In short:
- Vitamin A is a fat-soluble vitamin that is essential for vision, immunity and skin health.
- Most adults get enough vitamin A from a varied diet — a supplement is only necessary in specific cases.
- Too much vitamin A in the retinol form is toxic, so do not exceed the recommended upper limit of 3000 μg RAE per day.
- When planning a pregnancy and during pregnancy, you need to be especially careful with vitamin A supplements.
Vitamin A for beginners can seem like a confusing topic — the market offers both retinol products and beta-carotene supplements, and the recommendations vary. This practical guide sums up what every beginner should know: how much you need per day, which sources provide it and when a supplement is actually justified.
What should beginners know about vitamin A?
Vitamin A is a fat-soluble vitamin that the body cannot produce on its own, so you need to get it from food or, when necessary, from supplements. It plays four main roles: it supports vision in dim light, supports the work of the immune system, regulates cell differentiation, and maintains the integrity of the skin and mucous membranes (Penniston & Tanumihardjo, 2006).
The vitamin comes in two main forms. Retinol (preformed vitamin A) is found in animal foods — liver, egg yolk, whole milk and butter. Beta-carotene is a plant-based provitamin that the body converts into retinol as needed; it is found in carrots, sweet potatoes, kale and spinach.
Like vitamin D and vitamin B, vitamin A is one of the essential nutrients with a broad effect on the whole body — so it is important to understand the risks of both deficiency and excess.
How much vitamin A do you need per day?
The European Food Safety Authority (EFSA) has set the recommended daily intake for adults at 650 μg RE for women and 750 μg RE for men (EFSA, 2015). The recommendations of the NIH Office of Dietary Supplements are slightly higher: 700 μg RAE per day for women and 900 μg RAE for men (NIH ODS, 2023).
The upper limit deserves attention: both European and American authorities recommend not exceeding 3000 μg RAE per day of vitamin A in the retinol form, because chronic excess can damage the liver and bones (Penniston & Tanumihardjo, 2006). No toxicity from beta-carotene has been described in healthy adults — the body regulates the conversion itself.
Which foods contain the most vitamin A?
Best animal sources (retinol):
– Beef liver (about 100 g contains over 6000 μg RAE — several times the daily amount)
– Cod liver oil
– Eggs and whole-milk dairy products
Best plant sources (beta-carotene):
– Carrot (about 100 g contains about 835 μg RAE)
– Sweet potato
– Kale, spinach, broccoli
– Ripe mango and apricot
An adult who eats a varied diet generally covers their vitamin A needs from food. You can find more detailed information on reference values and food sources in the nutrition recommendations of the Estonian Health Board.
When is a vitamin A supplement justified?
Most healthy adults in Estonia do not need a supplement. However, the following situations may justify one:
- A chronic digestive disorder (e.g. Crohn’s disease, celiac disease, pancreatic disease) that limits the absorption of fat-soluble vitamins.
- A long-term very low-fat diet, because vitamin A needs dietary fat to be absorbed.
- A clinically identified deficiency — diagnosed by a doctor, e.g. in the case of difficulty seeing at night or frequent infections.
- The diet is monotonous and good sources of vitamin A are scarce — in developing countries this is a major public health problem (Sommer, 2008).
If you are considering taking a supplement, consult a doctor or a nutrition counselor first. It is also worth being aware of how other fat-soluble vitamins work — vitamin D is also fat-soluble and follows a similar absorption logic. Vitamin C, on the other hand, is water-soluble and its risk of overdose is considerably lower.
What should you consider before starting a vitamin A supplement?
Pregnancy and the planning period. Excess vitamin A in the retinol form is teratogenic — high doses can harm fetal development (Penniston & Tanumihardjo, 2006). Pregnant women and women planning a pregnancy must not use retinol-based supplements above 800 μg per day without a doctor’s supervision.
Smokers and beta-carotene. Clinical trials (ATBC, CARET) have shown that high-dose beta-carotene supplements may increase the risk of lung cancer in smokers. Therefore, smokers should avoid high-dose beta-carotene supplements.
Interactions with medications. Retinoids may interact with cholesterol-lowering and blood-thinning medications. Tell your doctor about all the supplements you take.
Choosing a supplement. A multivitamin containing a moderate amount of vitamin A (no more than 100% of the daily recommendation) is preferable to an isolated high-dose retinol product.
References
- Penniston KL, Tanumihardjo SA. (2006). The acute and chronic toxic effects of vitamin A. Am J Clin Nutr. 83(2):191–201. PMID: 16469975
- EFSA NDA Panel. (2015). Scientific Opinion on Dietary Reference Values for vitamin A. EFSA Journal. 13(3):4028. DOI: 10.2903/j.efsa.2015.4028
- NIH Office of Dietary Supplements. (2023). Vitamin A — Health Professional Fact Sheet. https://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/
- Sommer A. (2008). Vitamin A deficiency and clinical disease: an historical overview. J Nutr. 138(10):1835–1839. PMID: 18806089
Frequently asked questions
Can you get enough vitamin A from food if you eat a varied diet?
Yes, most adults in Estonia get enough vitamin A from a varied diet. A supplement is only necessary in the case of certain digestive disorders, special diets or a deficiency identified by a doctor.
What is the difference between retinol and vitamin A from beta-carotene?
Retinol is preformed vitamin A found in animal foods — the body uses it directly. Beta-carotene is a plant precursor that the body converts as needed. Beta-carotene is safer in terms of overdose, but smokers are advised to avoid high-dose supplements of it.
Is vitamin A deficiency easy to recognize on your own?
An early sign is night blindness — difficulty seeing in dim light. Later, dry skin and frequent infections may appear. A blood test that measures serum retinol gives an accurate diagnosis.
Is a vitamin A supplement suitable for daily use?
A moderate amount in a multivitamin is usually safe. Isolated high-dose retinol products are not suitable for long-term daily use without a medical need, because retinol, as a fat-soluble vitamin, accumulates in the body.
Can you take a vitamin A supplement during pregnancy?
Not without a doctor’s recommendation. Excess vitamin A in the retinol form is teratogenic and can harm fetal development. Pregnant women should stick to the amounts recommended by their doctor, which do not exceed 800 μg per day.
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