · Fifteen Mexican children aged 17-35 months · source_derived_draft · unverified_draft

## moringa-child-vitamin-a-equivalence In fifteen well-nourished young children, intrinsically labeled beta-carotene from pureed Moringa leaves had 28% relative bioefficacy and an estimated vitamin A equivalence of 3.3:1 by weight. Model/species: Fifteen Mexican children aged 17-35 months Tissue/system: Stable-isotope plasma retinol kinetics Exposure: Pureed labeled Moringa leaves providing 1 mg beta-carotene plus a reference retinyl-acetate dose Route: Oral Duration: Thirty-five-day isotope sampling Limits: Children were well nourished with adequate vitamin A stores; the estimate may differ with deficiency, food matrix, genetics and infection. Primary reference: Use of a "Super-child" Approach to Assess the Vitamin A Equivalence of Moringa oleifera Leaves, Develop a Compartmental Model for Vitamin A Kinetics, and Estimate Vitamin A Total Body Stores in Young Mexican Children. (2017). https://pubmed.ncbi.nlm.nih.gov/28931584/ DOI: 10.3945/jn.117.256974 Access: Primary PubMed abstract and indexed metadata reviewed. Full-text method details not stated here remain unresolved.

dose

Two Moringa-fortified foods versus a cereal-legume control

duration

Six weeks

evidence_access

Primary PubMed abstract and indexed metadata reviewed. Full-text method details not stated here remain unresolved.

evidence_scope

literature_reviewed; model-specific source-derived curation

experimental_model

Sixty-five completing infant-mother pairs in Ghana

limitations

The pilot had substantial attrition and short follow-up; its null result does not contradict measured carotenoid conversion in well-nourished children.

nutrient_topic

Moringa oleifera chapter; interacting nutrients, drugs, peptides and proteins retain their experimental settings. · Moringa oleifera

organism

Sixty-five completing infant-mother pairs in Ghana

plain_language

In a six-week pilot feeding study, Moringa-fortified complementary foods produced only marginal, nonsignificant blood-retinol increases, and all infants remained vitamin A deficient.

primary_references

Improving Blood Retinol Concentrations with Complementary Foods Fortified with Moringa oleifera Leaf Powder - A Pilot Study. (2018). https://pubmed.ncbi.nlm.nih.gov/29962920/

route

Oral feeding

tissue

Whole-blood retinol

Moringa oleifera: mechanism of action and interactions (2026-09-20) · lines 244–253

Original AI-assisted source-specific curation with primary-study citations, model, exposure, route, duration, negative findings and limitations preserved. Not publisher full text. · supports · Sixty-five completing infant-mother pairs in Ghana · source_derived_draft · unverified_draft

## moringa-infant-retinol-null In a six-week pilot feeding study, Moringa-fortified complementary foods produced only marginal, nonsignificant blood-retinol increases, and all infants remained vitamin A deficient. Model/species: Sixty-five completing infant-mother pairs in Ghana Tissue/system: Whole-blood retinol Exposure: Two Moringa-fortified foods versus a cereal-legume control Route: Oral feeding Duration: Six weeks Limits: The pilot had substantial attrition and short follow-up; its null result does not contradict measured carotenoid conversion in well-nourished children. Primary reference: Improving Blood Retinol Concentrations with Complementary Foods Fortified with Moringa oleifera Leaf Powder - A Pilot Study. (2018). https://pubmed.ncbi.nlm.nih.gov/29962920/ Access: Primary PubMed abstract and indexed metadata reviewed. Full-text method details not stated here remain unresolved.

dose

Corn porridge with or without 20 g/day leaf powder

duration

Three months

evidence_access

Primary PubMed abstract and indexed metadata reviewed. Full-text method details not stated here remain unresolved.

evidence_scope

literature_reviewed; model-specific source-derived curation

experimental_model

Forty-four completing Kenyan breastfeeding mother-infant pairs

limitations

The small pilot had baseline alpha-carotene imbalance and was not powered to establish clinical infant benefit.

nutrient_topic

Moringa oleifera chapter; interacting nutrients, drugs, peptides and proteins retain their experimental settings. · Moringa oleifera

organism

Forty-four completing Kenyan breastfeeding mother-infant pairs

plain_language

In a three-month cluster-randomized pilot, 20 g/day maternal Moringa leaf powder did not change human-milk vitamin A concentration or maternal and infant serum vitamin A status, although milk alpha-carotene rose modestly.

primary_references

Impact of Maternal Moringa oleifera Leaf Supplementation on Milk and Serum Vitamin A and Carotenoid Concentrations in a Cohort of Breastfeeding Kenyan Women and Their Infants. (2024). https://pubmed.ncbi.nlm.nih.gov/39408390/ DOI: 10.3390/nu16193425

route

Maternal oral feeding

tissue

Milk retinol/carotenoids and serum retinol-binding protein

Moringa oleifera: mechanism of action and interactions (2026-09-20) · lines 255–264

Original AI-assisted source-specific curation with primary-study citations, model, exposure, route, duration, negative findings and limitations preserved. Not publisher full text. · supports · Forty-four completing Kenyan breastfeeding mother-infant pairs · source_derived_draft · unverified_draft

## moringa-maternal-milk-retinol-null In a three-month cluster-randomized pilot, 20 g/day maternal Moringa leaf powder did not change human-milk vitamin A concentration or maternal and infant serum vitamin A status, although milk alpha-carotene rose modestly. Model/species: Forty-four completing Kenyan breastfeeding mother-infant pairs Tissue/system: Milk retinol/carotenoids and serum retinol-binding protein Exposure: Corn porridge with or without 20 g/day leaf powder Route: Maternal oral feeding Duration: Three months Limits: The small pilot had baseline alpha-carotene imbalance and was not powered to establish clinical infant benefit. Primary reference: Impact of Maternal Moringa oleifera Leaf Supplementation on Milk and Serum Vitamin A and Carotenoid Concentrations in a Cohort of Breastfeeding Kenyan Women and Their Infants. (2024). https://pubmed.ncbi.nlm.nih.gov/39408390/ DOI: 10.3390/nu16193425 Access: Primary PubMed abstract and indexed metadata reviewed. Full-text method details not stated here remain unresolved.

availability_state

biomarker_context Imported condition classification; unverified.

evidence_span

{"source_cache": "artifacts/lycopene-research/15930452.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "3a90148eb83ff18442e37f9fd5ed31f44acbf8d7616ef05ff1e65e6e2d64e84f", "start_char": 0, "end_char": 1595, "text_sha256": "3a90148eb83ff18442e37f9fd5ed31f44acbf8d7616ef05ff1e65e6e2d64e84f"}

experimental_model

Randomized 36-week controlled diet study

exposure

Olestra substituted for one-third of fat energy; daily multivitamin and vitamin-E-fortified olestra

limitations

Exposure-specific depletion, not an established lycopene deficiency syndrome; reference-range limits are not clinical deficiency thresholds.

nutrient_topic

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

organism

Human, 37 healthy men

plain_language

Replacing dietary fat with a nonabsorbed substitute changed carotenoid exposure.

primary_references

[lycopene-p15930452] Daily intake of multivitamins during long-term intake of olestra in men prevents declines in serum vitamins A and E but not carotenoids. (2005). https://pubmed.ncbi.nlm.nih.gov/15930452/ DOI: 10.1093/jn/135.6.1456

tissue_or_cell_type

Serum carotenoids and fat-soluble vitamins

trigger_kind

biomarker_context Imported condition classification; unverified.

Lycopene: absorption, metabolism, nutrient connections and human outcomes (2026-09-17) · lines 858–869

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Randomized 36-week controlled diet study · source_derived_draft · unverified_draft

### lycopene-olestra-lycopene Olestra lowered serum lycopene by 12 weeks, persisting after cholesterol or BMI adjustment; the multivitamin did not prevent this. Condition category: biomarker_context nutrient_topic: Lycopene research collection; topical membership is not evidence of a direct dietary effect. plain_language: Replacing dietary fat with a nonabsorbed substitute changed carotenoid exposure. organism: Human, 37 healthy men tissue_or_cell_type: Serum carotenoids and fat-soluble vitamins experimental_model: Randomized 36-week controlled diet study limitations: Exposure-specific depletion, not an established lycopene deficiency syndrome; reference-range limits are not clinical deficiency thresholds. exposure: Olestra substituted for one-third of fat energy; daily multivitamin and vitamin-E-fortified olestra evidence_span: {"source_cache": "artifacts/lycopene-research/15930452.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "3a90148eb83ff18442e37f9fd5ed31f44acbf8d7616ef05ff1e65e6e2d64e84f", "start_char": 0, "end_char": 1595, "text_sha256": "3a90148eb83ff18442e37f9fd5ed31f44acbf8d7616ef05ff1e65e6e2d64e84f"} [lycopene-p15930452] Daily intake of multivitamins during long-term intake of olestra in men prevents declines in serum vitamins A and E but not carotenoids. (2005). https://pubmed.ncbi.nlm.nih.gov/15930452/ DOI: 10.1093/jn/135.6.1456

evidence_span

{"source_cache": "artifacts/acetate-research/27966553.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "25ef476e62dd28f354099501d2919c3f765aaddd89d1a05739e3e0dc703d11ac", "start_char": 0, "end_char": 1363, "text_sha256": "25ef476e62dd28f354099501d2919c3f765aaddd89d1a05739e3e0dc703d11ac"}

experimental_model

GPR43 knockout mice with B-cell and dendritic-cell coculture and retinoic acid signalling blockade

exposure

Dietary acetate or butyrate in wild-type and GPR43 knockout mice, with in vitro IgA class switching assays

limitations

A clean set of controls: butyrate did not substitute for acetate, the effect was independent of T cells, and blocking the downstream vitamin A metabolite removed it.

nutrient_topic

Acetic acid research collection; topical membership is not evidence of a direct clinical effect, and the ingested acid is recorded separately from the circulating acetate anion. · Acetic acid

organism

Mouse

plain_language

Acetate works by switching on the enzyme that turns vitamin A into its active form; block that and the effect is gone.

primary_references

[acetate-p27966553] Microbiota metabolite short-chain fatty acid acetate promotes intestinal IgA response to microbiota which is mediated by GPR43. (2017). https://pubmed.ncbi.nlm.nih.gov/27966553/ DOI: 10.1038/mi.2016.114

tissue_or_cell_type

Intestinal mucosa

Acetic acid: the ingested acid, the receptors acetate binds, the acetyl-CoA it becomes, and the acetyl groups that reach histones (2026-09-21) · lines 394–405

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · GPR43 knockout mice with B-cell and dendritic-cell coculture and retinoic acid signalling blockade · source_derived_draft · unverified_draft

### acetate-acetate-vitamin-a-route Acetate promoted B-cell IgA class switching and IgA production in vitro in the presence of wild-type but not GPR43 knockout dendritic cells, and mechanistically acetate induced dendritic-cell expression of Aldh1a2, which converts vitamin A into retinoic acid, with blockade of retinoic acid signalling inhibiting the acetate-induced IgA production. Condition category: normal nutrient_topic: Acetic acid research collection; topical membership is not evidence of a direct clinical effect, and the ingested acid is recorded separately from the circulating acetate anion. plain_language: Acetate works by switching on the enzyme that turns vitamin A into its active form; block that and the effect is gone. organism: Mouse tissue_or_cell_type: Intestinal mucosa experimental_model: GPR43 knockout mice with B-cell and dendritic-cell coculture and retinoic acid signalling blockade limitations: A clean set of controls: butyrate did not substitute for acetate, the effect was independent of T cells, and blocking the downstream vitamin A metabolite removed it. exposure: Dietary acetate or butyrate in wild-type and GPR43 knockout mice, with in vitro IgA class switching assays evidence_span: {"source_cache": "artifacts/acetate-research/27966553.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "25ef476e62dd28f354099501d2919c3f765aaddd89d1a05739e3e0dc703d11ac", "start_char": 0, "end_char": 1363, "text_sha256": "25ef476e62dd28f354099501d2919c3f765aaddd89d1a05739e3e0dc703d11ac"} [acetate-p27966553] Microbiota metabolite short-chain fatty acid acetate promotes intestinal IgA response to microbiota which is mediated by GPR43. (2017). https://pubmed.ncbi.nlm.nih.gov/27966553/ DOI: 10.1038/mi.2016.114

cross_nutrient

Retinoid/iron chemistry; hypothesis boundary retained.

experimental_model

Cell-free pH-shift experiment.

limitations

Solubility alone neither proves a defined retinoid-iron complex nor absorption in vivo.

nutrient_topic

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

organism

Homo sapiens

plain_language

A laboratory solubility result supported a proposed explanation for the meal findings.

primary_references

[va-garciacasal1998] Vitamin A and beta-carotene can improve nonheme iron absorption from rice, wheat and corn by humans (1998). https://pubmed.ncbi.nlm.nih.gov/9482776/ DOI: 10.1093/jn/128.3.646

tissue_or_cell_type

Cell-free chemistry

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1554–1564

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Cell-free pH-shift experiment. · source_derived_draft · unverified_draft

### va-retinoid-iron-solubility-assay Adding beta-carotene or vitamin A retained more iron in solution when the assay pH rose from acidic toward near-neutral. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: A laboratory solubility result supported a proposed explanation for the meal findings. organism: Homo sapiens tissue_or_cell_type: Cell-free chemistry experimental_model: Cell-free pH-shift experiment. limitations: Solubility alone neither proves a defined retinoid-iron complex nor absorption in vivo. cross_nutrient: Retinoid/iron chemistry; hypothesis boundary retained. [va-garciacasal1998] Vitamin A and beta-carotene can improve nonheme iron absorption from rice, wheat and corn by humans (1998). https://pubmed.ncbi.nlm.nih.gov/9482776/ DOI: 10.1093/jn/128.3.646

evidence_locator

Abstract

experimental_model

Transfected COS-1 nucleosol; ligand competition and chimeric receptor reporters.

exposure

Isomer competition

limitations

Does not establish endogenous tissue concentrations.

nutrient_topic

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

organism

Recombinant receptors in COS-1 cells

plain_language

An RXR-binding retinoid can also activate RAR pathways.

primary_references

[va-allenby-1993] Retinoic acid receptors and retinoid X receptors: interactions with endogenous retinoic acids (1993). https://pubmed.ncbi.nlm.nih.gov/8380496/ DOI: 10.1073/pnas.90.1.30

tissue_or_cell_type

Nuclear extracts

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1043–1054

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Transfected COS-1 nucleosol; ligand competition and chimeric receptor reporters. · source_derived_draft · unverified_draft

### va-sig-9cis-rar-binding 9-cis RA also bound RAR alpha, beta and gamma; it was not RXR-selective. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: An RXR-binding retinoid can also activate RAR pathways. organism: Recombinant receptors in COS-1 cells tissue_or_cell_type: Nuclear extracts experimental_model: Transfected COS-1 nucleosol; ligand competition and chimeric receptor reporters. limitations: Does not establish endogenous tissue concentrations. evidence_locator: Abstract exposure: Isomer competition [va-allenby-1993] Retinoic acid receptors and retinoid X receptors: interactions with endogenous retinoic acids (1993). https://pubmed.ncbi.nlm.nih.gov/8380496/ DOI: 10.1073/pnas.90.1.30

evidence_locator

Abstract

experimental_model

Receptor binding and cell transfection assays.

exposure

9-cis RA exposure

limitations

Its biochemical activity does not establish a universal physiological RXR ligand pool.

nutrient_topic

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

organism

Recombinant/cultured-cell system

plain_language

The 9-cis isomer supplies a direct experimental RXR ligand.

primary_references

[va-heyman-1992] 9-cis retinoic acid is a high affinity ligand for the retinoid X receptor (1992). https://pubmed.ncbi.nlm.nih.gov/1310260/ DOI: 10.1016/0092-8674(92)90479-v

tissue_or_cell_type

Receptor-binding preparations

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1069–1080

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Receptor binding and cell transfection assays. · source_derived_draft · unverified_draft

### va-sig-9cis-rxr-binding 9-cis RA bound the tested RXR preparation with high affinity and activated RXR-dependent reporter responses. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: The 9-cis isomer supplies a direct experimental RXR ligand. organism: Recombinant/cultured-cell system tissue_or_cell_type: Receptor-binding preparations experimental_model: Receptor binding and cell transfection assays. limitations: Its biochemical activity does not establish a universal physiological RXR ligand pool. evidence_locator: Abstract exposure: 9-cis RA exposure [va-heyman-1992] 9-cis retinoic acid is a high affinity ligand for the retinoid X receptor (1992). https://pubmed.ncbi.nlm.nih.gov/1310260/ DOI: 10.1016/0092-8674(92)90479-v

evidence_locator

Abstract

experimental_model

Transfected COS-1 nucleosol; ligand competition and chimeric receptor reporters.

exposure

Radioligand competition

limitations

Binding affinity is not a dietary threshold.

nutrient_topic

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

organism

Recombinant receptors in African green monkey COS-1 cells

plain_language

The all-trans isomer directly engages RAR proteins.

primary_references

[va-allenby-1993] Retinoic acid receptors and retinoid X receptors: interactions with endogenous retinoic acids (1993). https://pubmed.ncbi.nlm.nih.gov/8380496/ DOI: 10.1073/pnas.90.1.30

tissue_or_cell_type

Nuclear extracts

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1030–1041

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Transfected COS-1 nucleosol; ligand competition and chimeric receptor reporters. · source_derived_draft · unverified_draft

### va-sig-atra-rar-binding All-trans RA bound the tested RAR alpha, beta and gamma preparations with high affinity. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: The all-trans isomer directly engages RAR proteins. organism: Recombinant receptors in African green monkey COS-1 cells tissue_or_cell_type: Nuclear extracts experimental_model: Transfected COS-1 nucleosol; ligand competition and chimeric receptor reporters. limitations: Binding affinity is not a dietary threshold. evidence_locator: Abstract exposure: Radioligand competition [va-allenby-1993] Retinoic acid receptors and retinoid X receptors: interactions with endogenous retinoic acids (1993). https://pubmed.ncbi.nlm.nih.gov/8380496/ DOI: 10.1073/pnas.90.1.30

evidence_locator

Abstract

experimental_model

Transfected COS-1 nucleosol; ligand competition and chimeric receptor reporters.

exposure

Isomer competition

limitations

Cell metabolism can alter apparent reporter responses.

nutrient_topic

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

organism

Recombinant receptors in COS-1 cells

plain_language

RAR and RXR cannot be treated as interchangeable RA receptors.

primary_references

[va-allenby-1993] Retinoic acid receptors and retinoid X receptors: interactions with endogenous retinoic acids (1993). https://pubmed.ncbi.nlm.nih.gov/8380496/ DOI: 10.1073/pnas.90.1.30

tissue_or_cell_type

Nuclear extracts

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1056–1067

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Transfected COS-1 nucleosol; ligand competition and chimeric receptor reporters. · source_derived_draft · unverified_draft

### va-sig-atra-rxr-selectivity All-trans RA did not effectively compete for RXR binding in the tested isomer assay. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: RAR and RXR cannot be treated as interchangeable RA receptors. organism: Recombinant receptors in COS-1 cells tissue_or_cell_type: Nuclear extracts experimental_model: Transfected COS-1 nucleosol; ligand competition and chimeric receptor reporters. limitations: Cell metabolism can alter apparent reporter responses. evidence_locator: Abstract exposure: Isomer competition [va-allenby-1993] Retinoic acid receptors and retinoid X receptors: interactions with endogenous retinoic acids (1993). https://pubmed.ncbi.nlm.nih.gov/8380496/ DOI: 10.1073/pnas.90.1.30

evidence_locator

Abstract

experimental_model

Genetically encoded FRET RA sensors in living zebrafish embryos.

exposure

Genetically encoded RA sensors

limitations

Sensor affinity, developmental stage and model constrain interpretation.

nutrient_topic

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

organism

Danio rerio

plain_language

Embryonic cells encounter different local amounts of signaling RA.

primary_references

[va-shimozono-2013] Visualization of an endogenous retinoic acid gradient across embryonic development (2013). https://pubmed.ncbi.nlm.nih.gov/23563268/ DOI: 10.1038/nature12037

tissue_or_cell_type

Living early embryos

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1409–1420

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Genetically encoded FRET RA sensors in living zebrafish embryos. · source_derived_draft · unverified_draft

### va-sig-embryonic-ra-gradient FRET sensors visualized an endogenous RA concentration gradient during zebrafish gastrulation and somitogenesis. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Embryonic cells encounter different local amounts of signaling RA. organism: Danio rerio tissue_or_cell_type: Living early embryos experimental_model: Genetically encoded FRET RA sensors in living zebrafish embryos. limitations: Sensor affinity, developmental stage and model constrain interpretation. evidence_locator: Abstract exposure: Genetically encoded RA sensors [va-shimozono-2013] Visualization of an endogenous retinoic acid gradient across embryonic development (2013). https://pubmed.ncbi.nlm.nih.gov/23563268/ DOI: 10.1038/nature12037

evidence_locator

Abstract

experimental_model

RA-exposed preheadfold transgenic mouse embryos; lacZ and anatomy.

exposure

Experimental excess RA exposure

limitations

Not a quantitative human teratogenic threshold.

nutrient_topic

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

organism

Mus musculus

plain_language

Excess developmental signaling changed segment identity.

primary_references

[va-marshall-1992] Retinoic acid alters hindbrain Hox code and induces transformation of rhombomeres 2/3 into a 4/5 identity (1992). https://www.nature.com/articles/360737a0 DOI: 10.1038/360737a0

tissue_or_cell_type

Embryonic hindbrain

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1435–1446

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · RA-exposed preheadfold transgenic mouse embryos; lacZ and anatomy. · source_derived_draft · unverified_draft

### va-sig-excess-ra-hindbrain-identity The exposed embryos showed rhombomere 2/3 transformation toward 4/5 identity with matching anatomical changes. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Excess developmental signaling changed segment identity. organism: Mus musculus tissue_or_cell_type: Embryonic hindbrain experimental_model: RA-exposed preheadfold transgenic mouse embryos; lacZ and anatomy. limitations: Not a quantitative human teratogenic threshold. evidence_locator: Abstract exposure: Experimental excess RA exposure [va-marshall-1992] Retinoic acid alters hindbrain Hox code and induces transformation of rhombomeres 2/3 into a 4/5 identity (1992). https://www.nature.com/articles/360737a0 DOI: 10.1038/360737a0

evidence_locator

Abstract

experimental_model

RA-exposed preheadfold transgenic mouse embryos; lacZ and anatomy.

exposure

Experimental excess RA exposure

limitations

Timing-specific teratogenic experiment, not ordinary dietary intake.

nutrient_topic

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

organism

Mus musculus

plain_language

Excess RA can shift where an embryonic patterning gene is active.

primary_references

[va-marshall-1992] Retinoic acid alters hindbrain Hox code and induces transformation of rhombomeres 2/3 into a 4/5 identity (1992). https://www.nature.com/articles/360737a0 DOI: 10.1038/360737a0

tissue_or_cell_type

Preheadfold embryos/hindbrain

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1422–1433

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · RA-exposed preheadfold transgenic mouse embryos; lacZ and anatomy. · source_derived_draft · unverified_draft

### va-sig-excess-ra-hox-pattern Preheadfold RA exposure altered segmental Hoxb1 reporter expression in mouse hindbrain. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Excess RA can shift where an embryonic patterning gene is active. organism: Mus musculus tissue_or_cell_type: Preheadfold embryos/hindbrain experimental_model: RA-exposed preheadfold transgenic mouse embryos; lacZ and anatomy. limitations: Timing-specific teratogenic experiment, not ordinary dietary intake. evidence_locator: Abstract exposure: Experimental excess RA exposure [va-marshall-1992] Retinoic acid alters hindbrain Hox code and induces transformation of rhombomeres 2/3 into a 4/5 identity (1992). https://www.nature.com/articles/360737a0 DOI: 10.1038/360737a0

evidence_locator

Abstract

experimental_model

Mouse Hoxb1 enhancer transgenes; homologous chicken and pufferfish elements.

exposure

Enhancer transgenes and RA exposure

limitations

Enhancer behavior is not a maternal serum-retinol threshold.

nutrient_topic

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

organism

Mus musculus; comparative chicken/pufferfish enhancer sequences

plain_language

Embryonic RA signaling connects to a spatial developmental gene program.

primary_references

[va-marshall-1994] A conserved retinoic acid response element required for early expression of the homeobox gene Hoxb-1 (1994). https://www.nature.com/articles/370567a0 DOI: 10.1038/370567a0

tissue_or_cell_type

Early embryonic neuroectoderm

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1396–1407

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Mouse Hoxb1 enhancer transgenes; homologous chicken and pufferfish elements. · source_derived_draft · unverified_draft

### va-sig-hoxb1-ra-enhancer A conserved Hoxb1 enhancer containing a RARE mediated RA responsiveness and early neuroectodermal expression. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Embryonic RA signaling connects to a spatial developmental gene program. organism: Mus musculus; comparative chicken/pufferfish enhancer sequences tissue_or_cell_type: Early embryonic neuroectoderm experimental_model: Mouse Hoxb1 enhancer transgenes; homologous chicken and pufferfish elements. limitations: Enhancer behavior is not a maternal serum-retinol threshold. evidence_locator: Abstract exposure: Enhancer transgenes and RA exposure [va-marshall-1994] A conserved retinoic acid response element required for early expression of the homeobox gene Hoxb-1 (1994). https://www.nature.com/articles/370567a0 DOI: 10.1038/370567a0

evidence_locator

Abstract

experimental_model

Biochemical interactions and engineered cellular transcription reporters.

exposure

Ligand addition

limitations

Cofactor exchange varies by promoter and cell.

nutrient_topic

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

organism

Biochemical receptor system

plain_language

Ligand binding can release a transcriptional brake.

primary_references

[va-chen-1995] A transcriptional co-repressor that interacts with nuclear hormone receptors (1995). https://pubmed.ncbi.nlm.nih.gov/7566127/ DOI: 10.1038/377454a0

tissue_or_cell_type

Receptor complexes

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1149–1160

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Biochemical interactions and engineered cellular transcription reporters. · source_derived_draft · unverified_draft

### va-sig-ligand-smrt-release Ligand destabilized SMRT association with retinoid receptor complexes, including DNA-bound receptors. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Ligand binding can release a transcriptional brake. organism: Biochemical receptor system tissue_or_cell_type: Receptor complexes experimental_model: Biochemical interactions and engineered cellular transcription reporters. limitations: Cofactor exchange varies by promoter and cell. evidence_locator: Abstract exposure: Ligand addition [va-chen-1995] A transcriptional co-repressor that interacts with nuclear hormone receptors (1995). https://pubmed.ncbi.nlm.nih.gov/7566127/ DOI: 10.1038/377454a0

availability_state

nutrient_deficiency Imported condition classification; unverified.

evidence_locator

Abstract

experimental_model

Human normal tracheobronchial epithelial air-liquid interface cultures.

exposure

RA withdrawal

limitations

Does not demonstrate airway infection protection.

nutrient_topic

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

organism

Homo sapiens

plain_language

RA availability helps maintain the secretory phenotype in cultured airway cells.

primary_references

[va-yoon-1997] Regulation of the secretory phenotype of human airway epithelium by retinoic acid, triiodothyronine, and extracellular matrix (1997). https://pubmed.ncbi.nlm.nih.gov/9191474/ DOI: 10.1165/ajrcmb.16.6.9191474

tissue_or_cell_type

Normal tracheobronchial epithelial air-liquid interface culture

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1383–1394

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human normal tracheobronchial epithelial air-liquid interface cultures. · source_derived_draft · unverified_draft

### va-sig-ra-airway-secretion Removing RA from airway epithelial culture medium sharply reduced mucin secretion. Condition category: nutrient_deficiency nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: RA availability helps maintain the secretory phenotype in cultured airway cells. organism: Homo sapiens tissue_or_cell_type: Normal tracheobronchial epithelial air-liquid interface culture experimental_model: Human normal tracheobronchial epithelial air-liquid interface cultures. limitations: Does not demonstrate airway infection protection. evidence_locator: Abstract exposure: RA withdrawal [va-yoon-1997] Regulation of the secretory phenotype of human airway epithelium by retinoic acid, triiodothyronine, and extracellular matrix (1997). https://pubmed.ncbi.nlm.nih.gov/9191474/ DOI: 10.1165/ajrcmb.16.6.9191474

evidence_locator

Abstract

experimental_model

Mouse activated T cells, gut dendritic cells and vitamin A-deficient mice.

exposure

Added RA

limitations

Does not establish independent transcriptional induction of each subunit.

nutrient_topic

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

organism

Mus musculus

plain_language

RA helps activated T cells acquire an intestinal adhesion complex.

primary_references

[va-iwata-2004] Retinoic acid imprints gut-homing specificity on T cells (2004). https://pubmed.ncbi.nlm.nih.gov/15485630/ DOI: 10.1016/j.immuni.2004.08.011

tissue_or_cell_type

Activated T cells

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1188–1199

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Mouse activated T cells, gut dendritic cells and vitamin A-deficient mice. · source_derived_draft · unverified_draft

### va-sig-ra-alpha4beta7 RA during T-cell activation increased the alpha4beta7 gut-homing integrin. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: RA helps activated T cells acquire an intestinal adhesion complex. organism: Mus musculus tissue_or_cell_type: Activated T cells experimental_model: Mouse activated T cells, gut dendritic cells and vitamin A-deficient mice. limitations: Does not establish independent transcriptional induction of each subunit. evidence_locator: Abstract exposure: Added RA [va-iwata-2004] Retinoic acid imprints gut-homing specificity on T cells (2004). https://pubmed.ncbi.nlm.nih.gov/15485630/ DOI: 10.1016/j.immuni.2004.08.011

evidence_locator

Abstract

experimental_model

Mouse B-cell/dendritic-cell systems and vitamin A-deficient mice.

exposure

Gut dendritic-cell-derived RA

limitations

Gut tropism alone is not IgA secretion.

nutrient_topic

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

organism

Mus musculus

plain_language

RA helps route antibody-producing cell precursors to the intestine.

primary_references

[va-mora-2006] Generation of gut-homing IgA-secreting B cells by intestinal dendritic cells (2006). https://pubmed.ncbi.nlm.nih.gov/17110582/ DOI: 10.1126/science.1132742

tissue_or_cell_type

B-cell cultures

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1214–1225

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Mouse B-cell/dendritic-cell systems and vitamin A-deficient mice. · source_derived_draft · unverified_draft

### va-sig-ra-b-cell-homing Dendritic-cell-derived RA conferred gut tropism on activated B cells. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: RA helps route antibody-producing cell precursors to the intestine. organism: Mus musculus tissue_or_cell_type: B-cell cultures experimental_model: Mouse B-cell/dendritic-cell systems and vitamin A-deficient mice. limitations: Gut tropism alone is not IgA secretion. evidence_locator: Abstract exposure: Gut dendritic-cell-derived RA [va-mora-2006] Generation of gut-homing IgA-secreting B cells by intestinal dendritic cells (2006). https://pubmed.ncbi.nlm.nih.gov/17110582/ DOI: 10.1126/science.1132742

evidence_locator

Abstract

experimental_model

Mouse activated T cells, gut dendritic cells and vitamin A-deficient mice.

exposure

Added RA

limitations

Receptor expression is distinct from clinical infection protection.

nutrient_topic

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

organism

Mus musculus

plain_language

Activated cells acquire a receptor associated with gut entry.

primary_references

[va-iwata-2004] Retinoic acid imprints gut-homing specificity on T cells (2004). https://pubmed.ncbi.nlm.nih.gov/15485630/ DOI: 10.1016/j.immuni.2004.08.011

tissue_or_cell_type

Activated T cells

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1175–1186

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Mouse activated T cells, gut dendritic cells and vitamin A-deficient mice. · source_derived_draft · unverified_draft

### va-sig-ra-ccr9 RA during mouse T-cell activation increased CCR9 expression. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Activated cells acquire a receptor associated with gut entry. organism: Mus musculus tissue_or_cell_type: Activated T cells experimental_model: Mouse activated T cells, gut dendritic cells and vitamin A-deficient mice. limitations: Receptor expression is distinct from clinical infection protection. evidence_locator: Abstract exposure: Added RA [va-iwata-2004] Retinoic acid imprints gut-homing specificity on T cells (2004). https://pubmed.ncbi.nlm.nih.gov/15485630/ DOI: 10.1016/j.immuni.2004.08.011

evidence_locator

Abstract

experimental_model

Mouse B-cell/dendritic-cell systems and vitamin A-deficient mice.

exposure

RA with IL-6 or IL-5

limitations

Cannot generalize to every IgA-switching pathway.

nutrient_topic

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

organism

Mus musculus

plain_language

IgA output required additional immune signals in this experiment.

primary_references

[va-mora-2006] Generation of gut-homing IgA-secreting B cells by intestinal dendritic cells (2006). https://pubmed.ncbi.nlm.nih.gov/17110582/ DOI: 10.1126/science.1132742

tissue_or_cell_type

B-cell cultures

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1227–1238

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Mouse B-cell/dendritic-cell systems and vitamin A-deficient mice. · source_derived_draft · unverified_draft

### va-sig-ra-cytokine-iga RA alone was insufficient for IgA secretion but cooperated with IL-6 or IL-5 to induce it. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: IgA output required additional immune signals in this experiment. organism: Mus musculus tissue_or_cell_type: B-cell cultures experimental_model: Mouse B-cell/dendritic-cell systems and vitamin A-deficient mice. limitations: Cannot generalize to every IgA-switching pathway. evidence_locator: Abstract exposure: RA with IL-6 or IL-5 [va-mora-2006] Generation of gut-homing IgA-secreting B cells by intestinal dendritic cells (2006). https://pubmed.ncbi.nlm.nih.gov/17110582/ DOI: 10.1126/science.1132742

evidence_locator

Abstract and Figure 3

experimental_model

Mouse dendritic-cell/T-cell experiments and IL-15-rich intestinal models.

exposure

RA plus IL-15

limitations

No claim that dietary vitamin A causes coeliac disease.

nutrient_topic

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

organism

Mus musculus

plain_language

An inflammatory cytokine can redirect RA-associated immune signaling.

primary_references

[va-depaolo-2011] Co-adjuvant effects of retinoic acid and IL-15 induce inflammatory immunity to dietary antigens (2011). https://www.nature.com/articles/nature09849 DOI: 10.1038/nature09849

tissue_or_cell_type

Dendritic cells

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1292–1303

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Mouse dendritic-cell/T-cell experiments and IL-15-rich intestinal models. · source_derived_draft · unverified_draft

### va-sig-ra-il15-il12 RA with IL-15 promoted dendritic-cell IL-12p70 release. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: An inflammatory cytokine can redirect RA-associated immune signaling. organism: Mus musculus tissue_or_cell_type: Dendritic cells experimental_model: Mouse dendritic-cell/T-cell experiments and IL-15-rich intestinal models. limitations: No claim that dietary vitamin A causes coeliac disease. evidence_locator: Abstract and Figure 3 exposure: RA plus IL-15 [va-depaolo-2011] Co-adjuvant effects of retinoic acid and IL-15 induce inflammatory immunity to dietary antigens (2011). https://www.nature.com/articles/nature09849 DOI: 10.1038/nature09849

evidence_locator

Abstract and Figure 3

experimental_model

Mouse dendritic-cell/T-cell experiments and IL-15-rich intestinal models.

exposure

RA plus IL-15

limitations

Different context from isolated naive T-cell induction.

nutrient_topic

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

organism

Mus musculus

plain_language

RA participates in a proinflammatory response in this cytokine setting.

primary_references

[va-depaolo-2011] Co-adjuvant effects of retinoic acid and IL-15 induce inflammatory immunity to dietary antigens (2011). https://www.nature.com/articles/nature09849 DOI: 10.1038/nature09849

tissue_or_cell_type

Dendritic cells

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1305–1316

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Mouse dendritic-cell/T-cell experiments and IL-15-rich intestinal models. · source_derived_draft · unverified_draft

### va-sig-ra-il15-il23 RA with IL-15 promoted dendritic-cell IL-23 release. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: RA participates in a proinflammatory response in this cytokine setting. organism: Mus musculus tissue_or_cell_type: Dendritic cells experimental_model: Mouse dendritic-cell/T-cell experiments and IL-15-rich intestinal models. limitations: Different context from isolated naive T-cell induction. evidence_locator: Abstract and Figure 3 exposure: RA plus IL-15 [va-depaolo-2011] Co-adjuvant effects of retinoic acid and IL-15 induce inflammatory immunity to dietary antigens (2011). https://www.nature.com/articles/nature09849 DOI: 10.1038/nature09849

evidence_locator

Abstract

experimental_model

Mouse naive T-cell differentiation under TGF-beta and inflammatory cytokine conditions.

exposure

Added RA in TGF-beta-driven differentiation

limitations

Not an unconditional anti-inflammatory effect or human dietary outcome.

nutrient_topic

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

organism

Mus musculus

plain_language

RA can cooperate with TGF-beta to favor regulatory cells.

primary_references

[va-mucida-2007] Reciprocal TH17 and regulatory T cell differentiation mediated by retinoic acid (2007). https://pubmed.ncbi.nlm.nih.gov/17569825/ DOI: 10.1126/science.1145697

tissue_or_cell_type

Naive T-cell cultures

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1253–1264

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Mouse naive T-cell differentiation under TGF-beta and inflammatory cytokine conditions. · source_derived_draft · unverified_draft

### va-sig-ra-tgfb-foxp3 RA promoted regulatory T-cell differentiation under the tested TGF-beta-dependent conditions. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: RA can cooperate with TGF-beta to favor regulatory cells. organism: Mus musculus tissue_or_cell_type: Naive T-cell cultures experimental_model: Mouse naive T-cell differentiation under TGF-beta and inflammatory cytokine conditions. limitations: Not an unconditional anti-inflammatory effect or human dietary outcome. evidence_locator: Abstract exposure: Added RA in TGF-beta-driven differentiation [va-mucida-2007] Reciprocal TH17 and regulatory T cell differentiation mediated by retinoic acid (2007). https://pubmed.ncbi.nlm.nih.gov/17569825/ DOI: 10.1126/science.1145697

evidence_locator

Abstract

experimental_model

Mouse naive T-cell differentiation under TGF-beta and inflammatory cytokine conditions.

exposure

RA with IL-6/TGF-beta

limitations

New lineage induction differs from established intestinal Th17 effector function.

nutrient_topic

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

organism

Mus musculus

plain_language

The cytokine environment determines which T-cell differentiation program RA modifies.

primary_references

[va-mucida-2007] Reciprocal TH17 and regulatory T cell differentiation mediated by retinoic acid (2007). https://pubmed.ncbi.nlm.nih.gov/17569825/ DOI: 10.1126/science.1145697

tissue_or_cell_type

Naive T-cell cultures

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1266–1277

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Mouse naive T-cell differentiation under TGF-beta and inflammatory cytokine conditions. · source_derived_draft · unverified_draft

### va-sig-ra-th17-differentiation Added RA inhibited IL-6-driven Th17 induction in the tested TGF-beta context. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: The cytokine environment determines which T-cell differentiation program RA modifies. organism: Mus musculus tissue_or_cell_type: Naive T-cell cultures experimental_model: Mouse naive T-cell differentiation under TGF-beta and inflammatory cytokine conditions. limitations: New lineage induction differs from established intestinal Th17 effector function. evidence_locator: Abstract exposure: RA with IL-6/TGF-beta [va-mucida-2007] Reciprocal TH17 and regulatory T cell differentiation mediated by retinoic acid (2007). https://pubmed.ncbi.nlm.nih.gov/17569825/ DOI: 10.1126/science.1145697

evidence_locator

Abstract

experimental_model

Normal human tracheobronchial epithelial cultures with receptor-selective agonists/antagonists.

exposure

Receptor-selective agonists/antagonists

limitations

Transcript changes do not establish improved mucus clearance.

nutrient_topic

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

organism

Homo sapiens

plain_language

RAR signaling helps cultured airway cells adopt a mucus-producing program.

primary_references

[va-koo-1999] Role of retinoid receptors in the regulation of mucin gene expression by retinoic acid in human tracheobronchial epithelial cells (1999). https://pubmed.ncbi.nlm.nih.gov/10024510/ DOI: 10.1042/bj3380351

tissue_or_cell_type

Normal tracheobronchial epithelial cells

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1357–1368

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Normal human tracheobronchial epithelial cultures with receptor-selective agonists/antagonists. · source_derived_draft · unverified_draft

### va-sig-rara-airway-mucin RAR alpha-selective pharmacology supported RAR alpha-mediated induction of airway mucin transcripts, including MUC5AC. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: RAR signaling helps cultured airway cells adopt a mucus-producing program. organism: Homo sapiens tissue_or_cell_type: Normal tracheobronchial epithelial cells experimental_model: Normal human tracheobronchial epithelial cultures with receptor-selective agonists/antagonists. limitations: Transcript changes do not establish improved mucus clearance. evidence_locator: Abstract exposure: Receptor-selective agonists/antagonists [va-koo-1999] Role of retinoid receptors in the regulation of mucin gene expression by retinoic acid in human tracheobronchial epithelial cells (1999). https://pubmed.ncbi.nlm.nih.gov/10024510/ DOI: 10.1042/bj3380351

evidence_locator

Figure 2

experimental_model

Recombinant receptors, gel shifts, coimmunoprecipitation and CV-1 reporters.

exposure

Receptor coexpression/reconstitution

limitations

Synthetic response elements; not every genomic site.

nutrient_topic

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

organism

Recombinant receptors

plain_language

Two distinct receptor proteins assemble a DNA-binding complex.

primary_references

[va-kliewer-1992] Retinoid X receptor interacts with nuclear receptors in retinoic acid, thyroid hormone and vitamin D3 signalling (1992). https://pubmed.ncbi.nlm.nih.gov/1310351/ DOI: 10.1038/355446a0

tissue_or_cell_type

Cell-free DNA-binding assay

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1082–1093

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Recombinant receptors, gel shifts, coimmunoprecipitation and CV-1 reporters. · source_derived_draft · unverified_draft

### va-sig-rara-rxra-cooperative-binding RXRA associated with RARA and cooperatively bound retinoid response DNA. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Two distinct receptor proteins assemble a DNA-binding complex. organism: Recombinant receptors tissue_or_cell_type: Cell-free DNA-binding assay experimental_model: Recombinant receptors, gel shifts, coimmunoprecipitation and CV-1 reporters. limitations: Synthetic response elements; not every genomic site. evidence_locator: Figure 2 exposure: Receptor coexpression/reconstitution [va-kliewer-1992] Retinoid X receptor interacts with nuclear receptors in retinoic acid, thyroid hormone and vitamin D3 signalling (1992). https://pubmed.ncbi.nlm.nih.gov/1310351/ DOI: 10.1038/355446a0

availability_state

machinery_impairment Imported condition classification; unverified.

evidence_locator

Discussion and T-cell activation experiments

experimental_model

Vitamin A-insufficient and Rara-deficient mice; stimulated CD4 T cells.

exposure

Rara loss or RAR antagonism

limitations

Does not negate RA effects on Treg differentiation.

nutrient_topic

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

organism

Mus musculus

plain_language

Loss of receptor signaling can weaken effector-cell expansion.

primary_references

[va-hall-2011] Essential role for retinoic acid in the promotion of CD4(+) T cell effector responses via retinoic acid receptor alpha (2011). https://pmc.ncbi.nlm.nih.gov/articles/PMC3415227/ DOI: 10.1016/j.immuni.2011.03.003

tissue_or_cell_type

CD4 T cells

trigger_kind

machinery_impairment Imported condition classification; unverified.

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1279–1290

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Vitamin A-insufficient and Rara-deficient mice; stimulated CD4 T cells. · source_derived_draft · unverified_draft

### va-sig-rara-t-cell-proliferation Rara-deficient or RAR-antagonized T cells proliferated less efficiently after stimulation. Condition category: machinery_impairment nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Loss of receptor signaling can weaken effector-cell expansion. organism: Mus musculus tissue_or_cell_type: CD4 T cells experimental_model: Vitamin A-insufficient and Rara-deficient mice; stimulated CD4 T cells. limitations: Does not negate RA effects on Treg differentiation. evidence_locator: Discussion and T-cell activation experiments exposure: Rara loss or RAR antagonism [va-hall-2011] Essential role for retinoic acid in the promotion of CD4(+) T cell effector responses via retinoic acid receptor alpha (2011). https://pmc.ncbi.nlm.nih.gov/articles/PMC3415227/ DOI: 10.1016/j.immuni.2011.03.003

evidence_locator

Abstract

experimental_model

Human TIF2 cloning; in vitro receptor-domain interactions and cellular reporters.

exposure

Agonist versus control; AF-2 mutants

limitations

Domain assays do not resolve every endogenous chromatin complex.

nutrient_topic

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

organism

Human TIF2 and engineered receptor domains

plain_language

An activated receptor gains a binding surface for a transcriptional coactivator.

primary_references

[va-voegel-1996] TIF2, a 160 kDa transcriptional mediator for the ligand-dependent activation function AF-2 of nuclear receptors (1996). https://pubmed.ncbi.nlm.nih.gov/8670870/ DOI: 10.1002/j.1460-2075.1996.tb00736.x

tissue_or_cell_type

Cell-free and cellular interaction assays

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1162–1173

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human TIF2 cloning; in vitro receptor-domain interactions and cellular reporters. · source_derived_draft · unverified_draft

### va-sig-rara-tif2-recruitment The agonist-bound RAR ligand-binding domain interacted with TIF2 in an AF-2-dependent manner. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: An activated receptor gains a binding surface for a transcriptional coactivator. organism: Human TIF2 and engineered receptor domains tissue_or_cell_type: Cell-free and cellular interaction assays experimental_model: Human TIF2 cloning; in vitro receptor-domain interactions and cellular reporters. limitations: Domain assays do not resolve every endogenous chromatin complex. evidence_locator: Abstract exposure: Agonist versus control; AF-2 mutants [va-voegel-1996] TIF2, a 160 kDa transcriptional mediator for the ligand-dependent activation function AF-2 of nuclear receptors (1996). https://pubmed.ncbi.nlm.nih.gov/8670870/ DOI: 10.1002/j.1460-2075.1996.tb00736.x

evidence_locator

Figure 2; Methods

experimental_model

Mouse MODE-K cells and intestinal epithelial Rarb deletion.

exposure

100 nM retinol plus 100 ng/mL LPS for 24 h

limitations

Direct binding to Saa1/Saa2 was predicted, not demonstrated here.

nutrient_topic

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

organism

Mus musculus

plain_language

Epithelial retinoid sensing directly controls this mouse immune gene.

primary_references

[va-gattu-2019] Epithelial retinoic acid receptor beta regulates serum amyloid A expression and vitamin A-dependent intestinal immunity (2019). https://pmc.ncbi.nlm.nih.gov/articles/PMC6561173/ DOI: 10.1073/pnas.1812069116

tissue_or_cell_type

MODE-K intestinal epithelial cells

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1318–1329

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Mouse MODE-K cells and intestinal epithelial Rarb deletion. · source_derived_draft · unverified_draft

### va-sig-rarb-saa3-promoter RAR beta occupied the mouse Saa3 promoter; mutation of RARE -224 abolished reporter activity. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Epithelial retinoid sensing directly controls this mouse immune gene. organism: Mus musculus tissue_or_cell_type: MODE-K intestinal epithelial cells experimental_model: Mouse MODE-K cells and intestinal epithelial Rarb deletion. limitations: Direct binding to Saa1/Saa2 was predicted, not demonstrated here. evidence_locator: Figure 2; Methods exposure: 100 nM retinol plus 100 ng/mL LPS for 24 h [va-gattu-2019] Epithelial retinoic acid receptor beta regulates serum amyloid A expression and vitamin A-dependent intestinal immunity (2019). https://pmc.ncbi.nlm.nih.gov/articles/PMC6561173/ DOI: 10.1073/pnas.1812069116

availability_state

machinery_impairment Imported condition classification; unverified.

evidence_locator

Figure 4A-D

experimental_model

Mouse MODE-K cells and intestinal epithelial Rarb deletion.

exposure

Epithelial Rarb deletion

limitations

Does not establish a complete retinol-transfer chain.

nutrient_topic

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

organism

Mus musculus

plain_language

A receptor in epithelial cells helps neighboring immune cells function.

primary_references

[va-gattu-2019] Epithelial retinoic acid receptor beta regulates serum amyloid A expression and vitamin A-dependent intestinal immunity (2019). https://pmc.ncbi.nlm.nih.gov/articles/PMC6561173/ DOI: 10.1073/pnas.1812069116

tissue_or_cell_type

Intestinal lamina propria

trigger_kind

machinery_impairment Imported condition classification; unverified.

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1331–1342

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Mouse MODE-K cells and intestinal epithelial Rarb deletion. · source_derived_draft · unverified_draft

### va-sig-rarb-th17-effector Epithelial Rarb deletion reduced intestinal Th17 IL-17A production without reducing overall Th17 frequency. Condition category: machinery_impairment nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: A receptor in epithelial cells helps neighboring immune cells function. organism: Mus musculus tissue_or_cell_type: Intestinal lamina propria experimental_model: Mouse MODE-K cells and intestinal epithelial Rarb deletion. limitations: Does not establish a complete retinol-transfer chain. evidence_locator: Figure 4A-D exposure: Epithelial Rarb deletion [va-gattu-2019] Epithelial retinoic acid receptor beta regulates serum amyloid A expression and vitamin A-dependent intestinal immunity (2019). https://pmc.ncbi.nlm.nih.gov/articles/PMC6561173/ DOI: 10.1073/pnas.1812069116

evidence_locator

Abstract

experimental_model

Normal human tracheobronchial epithelial cultures with receptor-selective agonists/antagonists.

exposure

Selective receptor agonists

limitations

No inference that 9-cis RA improves airway disease.

nutrient_topic

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

organism

Homo sapiens

plain_language

Both partners can cooperate, with RAR activation required in this assay.

primary_references

[va-koo-1999] Role of retinoid receptors in the regulation of mucin gene expression by retinoic acid in human tracheobronchial epithelial cells (1999). https://pubmed.ncbi.nlm.nih.gov/10024510/ DOI: 10.1042/bj3380351

tissue_or_cell_type

Normal tracheobronchial epithelial cells

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1370–1381

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Normal human tracheobronchial epithelial cultures with receptor-selective agonists/antagonists. · source_derived_draft · unverified_draft

### va-sig-rxr-airway-cooperation An RXR-selective agonist alone failed to induce mucin transcripts but enhanced a suboptimal RAR agonist response. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Both partners can cooperate, with RAR activation required in this assay. organism: Homo sapiens tissue_or_cell_type: Normal tracheobronchial epithelial cells experimental_model: Normal human tracheobronchial epithelial cultures with receptor-selective agonists/antagonists. limitations: No inference that 9-cis RA improves airway disease. evidence_locator: Abstract exposure: Selective receptor agonists [va-koo-1999] Role of retinoid receptors in the regulation of mucin gene expression by retinoic acid in human tracheobronchial epithelial cells (1999). https://pubmed.ncbi.nlm.nih.gov/10024510/ DOI: 10.1042/bj3380351

evidence_locator

Abstract

experimental_model

Receptor interaction, DNA binding and transfection experiments.

exposure

Receptor cotransfection and RA

limitations

Reporter-system dependence; no nutrient dose response.

nutrient_topic

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

organism

Engineered cellular receptor system

plain_language

RXRA can assist RAR signaling without equivalent activation of both partners.

primary_references

[va-zhang-1992] Retinoid X receptor is an auxiliary protein for thyroid hormone and retinoic acid receptors (1992). https://pubmed.ncbi.nlm.nih.gov/1310350/ DOI: 10.1038/355441a0

tissue_or_cell_type

Transfection reporters

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1123–1134

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Receptor interaction, DNA binding and transfection experiments. · source_derived_draft · unverified_draft

### va-sig-rxra-rar-transactivation RXRA enhanced RAR-mediated transcription at RA concentrations insufficient to substantially activate RXRA itself. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: RXRA can assist RAR signaling without equivalent activation of both partners. organism: Engineered cellular receptor system tissue_or_cell_type: Transfection reporters experimental_model: Receptor interaction, DNA binding and transfection experiments. limitations: Reporter-system dependence; no nutrient dose response. evidence_locator: Abstract exposure: Receptor cotransfection and RA [va-zhang-1992] Retinoid X receptor is an auxiliary protein for thyroid hormone and retinoic acid receptors (1992). https://pubmed.ncbi.nlm.nih.gov/1310350/ DOI: 10.1038/355441a0

cross_nutrient

Vitamin A-iodine: shared receptor machinery for an iodine-containing hormone; not evidence of iodine repletion.

evidence_locator

Figure 3

experimental_model

Recombinant receptors, gel shifts, coimmunoprecipitation and CV-1 reporters.

exposure

Reconstituted TR beta/RXRA

limitations

No iodine nutritional manipulation.

nutrient_topic

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

organism

Recombinant receptors

plain_language

A receptor used by retinoids also supports thyroid-hormone DNA recognition.

primary_references

[va-kliewer-1992] Retinoid X receptor interacts with nuclear receptors in retinoic acid, thyroid hormone and vitamin D3 signalling (1992). https://pubmed.ncbi.nlm.nih.gov/1310351/ DOI: 10.1038/355446a0

tissue_or_cell_type

Cell-free DNA-binding assay

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1109–1121

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Recombinant receptors, gel shifts, coimmunoprecipitation and CV-1 reporters. · source_derived_draft · unverified_draft

### va-sig-rxra-thrb-partnership RXRA complexed with TR beta and enhanced thyroid-response-element binding. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: A receptor used by retinoids also supports thyroid-hormone DNA recognition. organism: Recombinant receptors tissue_or_cell_type: Cell-free DNA-binding assay experimental_model: Recombinant receptors, gel shifts, coimmunoprecipitation and CV-1 reporters. limitations: No iodine nutritional manipulation. evidence_locator: Figure 3 cross_nutrient: Vitamin A-iodine: shared receptor machinery for an iodine-containing hormone; not evidence of iodine repletion. exposure: Reconstituted TR beta/RXRA [va-kliewer-1992] Retinoid X receptor interacts with nuclear receptors in retinoic acid, thyroid hormone and vitamin D3 signalling (1992). https://pubmed.ncbi.nlm.nih.gov/1310351/ DOI: 10.1038/355446a0

cross_nutrient

Vitamin A-vitamin D: shared receptor partner; no supplementation or deficiency rescue tested.

evidence_locator

Figure 3

experimental_model

Recombinant receptors, gel shifts, coimmunoprecipitation and CV-1 reporters.

exposure

Reconstituted VDR/RXRA

limitations

Does not prove vitamin A intake enhances calcium absorption.

nutrient_topic

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

organism

Recombinant receptors

plain_language

Vitamin D signaling shares RXRA receptor machinery with retinoid pathways.

primary_references

[va-kliewer-1992] Retinoid X receptor interacts with nuclear receptors in retinoic acid, thyroid hormone and vitamin D3 signalling (1992). https://pubmed.ncbi.nlm.nih.gov/1310351/ DOI: 10.1038/355446a0

tissue_or_cell_type

Cell-free DNA-binding assay

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1095–1107

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Recombinant receptors, gel shifts, coimmunoprecipitation and CV-1 reporters. · source_derived_draft · unverified_draft

### va-sig-rxra-vdr-partnership RXRA formed a VDR complex and enhanced binding to the osteopontin vitamin D response element. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Vitamin D signaling shares RXRA receptor machinery with retinoid pathways. organism: Recombinant receptors tissue_or_cell_type: Cell-free DNA-binding assay experimental_model: Recombinant receptors, gel shifts, coimmunoprecipitation and CV-1 reporters. limitations: Does not prove vitamin A intake enhances calcium absorption. evidence_locator: Figure 3 cross_nutrient: Vitamin A-vitamin D: shared receptor partner; no supplementation or deficiency rescue tested. exposure: Reconstituted VDR/RXRA [va-kliewer-1992] Retinoid X receptor interacts with nuclear receptors in retinoic acid, thyroid hormone and vitamin D3 signalling (1992). https://pubmed.ncbi.nlm.nih.gov/1310351/ DOI: 10.1038/355446a0

availability_state

machinery_impairment Imported condition classification; unverified.

evidence_locator

Figure 4E

experimental_model

Mouse MODE-K cells and intestinal epithelial Rarb deletion.

exposure

rSAA1 during 4-hour stimulation

limitations

Rescue does not establish delivery of retinol to Th17 cells.

nutrient_topic

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

organism

Mus musculus

plain_language

Adding an epithelial-associated mediator rescued the measured immune output.

primary_references

[va-gattu-2019] Epithelial retinoic acid receptor beta regulates serum amyloid A expression and vitamin A-dependent intestinal immunity (2019). https://pmc.ncbi.nlm.nih.gov/articles/PMC6561173/ DOI: 10.1073/pnas.1812069116

tissue_or_cell_type

Ex vivo intestinal lamina propria cells

trigger_kind

machinery_impairment Imported condition classification; unverified.

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1344–1355

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Mouse MODE-K cells and intestinal epithelial Rarb deletion. · source_derived_draft · unverified_draft

### va-sig-saa1-rescue-th17 Recombinant SAA1 restored impaired Th17 cytokine output in cultured lamina propria cells from epithelial Rarb mutants. Condition category: machinery_impairment nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Adding an epithelial-associated mediator rescued the measured immune output. organism: Mus musculus tissue_or_cell_type: Ex vivo intestinal lamina propria cells experimental_model: Mouse MODE-K cells and intestinal epithelial Rarb deletion. limitations: Rescue does not establish delivery of retinol to Th17 cells. evidence_locator: Figure 4E exposure: rSAA1 during 4-hour stimulation [va-gattu-2019] Epithelial retinoic acid receptor beta regulates serum amyloid A expression and vitamin A-dependent intestinal immunity (2019). https://pmc.ncbi.nlm.nih.gov/articles/PMC6561173/ DOI: 10.1073/pnas.1812069116

evidence_locator

Abstract

experimental_model

Biochemical interactions and engineered cellular transcription reporters.

exposure

Unliganded receptor and SMRT

limitations

Not a claim that all unliganded RAR targets are repressed.

nutrient_topic

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

organism

Biochemical and cellular reporter systems

plain_language

Corepressor proteins help keep selected receptor-controlled genes quiet.

primary_references

[va-chen-1995] A transcriptional co-repressor that interacts with nuclear hormone receptors (1995). https://pubmed.ncbi.nlm.nih.gov/7566127/ DOI: 10.1038/377454a0

tissue_or_cell_type

Receptor complexes

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1136–1147

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Biochemical interactions and engineered cellular transcription reporters. · source_derived_draft · unverified_draft

### va-sig-smrt-repression SMRT associated with retinoid receptors and mediated transcriptional silencing in engineered assays. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Corepressor proteins help keep selected receptor-controlled genes quiet. organism: Biochemical and cellular reporter systems tissue_or_cell_type: Receptor complexes experimental_model: Biochemical interactions and engineered cellular transcription reporters. limitations: Not a claim that all unliganded RAR targets are repressed. evidence_locator: Abstract exposure: Unliganded receptor and SMRT [va-chen-1995] A transcriptional co-repressor that interacts with nuclear hormone receptors (1995). https://pubmed.ncbi.nlm.nih.gov/7566127/ DOI: 10.1038/377454a0

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

Zinc/vitamin A -> dark-adaptation response.

experimental_model

Three-week zinc randomization, existing vitamin A allocation.

limitations

Not a universal zinc requirement; relative estimate had a wide confidence interval.

nutrient_topic

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

organism

Homo sapiens

plain_language

An additional shortage may limit the response, but this result was subgroup-specific.

primary_references

[va-christian2001] Zinc supplementation might potentiate the effect of vitamin A in restoring night vision in pregnant Nepalese women (2001). https://pubmed.ncbi.nlm.nih.gov/11382658/ DOI: 10.1093/ajcn/73.6.1045

tissue_or_cell_type

Human visual function

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1507–1517

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Three-week zinc randomization, existing vitamin A allocation. · source_derived_draft · unverified_draft

### va-zinc-night-vision-subgroup In women with low initial zinc, vitamin A plus zinc improved night-vision recovery versus double placebo; zinc alone did not. Condition category: nutrient_deficiency nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: An additional shortage may limit the response, but this result was subgroup-specific. organism: Homo sapiens tissue_or_cell_type: Human visual function experimental_model: Three-week zinc randomization, existing vitamin A allocation. limitations: Not a universal zinc requirement; relative estimate had a wide confidence interval. cross_nutrient: Zinc/vitamin A -> dark-adaptation response. [va-christian2001] Zinc supplementation might potentiate the effect of vitamin A in restoring night vision in pregnant Nepalese women (2001). https://pubmed.ncbi.nlm.nih.gov/11382658/ DOI: 10.1093/ajcn/73.6.1045

availability_state

machinery_impairment Imported condition classification; unverified.

cross_nutrient

true

experimental_model

Longitudinal treated cohort; 10 abetalipoproteinemia and 3 homozygous hypobetalipoproteinemia patients

exposure

Combined oral vitamins A and E; mean 11.7 years follow-up, range 4–20; exact doses unavailable in abstract.

limitations

No randomized A-only, E-only or untreated comparator. Residual retinal disease is compatible with partial benefit; it is not proof that supplementation has no effect.

nutrient_topic

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

organism

Homo sapiens

plain_language

Combined treatment did not fully prevent retinal abnormalities in every patient.

primary_references

[e-clin-retina2001] Long-term assessment of combined vitamin A and E treatment for the prevention of retinal degeneration in abetalipoproteinaemia and hypobetalipoproteinaemia patients. (2001). https://pubmed.ncbi.nlm.nih.gov/11767031/ DOI: 10.1038/eye.2001.167

tissue_or_cell_type

Retina

trigger_kind

machinery_impairment Imported condition classification; unverified.

Vitamin E: transport, membrane protection and nutrient interactions (2026-09-17) · lines 1466–1477

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Longitudinal treated cohort; 10 abetalipoproteinemia and 3 homozygous hypobetalipoproteinemia patients · source_derived_draft · unverified_draft

### e-clin-abetalipo-residual-retinopathy Despite combined vitamin A and E treatment, 11 of 13 ABL/HBL patients had subnormal mixed cone-rod electroretinogram amplitudes at long-term follow-up. Condition category: machinery_impairment nutrient_topic: Vitamin E research collection; topical membership is not evidence of a direct dietary effect. plain_language: Combined treatment did not fully prevent retinal abnormalities in every patient. organism: Homo sapiens tissue_or_cell_type: Retina experimental_model: Longitudinal treated cohort; 10 abetalipoproteinemia and 3 homozygous hypobetalipoproteinemia patients limitations: No randomized A-only, E-only or untreated comparator. Residual retinal disease is compatible with partial benefit; it is not proof that supplementation has no effect. exposure: Combined oral vitamins A and E; mean 11.7 years follow-up, range 4–20; exact doses unavailable in abstract. cross_nutrient: true [e-clin-retina2001] Long-term assessment of combined vitamin A and E treatment for the prevention of retinal degeneration in abetalipoproteinaemia and hypobetalipoproteinaemia patients. (2001). https://pubmed.ncbi.nlm.nih.gov/11767031/ DOI: 10.1038/eye.2001.167

availability_state

machinery_impairment Imported condition classification; unverified.

evidence_span

{"source_cache": "artifacts/alcohol-research/10358022.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "c1e4e6f0703d814d36609e71a38be53f7c36bebcfdcd3a60c52ea49625369305", "start_char": 0, "end_char": 1272, "text_sha256": "c1e4e6f0703d814d36609e71a38be53f7c36bebcfdcd3a60c52ea49625369305"}

experimental_model

Adh1, Adh3 and Adh4 null mutant mice with ethanol, formaldehyde and retinol challenges

exposure

Intoxicating ethanol dose, formaldehyde LD50, and retinol administration

limitations

A clean three-gene dissection showing which enzyme does which job. It is a mouse gene family that does not map one-to-one onto the human one.

nutrient_topic

Alcohol research collection; topical membership is not evidence of a direct clinical effect, and ethanol is recorded separately from the acetaldehyde it becomes. · Ethanol

organism

Mouse

plain_language

The same enzymes that clear alcohol also turn vitamin A into its signalling form.

primary_references

[alcohol-p10358022] Metabolic deficiencies in alcohol dehydrogenase Adh1, Adh3, and Adh4 null mutant mice. Overlapping roles of Adh1 and Adh4 in ethanol clearance and metabolism of retinol to retinoic acid. (1999). https://pubmed.ncbi.nlm.nih.gov/10358022/ DOI: 10.1074/jbc.274.24.16796

tissue_or_cell_type

Liver and embryo

trigger_kind

machinery_impairment Imported condition classification; unverified.

Alcohol: ethanol clearance, acetaldehyde, the channels it binds, organ injury and nutrient collisions (2026-09-21) · lines 241–252

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Adh1, Adh3 and Adh4 null mutant mice with ethanol, formaldehyde and retinol challenges · source_derived_draft · unverified_draft

### alcohol-adh-retinoic-acid Retinoic acid production following retinol administration was reduced 8.5-fold in Adh4-null mice and 4.8-fold in Adh1-null mice, showing overlapping roles for Adh1 and Adh4 in both ethanol and retinol metabolism. Condition category: machinery_impairment nutrient_topic: Alcohol research collection; topical membership is not evidence of a direct clinical effect, and ethanol is recorded separately from the acetaldehyde it becomes. plain_language: The same enzymes that clear alcohol also turn vitamin A into its signalling form. organism: Mouse tissue_or_cell_type: Liver and embryo experimental_model: Adh1, Adh3 and Adh4 null mutant mice with ethanol, formaldehyde and retinol challenges limitations: A clean three-gene dissection showing which enzyme does which job. It is a mouse gene family that does not map one-to-one onto the human one. exposure: Intoxicating ethanol dose, formaldehyde LD50, and retinol administration evidence_span: {"source_cache": "artifacts/alcohol-research/10358022.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "c1e4e6f0703d814d36609e71a38be53f7c36bebcfdcd3a60c52ea49625369305", "start_char": 0, "end_char": 1272, "text_sha256": "c1e4e6f0703d814d36609e71a38be53f7c36bebcfdcd3a60c52ea49625369305"} [alcohol-p10358022] Metabolic deficiencies in alcohol dehydrogenase Adh1, Adh3, and Adh4 null mutant mice. Overlapping roles of Adh1 and Adh4 in ethanol clearance and metabolism of retinol to retinoic acid. (1999). https://pubmed.ncbi.nlm.nih.gov/10358022/ DOI: 10.1074/jbc.274.24.16796