Vitamin A

Vitamin A is an essential nutrient that plays an important role in vision, the the immune system and cell growth.

What is vitamin A?

Vitamin A is an essential nutrient that plays an important role in vision, the the immune system and cell growth. It is also known as retinol.

It is available in two forms:

  • Preformed vitamin A – also known as retinyl ester – is found in animal and dairy products. In the UK, preformed vitamin A is also added to fat spreads, such as margarine.
  • Carotenoids – found in plant-based products, such as fruit and vegetables. The most common vitamin A carotenoid in foods and dietary supplements is beta-carotene.

    Why do I need vitamin A?

    Vitamin A is essential for vision and maintaining the conjunctival membranes, cornea and rhodopsin (a protein that absorbs light) in the eyes.

    Vitamin A plays an important role in supporting cell growth and differentiation in the heart, lungs, digestive system and kidneys.

    Vitamin A is also involved in maintaining a healthy immune system.

    How much vitamin A do I need?

    The recommended daily allowance (RDA) of vitamin A for men aged between 19 and 50 years is 900mcg and women 700mcg a day.

    The RDA of vitamin A for pregnant women aged between 14 and 18 years is 750mcg a day, increasing to 1200mcg a day during lactation.

    The RDA of vitamin A for pregnant women aged between 19 and 50 years is 770mcg a day, increasing to 1300mcg a day during lactation.

    The daily RDA of vitamin A for babies and children is as follows:

    • Babies aged 0-6 months: 400mcg
    • 7-12 months: 500mcg
    • 1-3 years: 300mcg
    • 4-8 years: 400mcg
    • 9-13 years: 600mcg
    • 14 and 18 years: 700mcg a day for girls and 900mcg for boys

      The Department of Health recommends that men have no more 0.7 mg a day and women no more than 0.6 mg a day of vitamin A.

      The Department of Health also recommends that pregnant women or those who are trying to conceive should not take vitamin A supplements or eat foods rich in vitamin A, such as liver or liver-based products.

      What happens if I don't have enough vitamin A?

      Vitamin A deficiency (VAD) is caused by inadequate levels of vitamin A. It is extremely rare in the UK.

      The three groups of people most commonly affected by VAD are:

        Premature infants

        Premature infants have insufficient stores of vitamin A when they are born and the level of vitamin A in their blood usually remains low throughout the first year of life.

        Premature babies with VAD are at a greater risk of eye, gastrointestinal and chronic lung disorders.

        Cystic fibrosis

        Many people with cystic fibrosis also have pancreatic insufficiency, which leaves them unable to absorb fat. This leads to VAD.

        Pancreatic replacement treatment, caloric supplements and a good nutritional plan is usually successful in improving the levels of vitamin A in people with cystic fibrosis.

        Children and pregnant or breastfeeding women in developing countries

        The World Health Organisation estimates 190 million pre-school-aged children and 19.1 million pregnant women to be deficient in vitamin A around the world.

        Most of these cases occur in developing countries, where people have limited access to food containing vitamin A or cannot afford it.

        Pregnant women require more vitamin A than women who are not pregnant to support the growth of their baby and their own metabolism.

        Pregnant or lactating women who have VAD are at an increased risk of maternal and infant morbidity and mortality, anaemia and slow infant development.

        Women with VAD who breastfeed their infants are unlikely to have optimal levels of vitamin A in their breast milk.

        Therefore, their children will not be able to maintain adequate vitamin A stores. The most common complication arising from VAD in such children is xerophthalmia.


        Xerophthalmia is an eye disease that can weaken the immune system.

        It increases the risk of measles and diarrhoea.

        The symptoms of xerophthalmia include night blindness, Bitot's spots, corneal xerosis and keratomalacia.

        The earliest symptom of xerophthalmia is night blindness – inability to see in low light or darkness.

        Where is vitamin A found?

        Vitamin A is found in the following foods:

        • liver
        • whole milk
        • cheese
        • butter, margarine and reduced fat spreads
        • carrots
        • dark green, leafy vegetables
        • orange-coloured fruits, eg apricots and mangoes

          What are the effects of cooking on vitamin A?

          Food preparation reduces the amount of nutrients in a particular food.

          In most cases, processes that expose foods to heat, light or oxygen cause the most nutrient loss.

          Compared to raw foods, freezing foods that contain vitamin A causes a five per cent vitamin A loss, while reheating causes a 10 per cent loss.

          Cooking foods containing vitamin A causes a 25 per cent loss; and washing and draining leads to a 35 per cent loss.

          Drying causes the highest loss of vitamin A, at 50 per cent.

          It is important to wash all fruit and vegetables before cooking to remove microorganisms on the surface.

          Meat should be thoroughly cooked before eating.

          Do I need to take vitamin A supplement?

          Vitamin A is available both as a standalone supplement and as part of a multivitamin.

          The vitamin A in some supplements is comprised of both beta-carotene and preformed vitamin A, while others contain only preformed vitamin A or beta-carotene. The packaging label should specify this.

          The Department of Health advises that the amount of vitamin A in a varied and balanced diet should be sufficient.

          However, if you do decide to take a supplement, make sure that your total daily intake of vitamin A from food and supplements does not exceed 1.5 mg.

          Do not take vitamin A supplements (unless advised to by a doctor) or eat liver if you are pregnant or trying to conceive.

          Do not eat liver or liver-based products more than once a week, as they are high in vitamin A.

          Do not eat liver or take more than 1.5 mg of vitamin A a day (this includes fish oil) if you are a woman who has been through the menopause or you are an older man.

          If you do eat liver once a week, do not take more than 1.5 mg of any supplement containing vitamin A a day.

          In summary, it is safe to avoid taking more than 1.5mg a day of vitamin A either in supplement or dietary form.

          What are the side effects and safety precautions of taking a vitamin A supplement?

          The Department of Health does not recommend that pregnant or breastfeeding women take vitamin A supplements or eat foods rich in vitamin A, such as liver or liver-based products.

          Excessive alcohol may enhance the potentially harmful effect of vitamin A on the liver.

          People with a condition called Type V hyperlipoproteinemia should not take vitamin A supplements as it may lead to hypervitaminosis A (excessive levels of vitamin A).

          People with liver disease should not take vitamin A supplements as it may lead to liver toxicity and intrahepatic cholestasis – which stops the flow of bile from the liver to the intestines.

          Bile is a dark green/yellow-brown substance produced by the liver to aid digestion.

          What happens if I take too much vitamin A?

          Vitamin A is a fat-soluble vitamin, which means that the body uses the amount of vitamin A it needs, then stores the rest.

          However, in cases of high intake of vitamin A, it can accumulate and lead to hypervitaminosis A.

          This causes increased intracranial pressure, dizziness, headache, nausea, joint and bone pain, skin irritation, coma and death.

          Hypervitaminosis A during pregnancy can cause congenital birth defects, including malformations of the eye, skull, lungs and heart.

          Women who are pregnant are not advised to take high doses of vitamin supplements.

          Some research suggests that having over 1.5 mg of vitamin A a day may damage bone health over many years, making bones more susceptible to fracture.

          There is also evidence to suggest that taking beta-carotene supplements is associated in an increased risk of lung cancer in smokers and people heavily exposed to asbestos.

          Although this link has not been confirmed, it is recommended that people who smoke or those with a known exposure to asbestos do not take beta-carotene supplements.

          Do vitamin A supplements have any drug interactions?

          Vitamin A interacts with the following medications:

            Want to know more about vitamins and minerals?

            Vitamin A: Vitamin A can be found in carrots and green, leafy vegetables.

            Vitamin B3: Eggs are a good source of vitamin B3 as well as protein.

            Vitamin B2: Women who take oral contraception may benefit from vitamin B2 supplementation.

            Vitamin B5: Using fresh food while cooking helps to preserve vitamins.

            Vitamin B6: Vitamin B6 is involved in maintaing a healthy level of homocysteine, which decreases risk of heart disease.

            Vitamin B7: Vitamin B7 deficiency can be caused be eating raw egg whites over many years.

            Vitamin B9: Brown rice, green vegetables and fortified breakfast cereals are good sources of vitamin B9.

            Vitamin C: Citrus fruits are a good source of vitamin C.

            Vitamin D: Individuals with low vitamin D levels are at risk of developing health problems linked to vitamin D deficiency, such as osteomalacia.

            Vitamin E: Vitamin E is one of four lipid-soluble vitamins (vitamin A, D and K).

            Vitamin K: Your baby should receive a vitamin K injection or drops soon after birth.

            Calcium: The recommended daily allowance (RDA) of calcium in the UK is 700mg a day for adults and pregnant women.

            Iron: Iron is involved in energy metabolism and the metabolism of drugs and foreign substances being removed by the body.

            Magnesium: A low level of magnesium in the blood is common in people who are severely ill, alcoholics and those with malabsorption disorders.

            Phosphorus: Phosphorus is a mineral required by the body. It is the second most abundant mineral in the body.

            Sodium: Sodium makes up sodium chloride - otherwise known as salt.

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