Vitamin A: Retinol, Beta-Carotene, Food Sources, Deficiency and Safety
Vitamin A explained: retinol versus beta-carotene, food sources, deficiency, official intake levels and upper limits from the US, UK and EU, pregnancy and smoking cautions.
Content last updated . This page has not been medically reviewed.
What is Vitamin A good for?
What the body uses it for, and how strong the evidence is. A normal job in the body is not proof that extra supplements add benefit; each card says which.
Vision in dim light
Established roleVitamin A helps the eyes see in low light. Lack of it causes night blindness.
Supplements: Supplements correct deficiency; Proper evidence not found that extra vitamin A improves eyesight in well-nourished people.
Healthy eye surface (cornea)
Deficiency linkEnough vitamin A keeps the clear front of the eye healthy. Long-term lack can cause lasting damage to the cornea (xerophthalmia).
Supplements: Relevant mainly where intake is low; not shown to help eyes when intake is adequate.
Immune system function
Established roleVitamin A supports the body's defences against infection.
Supplements: Benefit shown in children at risk of deficiency; not shown to boost immunity in well-fed people.
Skin and body linings
Established roleVitamin A helps keep skin and the lining of surfaces such as the nose healthy. Low intake can cause dry, scaly skin.
Supplements: Corrects deficiency-related skin changes; no good evidence of extra benefit with adequate intake.
Bone and teeth formation
Established roleVitamin A helps form and maintain bones and teeth. Too much preformed vitamin A over many years may weaken bones.
Supplements: Adequate intake matters; extra supplements are not shown to strengthen bones and high intake is linked to more hip fracture.
Soft tissue formation and maintenance
Established roleVitamin A helps form and maintain soft tissues in the body.
Supplements: Supplements matter only when intake is low.
Antioxidant activity of beta-carotene
Lab or animal research onlyBeta-carotene, which the body can turn into vitamin A, acts as an antioxidant.
Supplements: Antioxidant activity does not mean supplements protect health; beta-carotene supplements raised lung cancer risk in male smokers.
Storage in the liver
Established roleThe body stores vitamin A in the liver, so it is not needed every day. This is also why too much can build up.
Supplements: Storage means deficiency is rare in well-fed people and excess is the more common safety concern.
Connected topics
Open a group to see how each topic connects and how strong the evidence is.
Health goals (3)
- Healthy SkinEstablished role
Vitamin A helps keep skin healthy and low intake causes dry, scaly skin. No good evidence that extra improves skin when intake is adequate.
- Immune SupportEstablished role
Vitamin A supports the immune system. Benefit is clear where deficiency is common; extra supplements are not shown to boost immunity in well-fed people.
- Bone HealthEstablished role
Vitamin A helps form and maintain bones, but high long-term intake of preformed vitamin A is linked to more fractures, so more is not better.
Body systems (7)
- Immune SupportEstablished role
Vitamin A supports the immune system; strongest evidence is in children at risk of deficiency.
- Immune SystemEstablished role
Vitamin A supports the immune system; strongest evidence is in children at risk of deficiency.
- Integumentary SystemEstablished role
Vitamin A helps maintain skin; deficiency can cause dry, scaly skin.
- Skin, Hair & BeautyEstablished role
Vitamin A helps keep skin healthy. The sources read do not cover hair benefits.
- Bones, Joints & MusclesEstablished role
Vitamin A helps form and maintain bones, but too much preformed vitamin A may raise fracture risk.
- Hepatic / Liver SystemDocumented risk
The liver stores vitamin A; very high levels are linked with an enlarged liver.
- Musculoskeletal SystemEstablished role
Vitamin A helps form and maintain bones, but too much preformed vitamin A may raise fracture risk.
Body parts (5)
- EyesEstablished role
Vitamin A is needed for sight in dim light and a healthy cornea. Deficiency causes night blindness and corneal damage.
- Immune SystemEstablished role
Vitamin A supports the immune system; strongest evidence is in children at risk of deficiency.
- LiverDocumented risk
The liver stores vitamin A, and very high levels are linked with an enlarged liver. Liver foods are very rich sources.
- SkinEstablished role
Vitamin A helps maintain skin; low intake causes dry, scaly skin.
- BonesEstablished role
Vitamin A helps form and maintain bones, but high long-term intake of preformed vitamin A is linked to more hip fracture.
Root causes (4)
- Nutrient DeficiencyDeficiency link
Low vitamin A intake causes night blindness, corneal damage and dry skin. It is rare in the US but a major problem in many low-income countries.
- Digestive DysfunctionDeficiency link
Conditions that impair fat absorption, such as cystic fibrosis, pancreatitis and celiac disease, can lower vitamin A levels.
- Medication Side EffectsDocumented risk
Vitamin A supplements may interact with isotretinoin, an acne medicine that can cause birth defects.
- Poor DietDeficiency link
Low intake of vitamin A foods raises the risk of deficiency; most people can get enough from a varied diet.
Habits (1)
- Balanced NutritionEstablished role
A varied diet usually gives enough vitamin A. Eating liver more than once a week can push intake too high.
Conditions & symptoms (12)
- HypervitaminosisDocumented risk
Too much preformed vitamin A builds up and can cause serious harm; chronic poisoning may occur above about 33,000 IU a day, and children are more sensitive. Generic slug; a specific vitamin A toxicity term is proposed.
- NyctalopiaDeficiency link
Low vitamin A intake causes night blindness, which is reversible. db_slug 'nyctalopia' is the general term; the genetic 'Night Blindness, Congenital Stationary' is not a match.
- TeratogenesisDocumented risk
Large doses of vitamin A in pregnancy can cause birth defects.
- Vitamin A DeficiencyDeficiency link
Low vitamin A intake is the cause. In a Cochrane review, supplements lowered deficiency, night blindness and Bitot's spots in children where it is common.
- XerophthalmiaDeficiency link
Long-term low vitamin A can cause lasting damage to the cornea.
- DiarrheaClinically supported
In children aged 6 months to 5 years where deficiency is common, supplements cut diarrhoea deaths by 12% and diarrhoea cases (low-certainty). Does not apply to well-fed children.
- HyperkeratosisDeficiency link
Low intake can cause dry, scaly skin.
- Lung NeoplasmsDocumented risk
In a trial of male smokers, 20 mg beta-carotene a day was linked to 18% more lung cancer.
- OsteoporosisDocumented risk
The NHS says long-term intake above 1.5 mg a day may make bones more likely to fracture; a meta-analysis of prospective studies found high preformed vitamin A intake linked to more hip fracture (observational).
- HepatomegalyDocumented risk
The blood test page lists an enlarged liver with high vitamin A levels.
- Intracranial HypertensionDocumented risk
The blood test page lists increased pressure in the brain with high vitamin A levels.
- MeaslesPreliminary or mixed
In the same review measles cases fell (low-certainty, 2 studies) but there was no difference in measles deaths.
Documented risks and interactions (2)
- Birth defect risk from large amounts. Large amounts of preformed vitamin A in pregnancy can cause birth defects, so pregnant women are told to avoid vitamin A supplements, cod liver oil and liver.
- Medicine interaction with isotretinoin. Vitamin A supplements may interact with isotretinoin, an acne medicine that can cause birth defects.
Safety first
Too much preformed vitamin A (retinol) can harm: it builds up in the liver, and large amounts in pregnancy can cause birth defects. [1][2] The NHS (UK) tells pregnant women not to take supplements containing vitamin A (retinol) or cod liver oil, and to avoid liver. [2] If a child may have swallowed vitamin A products, call Poison Help at 1-800-222-1222 in the US (911 for an emergency); see Poison help by country. Details are on Vitamin A excess, pregnancy and retinoid medicines.Overview
Vitamin A is a fat-soluble vitamin that the liver stores. It helps vision in dim light, the immune system, and the skin and the lining of body surfaces such as the nose. [3][1] The NHS says you should be able to get all the vitamin A you need from a varied diet. [3] For most readers the main safety question is too much, not too little.Evidence labels used on this page: established nutritional role / deficiency treatment, evidence in adequately nourished people, mixed, insufficient evidence, harm signal. Where we looked and found nothing usable we write Proper evidence not found.
Retinol, retinyl esters and beta-carotene
- Preformed vitamin A is retinol and its esters. MedlinePlus says supplements most often contain retinyl acetate or retinyl palmitate, beta-carotene, or a mix. [1]
- Provitamin A carotenoids come from plants. The best known is beta-carotene, which the body converts to vitamin A. [1] MedlinePlus counts more than 500 known carotenoids. [1]
- Do not carry results from one form to another. Trials of beta-carotene and of retinyl palmitate are not trials of food.
Food sources
NHS (UK) sources of retinol include cheese, eggs, oily fish, fortified low-fat spreads, milk and yogurt, and liver, which is a particularly rich source. [3] Beta-carotene comes from yellow, red and green leafy vegetables and from yellow fruit. [3] MedlinePlus says carotenoid absorption improves when these foods are eaten with a little fat. [1] See Foods high in vitamin A and Carotenoids.Who may need assessment
Deficiency is very rare in the United States, according to MedlinePlus. [1] It is a major public health problem in low- and middle-income countries, where a Cochrane review counted 190 million affected children under five. [4] In wealthy countries, poor fat absorption or limited diets are reasons to talk with a clinician, not to self-treat. See Deficiency testing and its limits.Deficiency
Low intake raises the risk of reversible night blindness, non-reversible corneal damage (xerophthalmia) and dry, scaly skin. [1] Suspected deficiency needs a clinician; do not diagnose it from symptoms.Evidence by specific use
| Question | What the source found | Label |
|---|---|---|
| Night blindness, xerophthalmia | Caused by lack of vitamin A [1] | Established |
| Death in young children where deficiency is common | Cochrane review of 47 trials (about 1.2 million children aged 6 months to 5 years, mostly in Asia and Africa): 12% fewer deaths from any cause (risk ratio 0.88, 19 trials) with synthetic vitamin A. No difference for measles deaths. [4] | Established where deficiency is common; does not transfer to well-fed children |
| Cancer prevention with beta-carotene supplements | Male smokers given 20 mg a day: 18% more lung cancer [5]. Smokers, former smokers and asbestos-exposed workers given 30 mg beta-carotene plus 25,000 IU retinol a day: relative risk of lung cancer 1.28 [6]. Male physicians given 50 mg every other day for 12 years: neither benefit nor harm [7] | Harm signal in smokers; no benefit in others |
| Death from any cause, antioxidant supplements | Cochrane review of 78 trials: beta-carotene and vitamin E seem to increase mortality, "and so may higher doses of vitamin A" [8] | Mixed to harm signal |
| Hip fracture | Meta-analysis of 8 intake studies (283,930 people): high vitamin A and retinol intake linked to more hip fracture; beta-carotene intake was not [9]. These are observational findings | Mixed |
| Better eyesight in well-nourished people | Proper evidence not found in NHS or MedlinePlus pages, or in the trials above | Insufficient evidence |
Official intake levels
These are not targets for everyone and are not personal advice. Units differ between countries: UK figures use retinol equivalents (RE) and the US label uses retinol activity equivalents (RAE). See Vitamin units explained and RDA, AI, DV and UL.| Source and year | Population | Amount per day |
|---|---|---|
| US Dietary Reference Intakes via MedlinePlus (reviewed 2025) | Infants 0 to 6 and 7 to 12 months (AI) | 400 and 500 mcg [1] |
| Same | Children 1 to 3, 4 to 8, 9 to 13 years (RDA) | 300, 400, 600 mcg [1] |
| Same | Males 14 and older; females 14 and older (RDA) | 900 mcg; 700 mcg [1] |
| Same | Females 19 to 50: pregnancy; breastfeeding | 770 mcg; 1,300 mcg [1] |
| NHS (UK), reviewed 2020 | Adults 19 to 64 | 700 mcg for men, 600 mcg for women [3] |
| Daily Value on US labels (FDA) | Label reference, not a requirement | 900 mcg RAE [10] |
| EFSA (EU) Tolerable Upper Intake Level, overview version August 2025 | Preformed vitamin A (retinol and esters), adults, pregnancy and lactation | 3,000 mcg RE [11] |
| Same | Children 1 to 3, 4 to 6, 7 to 10, 11 to 14, 15 to 17 years | 800, 1,100, 1,500, 2,000, 2,600 mcg RE [11] |
| NHS (UK) advice on bones | Postmenopausal women and older men: food and supplements combined | No more than 1,500 mcg a day [3] |
EFSA states no adequate data to derive an upper level for beta-carotene, and that smokers should avoid beta-carotene food supplements. [11] NHS (UK) advises no more than 7 mg a day of beta-carotene supplements unless a doctor advises, and none for people who smoke or have been exposed to asbestos. [12]
Too much vitamin A
- MedlinePlus says chronic poisoning may occur in adults who regularly take more than 33,000 IU a day, and children are more sensitive. [1]
- The NHS says an average of more than 1,500 mcg a day over many years may make bones more likely to fracture, and advises against liver more than once a week and against vitamin A supplements if you eat liver weekly. [3]
- Large amounts of beta-carotene will not make you seriously ill but can turn skin yellow or orange, which fades. [1]
- Many multivitamins and fish liver oils contain vitamin A. [3] See Amounts and duplicate ingredients and Cod liver oil.
Medicines, pregnancy, children and other conditions
- Medicines: MedlinePlus lists vitamin A supplements among products that may interact with isotretinoin, a prescription acne medicine that can cause birth defects. [13] Read How interactions work and ask a pharmacist. Do not stop a prescribed medicine on your own.
- Pregnancy and breastfeeding: MedlinePlus says large doses can cause birth defects. [1] NHS foods-to-avoid advice says liver and foods containing liver have high levels of vitamin A. [14] Ask your midwife or doctor about the advice for your country; see Pregnancy and breastfeeding safety.
- Children: babies and children can become sick on smaller amounts. [1] Keep products out of reach.
- Older adults: the NHS bone advice above is aimed at this group. [3]
- Liver and kidney disease, surgery: we did not find a source we could read that gives vitamin A advice for these. Ask a clinician; see Vitamins and kidney or liver disease and Vitamins before surgery.
Testing
A vitamin A blood test exists. MedlinePlus lists 30 to 120 mcg/dL as a typical range and says ranges vary by lab. [15] It is not a routine check for healthy people, and a result is read by a clinician with your history.Labels and quality
Check whether the label shows retinol, retinyl esters or beta-carotene, and the unit (mcg RAE, IU). Read Reading supplement labels and Quality testing and certifications.Frequently asked questions
Is vitamin A the same as beta-carotene?
No. Retinol is found in animal foods and many supplements; beta-carotene is a plant pigment the body can convert into vitamin A. [1]
Is it safe to take vitamin A in pregnancy?
Large doses can cause birth defects, and the NHS advises against vitamin A (retinol) supplements, cod liver oil and liver in pregnancy. Ask a midwife or doctor before any supplement. [1][2]
Should smokers take beta-carotene supplements?
The NHS and EFSA advise against it, after trials in smokers and asbestos-exposed workers found more lung cancer. [12][11][5][6]
Does vitamin A improve eyesight?
It supports vision in dim light and lack of it causes night blindness. Proper evidence not found that extra vitamin A improves eyesight in well-nourished people. [1]
Can I get too much from food?
Liver is the main risk: the NHS says eating it more than once a week may give too much. Carotenoids from plant foods have no such concern, though large amounts can tint skin. [3][1]
References
- MedlinePlus, U.S. National Library of Medicine. Vitamin A (encyclopedia article, reviewed 1/21/2025). Read 2026-10-22.
- NHS (UK). Pregnancy vitamins and supplements. Read 2026-10-22.
- NHS (UK). Vitamins and minerals: Vitamin A. Page last reviewed 3 August 2020. Read 2026-10-22.
- Imdad et al. 2022. Vitamin A supplementation for preventing morbidity and mortality in children from six months to five years of age. Cochrane Database Syst Rev. PMID 35294044. Read 2026-10-22.
- Alpha-Tocopherol, Beta Carotene Cancer Prevention Study Group. 1994. The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers. N Engl J Med. PMID 8127329. Read 2026-10-22.
- Omenn et al. 1996. Effects of a combination of beta carotene and vitamin A on lung cancer and cardiovascular disease. N Engl J Med. PMID 8602180. Read 2026-10-22.
- Hennekens et al. 1996. Lack of effect of long-term supplementation with beta carotene on the incidence of malignant neoplasms and cardiovascular disease. N Engl J Med. PMID 8602179. Read 2026-10-22.
- Bjelakovic et al. 2012. Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases. Cochrane Database Syst Rev. PMID 22419320. Read 2026-10-22.
- Wu et al. 2014. The relationship between vitamin A and risk of fracture: meta-analysis of prospective studies. J Bone Miner Res. PMID 24700407. Read 2026-10-22.
- U.S. Food and Drug Administration. The Daily Value on the Nutrition and Supplement Facts Labels. Read 2026-10-22.
- European Food Safety Authority. Overview on Tolerable Upper Intake Levels as derived by the Scientific Committee on Food (SCF) and the EFSA NDA Panel. Version 11, August 2025 (Table 3, vitamins). Read 2026-10-22.
- NHS (UK). Vitamins and minerals: Others (beta-carotene). Page last reviewed 3 August 2020. Read 2026-10-22.
- MedlinePlus, U.S. National Library of Medicine. Isotretinoin (drug information). Read 2026-10-22.
- NHS (UK). Foods to avoid in pregnancy. Read 2026-10-22.
- MedlinePlus, U.S. National Library of Medicine. Vitamin A blood test (encyclopedia article). Read 2026-10-22.