Meta Information
ID:vitamin-a
Name:
Schema Version:2.4_uniform_evidence_2026_06_18
Created
2026-05-21T22:30:00Z
Model
phase-a-upgrade-claude-sonnet-4.6
Interactions
Target id:
/condition/pregnancy
Target name:
Pregnancy
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
High doses of preformed Vitamin A (retinol) are teratogenic and can cause severe birth defects by interfering with fetal development.
Actionable advice:
Supplemental Vitamin A (retinol/retinyl esters) above the recommended dietary allowance should be avoided during pregnancy unless medically prescribed.
Validation status:
anecdotal
Evidence tier:
tier_d
Evidence basis:
anecdotal_summary
Evidence anchors:
Exact phrase from label:
If you take too much preformed vitamin A while pregnant, it can cause birth defects in your baby, including abnormal eyes, skull, lungs, and heart.
Label source:
Anecdotal: NIH ODS
Action type:
avoid
Target id:
/class/retinoids
Target name:
Systemic Retinoids (e.g., Isotretinoin, Acitretin) (Concurrent)
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Concurrent use of Vitamin A supplements with prescription retinoid drugs leads to additive effects and a high risk of Vitamin A toxicity (hypervitaminosis A).
Actionable advice:
Vitamin A supplements should not be taken while using oral prescription retinoids like isotretinoin.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Toxicity has been associated with abuse of vitamin A supplements and with diets extremely high in preformed vitamin A.
Label source:
PubMed: Evaluation of vitamin A toxicity. (PMID 2197848)
Action type:
avoid
Target id:
/class/hepatotoxic-agents
Target name:
Liver-toxic Medications or Substances
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
High doses of Vitamin A can be toxic to the liver. Combining it with other substances known to cause liver damage (e.g., heavy alcohol use, high-dose acetaminophen) significantly increases the risk of hepatotoxicity.
Actionable advice:
High-dose Vitamin A supplementation should be avoided by those who consume alcohol heavily or take other potentially liver-toxic medications.
Validation status:
validated_via_pubmed
Evidence tier:
tier_b
Evidence basis:
pubmed_abstract_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
It is, however, complicated by the intrinsic hepatotoxicity of retinol, which is potentiated by concomitant alcohol consumption.
Label source:
PubMed: The American journal of clinical nutrition (1999)
Source url:
Exact phrase from label:
This study was designed to elucidate the mechanism of retinol's potentiation of acetaminophen-induced hepatotoxicity.
Label source:
PubMed: Toxicology and applied pharmacology (2001)
Source url:
Exact phrase from label:
The lowest reported intakes causing toxicity have occurred in persons with liver function compromised by drugs, viral hepatitis, or protein-energy malnutrition.
Label source:
PubMed: The American journal of clinical nutrition (1990)
Action type:
avoid
Target id:
/condition/hepatic-impairment
Target name:
Hepatic Impairment
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
A damaged liver cannot properly store and metabolize Vitamin A, which dramatically increases the risk of toxicity even at standard doses.
Actionable advice:
Vitamin A supplementation should be avoided with liver disease, unless under strict medical supervision.
Validation status:
validated_via_pubmed
Evidence tier:
tier_b
Evidence basis:
pubmed_abstract_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
The lowest reported intakes causing toxicity have occurred in persons with liver function compromised by drugs, viral hepatitis, or protein-energy malnutrition.
Label source:
PubMed: The American journal of clinical nutrition (1990)
Source url:
Exact phrase from label:
Vitamin A malnutrition in cirrhotics may be caused by poor diet, malabsorption, decreased hepatic vitamin A uptake, and decreased hepatic storage capacity for vitamin A.
Label source:
PubMed: The American journal of clinical nutrition (1980)
Source url:
Exact phrase from label:
Liver diseases, in particular those leading to fibrosis and cirrhosis, are associated with impaired vitamin A homeostasis and may lead to vitamin A deficiency.
Label source:
PubMed: Nutrients (2017)
Action type:
avoid
Target id:
/dietary/high-fat-meal
Target name:
Meal Containing Dietary Fat
Severity:
major
Interaction type:
requirement
Nature:
temporal
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Vitamin A is a fat-soluble vitamin, and its absorption from the intestine is dependent on the presence of dietary fats and bile acids.
Actionable advice:
Vitamin A supplements should be taken with a meal that contains some fat or oil to ensure proper absorption.
Validation status:
validated_via_pubmed
Evidence tier:
tier_b
Evidence basis:
pubmed_abstract_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Efficient absorption of dietary vitamin A depends on the fat-solubilizing properties of bile acids.
Label source:
PubMed: Biochimica et biophysica acta. Molecular and cell biology of lipids (2017)
Source url:
Exact phrase from label:
The fat-soluble vitamins are vitamins A, D, E, and K. Each vitamin has unique characteristics and contributes to the overall health of an individual. These vitamins have complex absorption, metabolism, and distribution elements that provide protection to the cells in the body as well as many organs.
Label source:
PubMed: The Nursing clinics of North America (2021)
Source url:
Exact phrase from label:
Dietary fat facilitates the utilization of carotenoids and, based on serum beta-carotene or retinol responses following ingestion of meals containing carotene and fat sources, it has been reported that the amount of fat required in a meal may be minimal (approximately 3-5 g).
Label source:
PubMed: Nutrition reviews (2002)
Action type:
informational_none
Target id:
/class/anticoagulants-antiplatelets
Target name:
Anticoagulants and Antiplatelets
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
High doses of Vitamin A may interfere with Vitamin K absorption or function, potentially increasing the blood-thinning effect of these medications and raising the risk of bleeding.
Actionable advice:
It is important to talk to a doctor before taking high-dose Vitamin A while on blood-thinning medication like warfarin.
Validation status:
validated_via_pubmed
Evidence tier:
tier_b
Evidence basis:
pubmed_abstract_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Vitamin A also significantly decreased the uptake of the other FSVs but, conversely, its uptake was not impaired by vitamins D and K and even promoted by vitamin E.
Label source:
PubMed: Food chemistry (2015)
Source url:
Exact phrase from label:
all-trans retinoic acid (a vitamin A derivative), two MAP4K inhibitors, and the chemotherapeutic drug Dasatinib. Conversely, the endogenous anticoagulant Protein S (PS) and the matricellular protein secreted modular calcium-binding protein 1 (SMOC1) both enhance clot retraction.
Label source:
PubMed: International journal of molecular sciences (2023)
Source url:
Exact phrase from label:
The regulation of the activation of the vitamin K-vitamin K-epoxide cycle by drugs and nutrients appears to be the key to controlling the synthesis of vitamin K-dependent proteins, eight of which are involved in blood coagulation.
Label source:
PubMed: Annual review of nutrition (1984)
Action type:
informational_none
Target id:
/class/bile-acid-sequestrants
Target name:
Bile Acid Sequestrants
Severity:
moderate
Interaction type:
diminishing
Nature:
temporal
Temporal spacing:
Hours before target:
4
Hours after target:
1
Description:
Medications like cholestyramine and colestipol bind to bile acids in the gut, which can significantly reduce the absorption of fat-soluble vitamins, including Vitamin A.
Actionable advice:
Vitamin A is best taken at least 1 hour before or 4-6 hours after a bile acid sequestrant.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
The bile-acid sequestrants--cholestyramine and colestipol--primarily decrease LDL cholesterol by binding bile acids, thereby decreasing intrahepatic cholesterol, and by increasing the activity of LDL receptors.
Label source:
PubMed: Currently available hypolipidaemic drugs and future therapeutic developments. (PMID 8593127)
Action type:
separate
Target id:
/intervention/orlistat
Target name:
Orlistat (Fat Absorption Inhibitor)
Severity:
moderate
Interaction type:
diminishing
Nature:
temporal
Temporal spacing:
Hours before target:
2
Hours after target:
2
Description:
Orlistat blocks the absorption of dietary fat, which consequently prevents the absorption of fat-soluble vitamins like Vitamin A taken at the same time.
Actionable advice:
Vitamin A supplements are best taken at least 2 hours before or 2 hours after a dose of orlistat.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
An open-label, placebo-controlled, randomized, two-way crossover study was performed in 12 healthy volunteers (between 20 and 44 years of age) to assess the effect of orlistat, a gastrointestinal lipase inhibitor that reduces dietary fat absorption and is being developed for weight control in obesity, on the absorption of vitamins A and E.
Label source:
PubMed: The effect of orlistat, an inhibitor of dietary fat absorption, on the absorption of vitamins A and E in healthy volunteers. (PMID 8844448)
Action type:
separate
Target id:
/condition/renal-impairment
Target name:
Renal Impairment
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Patients with chronic kidney disease have altered Vitamin A metabolism and transport, leading to elevated blood levels and an increased risk of toxicity.
Actionable advice:
Vitamin A supplements are best used with caution and under medical guidance in the presence of kidney disease.
Validation status:
validated_via_pubmed
Evidence tier:
tier_b
Evidence basis:
pubmed_abstract_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
RBP4 and retinol levels were increased approximately twofold in patients with CKD, with a negative correlation between plasma retinol and eGFR (p = 0.006) and plasma RBP4 and eGFR (p = 0.0007).
Label source:
PubMed: Clinical and translational science (2016)
Source url:
Exact phrase from label:
Plasma RBP levels are low in patients with liver disease and are high in patients with chronic renal disease. These findings reflect the facts that RBP is produced in the liver and mainly catabolized in the kidneys.
Label source:
PubMed: Annals of the New York Academy of Sciences (1980)
Source url:
Exact phrase from label:
Serum vitamin A concentrations were measured in 38 patients undergoing haemodialysis, 24 of whom were taking multivitamin preparations containing vitamin A. Vitamin A concentrations were significantly higher in patients undergoing haemodialysis than in 28 normal controls (p less than 0.001).
Label source:
PubMed: British medical journal (Clinical research ed.) (1981)
Action type:
informational_none
Target id:
/intervention/zinc
Target name:
Zinc
Severity:
moderate
Interaction type:
synergistic
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Zinc is essential for synthesizing retinol-binding protein (RBP), which transports Vitamin A from the liver to the rest of the body. Zinc deficiency can impair Vitamin A utilization.
Actionable advice:
Adequate zinc intake or supplementation is a good idea to support proper Vitamin A metabolism and function.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Multiple micronutrient interventions demonstrated synergistic effects in reducing iron deficiency (RR 0.44, 95% CI 0.32-0.60) and vitamin A deficiency (RR 0.42, 95% CI 0.28-0.62).
Label source:
PubMed: The role of specific nutrients in preventing immune system and blood cell disorders: an umbrella review. (PMID 42256481)
Action type:
informational_none
Target id:
/biomarker/comprehensive-liver-function-panel
Target name:
Liver Function Tests (ALT, AST)
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Chronic high-dose intake of Vitamin A can be hepatotoxic, leading to elevated liver enzymes (ALT, AST) which are markers of liver stress or damage.
Actionable advice:
Periodically monitor liver function with blood tests if taking long-term, high-dose Vitamin A supplements.
Validation status:
validated_via_pubmed
Evidence tier:
tier_b
Evidence basis:
pubmed_abstract_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
A 62-yr-old white male presented with edema, protein malnutrition, and abnormal liver function. He had ingested from 40,000-50,000 IU of vitamin A per day for 7 yr.
Label source:
PubMed: Gastroenterology (1982)
Source url:
Exact phrase from label:
Hypervitaminosis A-related liver toxicity may be severe and may even lead to cirrhosis.
Label source:
PubMed: Liver international : official journal of the International Association for the Study of the Liver (2006)
Source url:
Exact phrase from label:
Serum CRP increased significantly in the obese vitamin A-treated group (P = 0.03) and serum aspartate transaminase increased significantly in the obese and non-obese groups after vitamin A supplementation (P = 0.008 and 0.001, respectively).
Label source:
PubMed: Annals of clinical biochemistry (2013)
Action type:
monitor
Target id:
/intervention/mineral-oil-laxative
Target name:
Mineral Oil (Laxative)
Severity:
moderate
Interaction type:
diminishing
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Long-term use of mineral oil as a laxative can coat the intestines and prevent the absorption of fat-soluble vitamins, leading to deficiency.
Actionable advice:
Long-term, concurrent use of mineral oil and Vitamin A supplements is best avoided.
Validation status:
validated_via_pubmed
Evidence tier:
tier_b
Evidence basis:
pubmed_abstract_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
There have been concerns regarding the interference in the absorption of fat-soluble vitamins in long-term treatment with mineral oil; however, there is no clear evidence in the literature to support this claim.
Label source:
PubMed: Clinical pediatrics (2006)
Action type:
avoid
Target id:
/condition/lactation
Target name:
Breastfeeding (Lactation)
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
While some Vitamin A is necessary, very high maternal doses can pass into breast milk and potentially cause toxicity in the infant.
Actionable advice:
The recommended daily intake for Vitamin A is best not exceeded while breastfeeding without medical advice.
Validation status:
anecdotal
Evidence tier:
tier_d
Evidence basis:
anecdotal_summary
Evidence anchors:
Exact phrase from label:
Fat soluble vitamins like vitamin A can concentrate in breast milk, and excessive amounts of vitamin A can be harmful to a baby.
Label source:
Anecdotal: Healthline
Action type:
informational_none
Target id:
/intervention/vitamin-e
Target name:
Vitamin E
Severity:
minor
Interaction type:
synergistic
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Vitamin E is an antioxidant that may help protect Vitamin A from oxidative damage in the body and can reduce some toxic effects of high Vitamin A doses.
Actionable advice:
Consider taking Vitamin E alongside Vitamin A, as they work together to support cellular health.
Validation status:
validated_via_pubmed
Evidence tier:
tier_b
Evidence basis:
pubmed_abstract_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Over-supplementation of fat-soluble vitamins, such as vitamin A and vitamin E, can result in toxic levels since excess is not excreted in the urine.
Label source:
PubMed: International journal of women's dermatology (2025)
Source url:
Exact phrase from label:
Various substances including vitamin A, vitamin E, polyphenols, peroxisome proliferator-activated receptor gamma ligands, and inhibitors of the renin-angiotensin system show great promise of being useful in the treatment of chronic pancreatitis.
Label source:
PubMed: Journal of gastroenterology (2008)
Source url:
Exact phrase from label:
The plasma vitamin C, vitamin A, vitamin E, and beta-carotene concentrations were lower in the X-ray group than in control although their concentrations were increased by the treatment.
Label source:
PubMed: Cell biochemistry and function (2009)
Action type:
informational_none
Target id:
/intervention/iron-supplements
Target name:
Iron Supplements
Severity:
minor
Interaction type:
synergistic
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Vitamin A is involved in iron metabolism and helps mobilize iron from storage sites. Co-supplementation can be more effective at correcting anemia than iron alone.
Actionable advice:
If you are iron-deficient, ensuring adequate Vitamin A status can improve the effectiveness of iron supplementation.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
RESULTS: Vitamin A can improve haematological indicators and enhance the efficacy of iron supplementation.
Label source:
PubMed: The role of vitamins in the prevention and control of anaemia. (PMID 10948381)
Action type:
informational_none
Target id:
/class/acid-suppressors
Target name:
Gastric Acid Suppressors
Severity:
minor
Interaction type:
diminishing
Nature:
absolute
Description:
Stomach acid is needed to release Vitamin A (as retinyl esters) from protein in food. Long-term use of acid-reducing drugs may slightly impair absorption from dietary sources.
Actionable advice:
Long-term use of PPIs or H2 blockers might slightly reduce Vitamin A absorption from food.
Validation status:
validated_via_class_inference
Evidence tier:
tier_c
Evidence basis:
class_inference_summary
Evidence anchors:
Source url:
Established mechanism / class pharmacology (no single primary source quoted)
Exact phrase from label:
Mechanistic inference: gastric acid helps release vitamin A (retinyl esters) from food/protein, so long-term acid suppression may slightly impair absorption of food-bound vitamin A. Minor, monitoring-level.
Label source:
Class inference
Action type:
informational_none
Temporal spacing:
Hours before target:
0
Hours after target:
0