Supplement evidence

009 / 575Vitamin

Vitamin A

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The short answer

Treating deficiency and meeting essential vision, immune, and developmental needs.

Evidence and scope: Established for an indicated use
This status does not grade the ingredient for every goal, outcome, or person.
Important limitation: Supplementation does not provide a general longevity benefit in well-nourished adults.
Before deciding: Preformed vitamin A can be toxic and teratogenic; beta-carotene supplements raise lung-cancer risk in smokers.

01 / PRACTICAL GUIDE

Dose, absorption, and combinations

These are indication-specific reference or studied ranges—not a personalized prescription. Start with the objective, then check the form, label, medicines, and health conditions.

Reference range by objective

Meeting usual needs700 mcg RAE/day women; 900 mcg RAE/day men

Reference or studied range—not a personalized prescription. The product label or a clinician may specify a different dose.

Dose source ↗

More is not automatically better. A clinician or product label may specify a different amount.

Absorption / solubilityFat-soluble / lipid-based

Fat-soluble or lipid-based. Absorption generally improves with a meal containing fat.

How it is commonly taken

Take with a meal containing fat.

Do not combine casually

Avoid high-dose preformed vitamin A in pregnancy and avoid beta-carotene pills if smoking or asbestos-exposed.

Dose and use source ↗

Dose and use links lead to primary or official source material. Search links are discovery tools, not proof that every returned paper applies.

02 / EVIDENCE

What the research says

We keep supportive, mixed, negative, safety, and contextual findings together. The headline never replaces the underlying papers.

4research papers in this ledger

120unique primary studies represented

1,671,672unique participants represented

These are audited counts for this JIVANA collection, not search-result totals. Participants are counted once when multiple papers use the same cohort; review papers are not added again to participant totals.

Open the research timelineResearch timeline

Entries are ordered by publication year. A study period appears only when the source reports it.

2024

Mixed or qualifiedPMID 38816049 · CRD42018104347

Effects of primary or secondary prevention with vitamin A supplementation on clinically important outcomes

Moderate-certainty evidence from individually randomized trials found no mortality reduction in children or adults. A mortality signal in cluster trials was very low certainty, and serious adverse events and quality of life were poorly reported.

Published: 2024n=1,671,672 participants120 primary studies represented

Study design and methods

Design: Systematic review and meta-analysis of 120 randomized trials
Population: 1,671,672 children and adults across 105 individually randomized and 15 cluster-randomized trials
Intervention: Vitamin A supplements versus placebo or no intervention
Outcome: Mortality, serious adverse events, quality of life, and blindness

Funding or conflict note: The authors declared no competing interests.

Open research record ↗

2016

Does not support the tested claimPMID 27012320

Vitamin A supplementation for postpartum women

Supplementation increased breast-milk retinol but did not demonstrate maternal or infant mortality or morbidity benefit. Biomarker improvement did not translate into measured clinical benefit.

Published: 2016n=25,758 participants14 primary studies represented

Study design and methods

Design: Cochrane systematic review of 14 randomized or cluster-randomized trials
Population: 25,758 postpartum women and infant pairs, largely in deficiency-affected settings
Intervention: High-dose vitamin A or daily beta-carotene versus placebo, no treatment, or another dose
Outcome: Maternal and infant mortality and morbidity, breast-milk retinol, and adverse outcomes

Funding or conflict note: The authors reported no known conflicts. These trials are represented in the broader 2024 synthesis.

Open research record ↗

2010

Supports a specific usePMID 21154399

Vitamin A supplementation for preventing morbidity and mortality in children from 6 months to 5 years of age

Vitamin A reduced mortality and diarrheal illness in these child populations, while vomiting was more common shortly after dosing. This does not support routine high-dose use in well-nourished adults.

Published: 2010n=215,633 participants43 primary studies represented

Study design and methods

Design: Cochrane systematic review of 43 randomized or cluster-randomized trials
Population: 215,633 community-dwelling children aged 6 months to 5 years, mainly where deficiency was a public-health problem
Intervention: Synthetic vitamin A supplementation versus control
Outcome: All-cause and cause-specific mortality, illness, vision, and short-term adverse effects

Funding or conflict note: These trials are represented in the broader 2024 synthesis and are excluded from aggregate totals.

Open research record ↗

1996

Safety signalPMID 8901853

Risk factors for lung cancer and for intervention effects in CARET

The trial stopped early for harm: the combination increased lung cancer and mortality rather than preventing cancer. This result applies to the tested high-risk population and combined high-dose regimen.

Published: 1996n=18,314 participants

Study design and methods

Design: Randomized, double-blind, placebo-controlled chemoprevention trial
Population: 18,314 smokers and asbestos-exposed adults at high lung-cancer risk
Intervention: Beta-carotene 30 mg plus retinyl palmitate 25,000 IU/day versus placebo
Outcome: Lung-cancer incidence, lung-cancer mortality, and total mortality

Funding or conflict note: This trial is represented in the 2024 prevention synthesis and is excluded from aggregate totals.

Open research record ↗

Unscreened discovery appendix—not evidence1,645 candidate publicationsSearch run: Aug 21, 2026

Complete for the displayed PubMed query at the search timestamp—not for all databases or every possible synonym. Candidates can be irrelevant, duplicate the same study, or report negative findings. They are never summed as evidence or participants until screened.

03 / SOURCES

Start with the source material

Official evidence overviewNIH Office of Dietary Supplements Live PubMed discovery searchNational Library of Medicine

The live search is for discovery only. Search-result counts change and are not included in the audited totals above.

Recent PubMed discovery recordsDirect links to the first 12 records returned by the reproducible search. These are discovery candidates—not reviewed summaries or a count of supportive findings.

04 / EXPERT CONTEXT

Expert context—not evidence

Expert positions are dated context—not scientific evidence. They never raise the evidence status or become consensus by repetition.

No direct, source-verified endorsement is currently recorded. Research authorship or discussion alone is not treated as endorsement.