Lactose Intolerance

Lactose is a natural sugar found in cow's milk, goat's milk, sheep's milk and other mammalian milks. In order to digest lactose you need to have the enzyme lactase present in the gut. If it is absent you will be lactose intolerant, although tolerance to lactose will vary between individuals. Worldwide lactose intolerance is very common especially in East and South East Asia, Tropical Africa and in Native Americans and Australians where people do not drink milk so their bodies stop producing the enzyme lactase during childhood. Congenital lactase deficiency is very rare but a secondary lactose intolerance can occur in those who have had gut surgery or other damage to the gut (e.g. in newly diagnosed coeliac disease there may be a temporary lactose intolerance).

What foods should be avoided on a lactose free diet?

Obvious sources of lactose like cow's, goat's and sheep's milk as well as yoghurt, fromage frais, butter and margarine, cheese, cream and ice-cream. Milk can also be hidden in ready made products so food labels need to be checked. The following need to be avoided - milk powder, milk solids, buttermilk, cheese powder and cheese flavouring, milk sugar, milk chocolate, whey, whey protein, whey syrup, casein and hydrolysed casein. Lactose can also be present in artificial sweeteners, medicines and vitamin supplements and some tooth-pastes.