Vitamin A

Tier-CPublic-ready6/25/2026

Blood-Level or Deficiency Marker is closer to a research marker, so it should be read separately from a directly felt benefit.

Some human supplement-context evidence is present and directly informs the score.

Representative tier calculated from paper evidence that passed the collection audit.

Papers analyzed

Caution signal

Low

Representative score

62.1

Blood-Level or Deficiency MarkerImmune and respiratory supportDigestion and gut comfort

Main benefit evidence

The representative ingredient tier is calculated from these target-level evidence groups.

Nutrient status and deficiency

4 studiesTier-B

Blood-Level or Deficiency Marker

Fairly consistent positive signal in studiesResearch marker focusPatient-group study

This is based on lab markers such as blood levels, deficiency correction, or absorption. Read it separately from directly felt outcomes.

Evidence score

54.6

Study context

Patient-group study

This score reflects the strength of this benefit group. The ingredient tier also considers paper count, repetition, population, and study context.

Immune and respiratory health

2 studiesTier-C

Immune and respiratory support

Some positive signal observedFelt benefit focusSupplement context

Potential benefit studied in Immune and respiratory health.

Evidence score

42.1

Study context

Supplement context

This score reflects the strength of this benefit group. The ingredient tier also considers paper count, repetition, population, and study context.

Digestion and gut health

1 studiesTier-C

Digestion and gut comfort

Some positive signal observedFelt benefit focusPatient-group study

Potential benefit studied in Digestion and gut health. These findings come from a defined study population, so everyday effects may differ.

Evidence score

42.1

Study context

Patient-group study

This score reflects the strength of this benefit group. The ingredient tier also considers paper count, repetition, population, and study context.

Glucose and metabolic health

1 studiesTier-C

Glucose and metabolic health markers

Some positive signal observedResearch marker focusPatient-group study

This card is closer to a measured biomarker or lab outcome than a directly felt user benefit. These findings come from a defined study population, so everyday effects may differ.

Evidence score

20.9

Study context

Patient-group study

This score reflects the strength of this benefit group. The ingredient tier also considers paper count, repetition, population, and study context.

Women's health

2 studiesTier-C

Menstrual and women's health

Signal is still limitedFelt benefit focusPatient-group study

Potential benefit studied in Women's health. These findings come from a defined study population, so everyday effects may differ.

Evidence score

5.9

Study context

Patient-group study

This score reflects the strength of this benefit group. The ingredient tier also considers paper count, repetition, population, and study context.

Recent research

Updated This Month10 new papers

Key cautions to review

Standalone side-effect signals and combination cautions are listed separately.

Caution index

0.9

Caution band: Low

Caution signals

Side effects + combos + curated rules

Key precautions

No curated contraindication rule is available yet, but literature caution signals are shown below.

Standalone side effects, combination cautions, and positive combos are separated below.

Standalone side effects

Adverse effect signal1 papers

Higher serum retinol concentrations were mentioned to be associated with elevated prostate cancer risk in prospective cohort analyses.human · unknown

Vomiting1 papers

Vitamin A supplementation is associated with an increased risk of vomiting within the first 48 hours.human · meta-analysis

Evidence summaries

Paper IDs and full lists are private. Only study types and summaries are shown.

Key Evidence #1

Public scholarly dataCitation signal: 507

observational

New evidence for both prevalence and absolute burden of vitamin A deficiency should be used to reconsider, and possibly revise, the list of priority countries for high-dose vitamin A supplementation such that a country's priority status takes into account both

Key Evidence #2

Public scholarly dataCitation signal: 506

review

To better understand the relationship between nutrition and the immune system, the authors review recent literature about VitA in immunity research and briefly introduce the clinical application of VitA as a therapeutic effect in the treatment of several infec

Key Evidence #3

Public scholarly dataCitation signal: 345

review

Vitamin A supplementation is associated with large reductions in mortality, morbidity, and vision problems in a range of settings, and these results cannot be explained by bias.

3 more summariesLimited representative sample by study type.

Public scholarly dataCitation signal: 337

review

A complex view on the present knowledge about vitamin A ranging from its sources through its physiological functions to consequences of its deficiency and metabolic fate up to possible pharmacological administration and potential toxicity is provided.

Public scholarly dataCitation signal: 275

review

The focus will be directed to the putative or identified proteins participating in the intestinal membrane and cellular transport of vitamin A and carotenoids across the enterocyte (i.e., Scavenger Receptors or Cellular Retinol Binding Proteins, among others).

Public scholarly dataCitation signal: 256

observational

Five years after the clinical trial ended, the beneficial effects of the AREDS formulation persisted for development of NV AMD but not for CGA, consistent with the original recommendations that persons with intermediate AMD or advanced AMD in one eye should co

Vitamin A

Evidence score: 62.1|Caution index: 0.9

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