A woman holding freshly picked carrots in an allotment. Carrots are a rich source of vitamin A

What does vitamin A do and why do we need it?

Find out all about vitamin A, including what it does, how much you need, where to find it, and who might need to supplement their diet

Overview of vitamin A

What is vitamin A and what does it do?

Vitamin A is the collective term for a group of fat-soluble nutrients. The body stores excess vitamin A in the liver until it’s needed, so we don’t need a daily supply. However, we should still aim to eat enough over a week.1 Vitamin A helps support:2
  • healthy vision and skin
  • cell growth
  • normal immune system function
  • the use of iron in the body
Vitamin A comes in two main forms: retinol, from animal products, and carotenoids or beta-carotene, found in certain fruits and vegetables including carrots, spinach and sweet potatoes. Our bodies convert beta-carotene into vitamin A.3 Most people get all the vitamin A they need from their diet but some groups, such as vegans, can have low intakes.4

Functions of vitamin A

What does vitamin A do in the body?

Vitamin A is vital for eye health – particularly your retina – and affects how well you see in the dark. Your cells use vitamin A to reproduce and grow, which is particularly important for skin health as skin has a high turnover of cells.6 Your immune system uses vitamin A to help it to ward off illness and infection.7

How much vitamin A do I need?

The amount of vitamin A you need depends on the Reference Nutrient Intake (RNI) for your age and sex.

Women need 600 mcg of vitamin A per day and men 700 mcg.8 A medium sweet potato gives you around 1100 mcg and a medium raw carrot about 500 mcg.9

How much vitamin A do children need?

  • 1-6 years – 400 mcg daily
  • 7-10 years – 500 mcg daily
  • 11-14 years – 600 mcg daily10

Vitamin A foods

Which foods are the best sources of vitamin A?

Food sources of vitamin A (retinol) include:11,12
  • milk
  • cheese and yogurt
  • fortified low-fat spreads
  • eggs
  • liver
  • oily fish, like salmon
Rich sources of carotenoids and beta-carotene include:13
  • carrots
  • squash
  • mangoes
  • peppers
  • orange juice
  • spinach
  • sweet potatoes

Vitamin A deficiency

What are the symptoms of a vitamin A deficiency?

Vitamin A deficiency in the UK is rare.14 However, low levels could affect your night vision and lead to night blindness. It can also put you at greater risk of infection.15 Other symptoms include dry skin, flaky scalp, brittle hair and impaired eyesight.16

What happens if I consume too much vitamin A?

You’d need to take a dose hundreds of times over the RNI for vitamin A to be harmful in the short term.17 But consuming three times the RNI every day over many years may affect bone and liver health.18 The NHS advises restricting liver and liver pâté to once a week or less. Make sure any vitamin A supplement you’re taking doesn’t exceed 1.5 mg a day19 and be careful that you’re not doubling up on vitamin A from different sources – for example, taking cod liver oil plus a multivitamin.

Vitamin A supplements

When should I take vitamin A supplements?

Vitamin A is fat-soluble (stored in the body), so it’s not necessary to have it every day. In the UK, the only people who need to take a supplement are those who have trouble absorbing vitamin A or who don’t eat enough vitamin A-rich foods.20

Should children take vitamin A supplements?

The government recommends children aged six months to five years take a daily multivitamin containing vitamin A.21

Should women take a vitamin A supplement during pregnancy?

Too much vitamin A could damage the health of an unborn baby. Pregnant women shouldn’t take supplements containing vitamin A, unless advised by a doctor, and should avoid eating liver and pâté which are both naturally high in retinol.22

What are the potential benefits of taking a vitamin A supplement?

A 2005 study found vitamin A supplements can help support the immune system.23 A 2001 study reported that vitamin A supplements can help to target inflammation24, which has been linked to obesity and the development of certain chronic diseases. Shop Vitamins Advice is for information only and should not replace medical care. Please check with your GP before trying any remedies. Written by Rosalind Ryan on October 19, 2018 Reviewed by Dr Carrie Ruxton PhD on November 3, 2018
Sources
  1. 1. HSIS. Vitamin A (Retinol). Available from: www.hsis.org/a-z-food-supplements/vitamin-a/
  2. . NHS. Vitamin A. Available from: www.nhs.uk/conditions/vitamins-and-minerals/vitamin-a/
  3. . As above
  4. . NHS. Vitamins for children. Available from: www.nhs.uk/conditions/pregnancy-and-baby/vitamins-for-children/
  5. . As Source 1
  6. . Harvard T.H. Chan School of Public Health. Vitamin A. Available from: www.hsph.harvard.edu/nutritionsource/vitamin-a/
  7. . As Source 2
  8. . As Source 2
  9. . Dietitians of Canada. Food Sources of Vitamin A. Available from: www.dietitians.ca/Downloads/Factsheets/Food-Sources-of-Vitamin-A.aspx
  10. . Public Health England. Government Dietary Recommendations. Available from: www.assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/618167/government_dietary_recommendations.pdf
  11. . National Institutes of Health. Vitamin A. Available from: www.ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/
  12. . As Source 2
  13. . As Source 11
  14. . As Source 1
  15. . Food Standards Agency. Safe Upper Level for Vitamins and Minerals. Available from: www.cot.food.gov.uk/sites/default/files/cot/vitmin2003.pdf
  16. . As Source 1
  17. . As Source 15
  18. . As Source 15
  19. . As Source 2
  20. . As Source 11
  21. . As Source 4
  22. . As Source 2
  23. . Villamor E, Fawzi WW. Effects of Vitamin A Supplementation on Immune Responses and Correlation with Clinical Outcomes. Available from: www.ncbi.nlm.nih.gov/pmc/articles/PMC1195969/
  24. . Reifen R. Vitamin A as an anti-inflammatory agent. Available from: www.ncbi.nlm.nih.gov/pubmed/12230799
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