RDIs and Food Sources – Vitamin A

Vitamin A is a fat-soluble vitamin that occurs in two forms:

• Retinol (found in animal foods)
  Retinol is present in liver, milk, cheese and butter.

• Carotenoids (found in plant foods)
  The most common carotenoid is beta-carotene, which gives carrots their orange colour. Carotenoids are also found in dark green leafy vegetables such as spinach and broccoli, as well as yellow and orange fruits and vegetables, including capsicum and kūmara. The body converts carotenoids into vitamin A as required.

 Retinol equivalents

Beta-carotene equivalents

Excessive intake of vitamin A in the form of retinol can be toxic and may increase the risk of liver abnormalities. Although toxicity from food sources is uncommon, it should be considered when taking supplements that contain high levels of retinol.

High intakes of vitamin A (retinol) during pregnancy may increase the risk of birth defects. Women who are pregnant should:

• Avoid eating more than 100 g of liver per week, as liver contains very high levels of retinol.

• Avoid taking cod liver oil.

• Avoid supplements containing vitamin A, including fish oils, unless advised to do so by their doctor or healthcare professional.

Carotenaemia

Carotenaemia is a condition in which the skin develops an orange-yellow colour due to excessive consumption of beta-carotene. The discolouration is most noticeable on the palms of the hands and the soles of the feet.

Unlike jaundice, carotenaemia does not cause yellowing of the whites of the eyes. It is most commonly seen in young children and, despite its striking appearance, is generally harmless and does not usually cause other health problems.

Treatment is straightforward and involves reducing the intake of foods that are particularly high in beta-carotene.