Vitamin A

Vitamin A is a fat-soluble vitamin that the body stores in the liver. It sits at the centre of several systems. In the eye, it is the active part of rhodopsin, the molecule in the retina that lets the eye work in low light; long-running vitamin A deficiency was the historical cause of "night blindness" and remains the leading preventable cause of childhood blindness globally. In the immune system, vitamin A helps maintain the barriers that block infection (skin, gut lining, airway lining) and supports the immune cells themselves. In growing children, it supports normal growth.

Two forms of vitamin A reach the body from food. Retinol (and its esters) is the pre-formed vitamin found in animal foods: liver carries enormous amounts, dairy fat and egg yolks carry modest amounts, oily fish carries some. Beta-carotene (and a few related carotenoids) is the pro-vitamin found in orange, yellow, and dark green vegetables: sweet potato, carrot, butternut squash, spinach, kale. The body converts beta-carotene to retinol at a rate that depends on intake; conversion is regulated and excess beta-carotene from food does not cause vitamin A toxicity, only a slight orange tinge to the skin at very high intakes (which fades when intake drops).

Why retinol matters in pregnancy: retinol at very high intakes is teratogenic, meaning it can cause birth defects. Beta-carotene does not have this effect, because the body controls how much it converts to retinol. This is why the NHS distinguishes the two in pregnancy advice: orange and green vegetables are fine; liver and high-dose retinol supplements are not.

Pregnancy note: if you are pregnant, planning a pregnancy, or could become pregnant, do not eat liver or liver products (such as pâté), and avoid taking supplements that contain vitamin A unless advised by your GP. Vegetables that contain beta-carotene (carrots, sweet potato, spinach, kale, butternut squash) are safe and beneficial in pregnancy.

Values per 100g come from USDA SR Legacy and McCance and Widdowson 7th edition; the site's food entries currently store macros only. The vitamin A figures are expressed as retinol equivalents (RE), the UK convention. For comparison, the EU and US use retinol activity equivalents (RAE), a slightly different scale.

The headline number on liver is real: a single 100g portion of lamb's liver delivers around 15,000 micrograms of vitamin A, more than 20 times the men's RNI. NHS standing advice on liver, even for non-pregnant adults, is not to eat it more than once a week because of the high vitamin A content. Pregnant women are advised to avoid it entirely.

UK Reference Nutrient Intake (RNI) for vitamin A is set by SACN (1991 Dietary Reference Values), expressed as retinol equivalents.

Vitamin A deficiency is uncommon in the UK because retinol and beta-carotene are both widely present in the food supply. It does still occur in people with very narrow diets, malabsorption conditions, or after gastric surgery, and in very young children with severely restricted diets.

Signs of deficiency:

• Night blindness: difficulty seeing in low light, the earliest and most specific sign
• Dry, gritty eyes (xerophthalmia in severe cases)
• Dry, rough skin
• More frequent or severe infections (respiratory, gut)
• In children: slowed growth, immune problems, in severe cases corneal damage

Who is at higher risk in the UK

• People with cystic fibrosis, coeliac disease, or other fat malabsorption conditions. Vitamin A is fat-soluble; absorption falls when fat absorption is impaired.
• People after bariatric surgery, particularly procedures that bypass parts of the small bowel.
• People with very narrow diets: little fruit or veg, and limited dairy or eggs.
• Severe alcohol use, which depletes liver stores and affects absorption.
• Premature babies and severely undernourished young children.

If symptoms or a risk factor are present, a GP can arrange a blood test for vitamin A. Confirmed deficiency is treated with supplementation at a dose set by the clinician.

Vitamin A is the supplement where chronic excess is well-documented, particularly from retinol and fish liver oils. Beta-carotene from vegetables does not cause toxicity at any normal intake.

NHS guidance: having more than an average of 1.5mg (1,500 micrograms) of vitamin A a day across many years may make your bones more likely to fracture as you get older. People who eat liver or liver pâté once a week may be having more than this on average. NHS advice is to cut down or avoid liver if eating it weekly.

Symptoms of chronic excess (typically from supplements or repeated liver intake):

• Headaches
• Dizziness
• Blurred vision
• Nausea, vomiting
• Skin changes, hair loss
• Liver enzyme abnormalities
• In long-term excess: bone weakening, joint pain, and increased fracture risk in older adults

The pregnancy caution, restated: if you are pregnant, planning a pregnancy, or could become pregnant, avoid taking supplements containing vitamin A, including fish liver oil, unless advised to by your GP. Also avoid liver or liver products, such as pâté, because these are very high in vitamin A.

This caution is specifically about retinol. Eating carrots, sweet potato, butternut squash, spinach, kale, and other beta-carotene-rich vegetables in pregnancy is positive and recommended.

Vitamin A supplementation is not routinely needed for healthy UK adults eating any mix of vegetables, eggs, and dairy.

Supplements during pregnancy (NHS standing advice)

If you are pregnant, planning a pregnancy, or could become pregnant, avoid supplements containing vitamin A, including fish liver oil, unless your GP has specifically advised them. Standard pregnancy multivitamin products sold in UK pharmacies are formulated to be safe in pregnancy and either omit retinol or use beta-carotene only; always check the label.

The NHS Healthy Start vitamins for women contain vitamin C, vitamin D, and folic acid, and do not contain vitamin A.

The Healthy Start vitamin drops for children aged 6 months to 4 years contain vitamins A, C, and D, in age-appropriate amounts. This is the recommended route for child supplementation rather than adult-format products.

Adults and liver

Eating liver more than once a week regularly contributes more retinol than the body needs. NHS advice is to cut down or avoid liver in this pattern, particularly for postmenopausal women whose bones are already being protected against accelerated loss.

When supplementation is indicated

• Confirmed deficiency, treated by a GP or dietitian.
• Cystic fibrosis, some absorption conditions: as part of routine care, on personalised advice.
• Healthy Start vitamins for qualifying children aged 6 months to 4 years.

• Vitamin A as a food colour: E160a beta-carotene is the form used as an orange-yellow food colour.
• Fat-soluble vitamins together: Vitamin D, Vitamin E, Vitamin K.
• UK official position on fruit and veg: The Eatwell Guide.
• Best food sources: Sweet potato, Carrots, Butternut squash, Spinach, Kale, Cheddar, Eggs.

• NHS. Vitamins and minerals: Vitamin A. nhs.uk/conditions/vitamins-and-minerals/vitamin-a-retinol. Adult RNI, pregnancy and liver caution, upper level.
• NHS. Foods to avoid in pregnancy. Liver and liver products section.
• SACN. Dietary Reference Values for Food Energy and Nutrients for the United Kingdom. Department of Health Report 41 (1991). Source of the age-banded RNIs.
• NHS. Healthy Start scheme.
• Public Health England. McCance and Widdowson's The Composition of Foods, 7th summary edition (2015).

This page is reference information for UK shoppers. It is not medical advice. Pregnancy supplement decisions, including any vitamin A-containing product, should be discussed with a GP or midwife.