Could wheat allergy play a role in diabetes development?

By Stephen Daniells,

An abnormal response to wheat proteins may tip a person’s delicately poised immune system into developing type-1 diabetes, suggests a study from Canada.

Writing in the journal Diabetes, researchers from the Ottawa Hospital Research Institute and the University of Ottawa report that almost half of the 42 type-1 diabetics tested in their study had an abnormal immune response to wheat proteins.

“The presence of an [immune response] to [wheat proteins] in a subset of patients indicates a diabetes-related inflammatory state in the gut immune tissues associated with defective oral tolerance and possibly gut barrier dysfunction,” wrote the researchers, led by Dr. Fraser Scott.

Type-1 diabetes occurs when people are not able to produce any insulin after the cells in the pancreas have been damaged, thought to be an autoimmune response. The immune system is thought to mistakenly attack the pancreas, the organ that regulates blood sugar. The disease is most common among people of European descent, with around two million Europeans and North Americans affected.

In addition, the incidence of the disease is on the rise at about three per cent per year, according to a study published last year in the Archives of Disease in Childhood. The number of new cases is estimated to rise 40 per cent between 2000 and 2010.

“The immune system has to find the perfect balance to defend the body against foreign invaders without hurting itself or over-reacting to the environment and this can be particularly challenging in the gut, where there is an abundance of food and bacteria,” said Dr Scott.

“Our research suggests that people with certain genes may be more likely to develop an over-reaction to wheat and possibly other foods in the gut and this may tip the balance with the immune system and make the body more likely to develop other immune problems, such as type-1 diabetes.”

With a growing number of people suffering from coeliac disease, the food industry is already producing more wheat-free foods, adding to the burgeoning ‘free-from’ market, which has been enjoying sales growth of over 300 per cent in the UK since 2000, according to market analyst Mintel.

Dr Scott and his team recruited 42 people with type 1 diabetes and found that immune cells called T cells from people with type-1 diabetes are also more likely to over-react to wheat. The research also reports that this over-reaction is linked to genes associated with type-1 diabetes.

In an accompanying editorial in the same journal, Dr Mikael Knip from the University of Helsinki, Finland said: “These observations add to the accumulating concept that the gut is an active player in the diabetes disease process.”

Benefits of wheat-free

Earlier results from animal studies by Dr Scott indicated that a wheat-free diet can reduce the risk of developing diabetes. However, the researcher stated that more research will be required to confirm the link and determine possible effects of diet changes in humans. Research is also needed to investigate links with coeliac disease, another autoimmune disease that has been linked to wheat.

Source: Diabetes
August 2009, Volume 58, Pages 1789-1796, doi:10.2337/db08-1579
"Diabetes-Specific HLA-DR–Restricted Proinflammatory T-Cell Response to Wheat Polypeptides in Tissue Transglutaminase Antibody–Negative Patients With Type 1 Diabetes"
Authors: M. Mojibian, H. Chakir, D.E. Lefebvre, J.A. Crookshank, B. Sonier, E. Keely, F.W. Scott