What causes coeliac disease?
Gluten and a substance related to gluten called gliadin are heavy proteins. They are found particularly in wheat and rye and to a lesser extent, in barley and oats. These proteins are harmful to people who have coeliac disease.
What triggers coeliac disease?
The exact mechanism of this effect is not known, but two alternative theories have been proposed to explain how this harm comes about: the toxic theory and the immune theory.
The toxic theory explained:
According to the toxic theory, people with coeliac disease lack a particular enzyme normally found on the mucous membranes (mucosa) which line the small intestine. The function of this enzyme is to break gluten and gliadin down into smaller particles which are then able to pass through the wall of the intestine into the bloodstream.
So, according to this theory, if a person with coeliac disease eats food containing gluten and gliadin, the lack of this enzyme will lead to an accumulation of gluten and gliadin on the mucous membranes of the small intestine. It is suggested that this accumulated gluten and gliadin has a toxic effect on the mucosa.
The immune theory explained:
Alternatively, the immune theory claims that gluten or the breakdown products of gluten (metabolites) start an immunological reaction in the mucosa of the small intestine, which causes structural abnormalities to develop in the mucosa. Evidence for this is not clear.
The symptoms of coeliac disease
How to diagnose coeliac disease
How coeliac disease can be treated
Reviewed by Dr Ismail Moola MBCHB (UCT) FCP (SA) Cert Gastro Phys (SA).
Specialist Physician / Gastroenterologist Netcare Sunninghill Hospital and part time Lecturer Department of Internal Medicine, Division of Gastroenterology, Wits University.
Previously reviewed by Dr G Watermeyer MBChBFCP (SA), Cert Gastroenterology (SA), Consultant GIT Clinic Groote Schuur Hospital.