Studies
Explore research connecting ingredients and health goals.
25 ingredient–goal connections
ImmunityandVitamin A
107published studies
Vitamin A deficiency can impair immune function, and the supplied evidence supports benefits from improving status in some deficient populations. Research in children with low vitamin A status reports improvements in selected immune responses, while treatment studies in children with complicated measles show reduced illness burden. These findings are more specific than a general claim that extra vitamin A prevents infections.
Results for respiratory infections and vaccine responses are inconsistent. Some studies report benefit, while others find no improvement in infection occurrence, recovery, or antibody responses. Low vitamin A levels during illness are also not straightforward evidence of causation: infection itself can lower circulating levels. Findings based on blood markers do not necessarily predict fewer infections.
Supplementation has reduced some immune-cell measures in older adults and transiently altered immune development in newborns, with uncertain clinical significance. Overall, the evidence favors distinguishing deficiency-related benefits and specific medical uses from routine supplementation in people who already have enough vitamin A.
107 linked studies · 32 sampled for detail · Sep 27, 2026
Study types
- Narrative review36
- Randomized trial34
- Case-control study9
- Cross-sectional study9
- Cohort study8
- Observational study4
- Meta-analysis2
- Single-arm trial2
- Systematic review2
- Non-randomized trial1
Published by year
- 45Earlier
- 02010
- 52011
- 32012
- 32013
- 22014
- 32015
- 32016
- 22017
- 22018
- 22019
- 32020
- 62021
- 112022
- 42023
- 42024
- 42025
- 52026
Findings over time
Numbers above bars show study counts. Earlier groups years before 2010.
20265 studies
- Supportive1(20%)
- Mixed1(20%)
- No effect3(60%)
- Adverse0(0%)
- Unclassified0(0%)
Population over time
Reported participants by publication year. Select a year to see the total and reporting coverage.
— Participant count not reported. Earlier groups years before 2010.
20267,574,006 reported participants
Counts reported by 5 of 5 studies.
Totals sum reported counts across studies and reviews; participants may overlap between sources.
Showing 5 top-ranked studies for Vitamin A and Immunity.
Top studies
Vitamin A · ImmunityHighest ranked first- Depressed immune response to tetanus in children with vitamin A deficiency.SupportiveView source for Depressed immune response to tetanus in children with vitamin A deficiency. (opens in a new tab)
The Journal of nutrition
Finding After adjustment for prior immunization, vitamin A recipients had a significantly greater tetanus IgG response than placebo recipients in both clinical-status groups.
- Impact of a single megadose of vitamin A at delivery on breastmilk of mothers and morbidity of their infants.SupportiveView source for Impact of a single megadose of vitamin A at delivery on breastmilk of mothers and morbidity of their infants. (opens in a new tab)
European journal of clinical nutrition
Finding Supplementation raised breastmilk retinol at 24 hours and the difference remained for six months.
- Vitamin A supplementation reduces measles morbidity in young African children: a randomized, placebo-controlled, double-blind trial.SupportiveView source for Vitamin A supplementation reduces measles morbidity in young African children: a randomized, placebo-controlled, double-blind trial. (opens in a new tab)
The American journal of clinical nutrition
Finding Vitamin A reduced integrated morbidity scores at day 8, 6 weeks, and 6 months, mainly because of reduced respiratory-tract infection.
- Vitamin A supplementation enhances specific IgG antibody levels and total lymphocyte numbers while improving morbidity in measles.SupportiveView source for Vitamin A supplementation enhances specific IgG antibody levels and total lymphocyte numbers while improving morbidity in measles. (opens in a new tab)
The Pediatric infectious disease journal
Finding Vitamin A supplementation significantly reduced acute and chronic morbidity.
- Vitamin A supplementation reduces the monocyte chemoattractant protein-1 intestinal immune response of Mexican children.SupportiveView source for Vitamin A supplementation reduces the monocyte chemoattractant protein-1 intestinal immune response of Mexican children. (opens in a new tab)
The Journal of nutrition
Finding Vitamin A recipients had lower fecal MCP-1 concentrations than placebo recipients in the overall sample.
Counts reflect published studies in our database, not the strength of a benefit. A study may appear in more than one connection.