There are some people who have a condition in which the lining of the intestine is damaged by gluten; this is known as coeliac disease. This damage inter feres with the normal absorption of nutrients from digested foods and can lead to an illness that resembles general malnutrition.

Coeliac disease is controlled by excluding gluten from the diet. This means avoiding foods containing wheat, rye, and barley. The position of oats is controversial but some people who suffer from coeliac disease also have a sensitivity to oats. If you have coeliac disease you must strictly adhere to the gluten-free diet, and it is usually necessary to continue for life. Good dietary guidance is essential, as wheat flour is 'hidden' in many convenience foods, in which it is used as a filler. There are gluten-free goods available, as well as specially prepared gluten-free products, such as bread, biscuits and cake.