Coeliac disease is a chronic intestinal illness caused by consuming gluten, a mixture of proteins contained in certain grains (wheat, barley, rye, etc.) The illness manifests itself mainly with digestive symptoms (diarrhea, pain, bloating). The name of the illness is derived from the Greek word koiliakós, which means "abdominal." The illness is also often referred to as gluten intolerance or gluten enteropathy.
When people who suffer from the illness ingest gluten, it causes an abnormal immune reaction in the small intestine that results in inflammation and damage to the intestinal walls. More specifically, it is the intestinal villi that are destroyed. These are small, finger-like projections that increase intestinal wall area that is then available for absorbing most nutrients, vitamins, and minerals.
If the inflammation persists, the damaged intestine becomes incapable of absorbing certain nutrients, vitamins, and minerals. Malnutrition can ensue, despite following a normal diet.
Other symptoms of varying intensity such as fatigue, depression, and joint pain can occur, and over time, more serious health problems can also appear.
People suffering from the illness can, however, restore their health by eliminating gluten from their diet.
Intolerance or an allergy?
Though the expression "gluten intolerance" is often used, coeliac disease is not food intolerance because it's caused by an immune system reaction. It is in fact an allergy to gluten.
Nevertheless, unlike classic allergies, the abnormal reaction of the immune system turns against the body as well, by attacking the lining of the small intestine. Coeliac disease is therefore an auto-immune disease caused by the ingestion of gluten.
Reference: www.passeportsanté.net, L’intolérance au gluten (Maladie coeliaque), consulted on 30-04-14