The proteins that cause allergic reactions in some children to foods such as eggs and milk might also hold the key for kids to build a tolerance to those foods.
Using a mouse model predisposed to egg allergies, University of Guelph food scientist Yoshinori Mine has found that animals would become desensitized to the allergy-causing protein after eating just a portion of it.
“By ingesting only the peptides and not the whole protein, the body suppresses the urge to react,” Mine said in a release Monday. “After repeated exposure, the body learns to accept the protein instead of trying to defend itself against it.”
Next on the agenda is to get the technique into human clinical trials and work out a way the peptide can be administered orally, Mine said.
That means finding a way to incorporate the peptide into foods such as cookies so it will be appealing to young children, he said.
Six to eight per cent of children in North America have some type of food allergy, most commonly to milk, eggs or nuts, the university said.
Currently, doctors tell the parents to remove the offending foods from the diet of a susceptible child, Mine said, “but removing foods like eggs and milk can be nearly impossible.”
Children are more susceptible to developing allergies because their gut immune systems are still developing and can’t digest the problem proteins, which move into the bloodstream — where the body reacts by cranking up its defenses, creating allergic reactions.
About 50 per cent of children with food allergies outgrow them by age five.
However, the other 50 per cent can’t develop a tolerance on their own, Mine said, and science doesn’t yet know why some do but others don’t.
Mine’s study, published recently in the British journal Clinical and Experimental Allergy, used mice that react with allergy symptoms ranging from a rash to death from anaphylaxis when fed eggs.
As part of the study, he fed the mice multiple peptides of the egg protein that spurs allergic reactions. After six weeks, the mice would then ingest the whole protein, much like a child would when eating eggs.
Mine then monitored the mice for visible signs of an allergic reaction and also took blood and tissue samples to test their histamine and immunoglobulin E, compounds the body produces to induce allergic reactions.
Mine’s study found 80 per cent of the mice didn’t react. The other 20 per cent showed only “a mild allergic reaction,” the university said.
“When ingested, the multiple peptides help stimulate the body to make T-suppressor lymphocytes specific for allergen suppression,” Mine said. These lymphocytes in turn “retrain the body not to react to allergic substances.”
Mine said he also aims to develop the approach so it can be applied to other common foods such as milk and nuts that are known to cause allergic reactions in the very young.