Negative outcomes | Plant breeding could extract certain proteins that cause wheat allergies
It’s estimated that one percent of the population has celiac disease, a disorder that can impair the body’s ability to absorb nutrients when gluten is consumed.
The number of people allergic to wheat is unknown, says a United States Department of Agriculture scientist who studies the molecular components of wheat that cause allergic reactions.
“It’s difficult to put numbers together on that and I really haven’t seen any good numbers,” said Susan Altenbach, USDA research biologist.
It’s hard to gauge the percentage of people who have wheat allergies, because it’s tricky for doctors to determine what exactly is causing an allergic response, Altenbach said.
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What is known, however, is that wheat allergies are distinct from celiac disease. A wheat allergy causes a person’s immune system to react abnormally to the proteins in wheat, which causes hives, swelling of the throat and other allergic symptoms.
For people with celiac disease, eating food with gluten can damage the lining of the small intestine,causing diarrhea and malnutrition.
There is a segment of the population that has allergies to wheat or celiac disease, said Gary Fulcher, head of the University of Manitoba food science department. But the bigger problem is the perception that eating wheat leads to negative health outcomes.
Fulcher said some grain has negative qualities, but wheat advocates need to promote the health benefits of whole grains to consumers.
Altenbach isn’t in the business of promoting wheat as part of her work at the USDA Western Regional Research Centre, but is studying ways to make it tolerable for people with allergies.
Specifically, Altenbach wants to eliminate proteins in wheat that cause allergic reactions, but retain desirable genetic traits that produce high quality wheat flour.
Altenbach, who spoke at the Canadian Wheat Symposium in Winnipeg in December, said this type of molecular research is necessary because if wheat allergies become more common, consumption of breads, cereals and other wheat products will decline.
“As you have more and more people that are sensitized to wheat, you have fewer and fewer people that are eating wheat. Maybe the gluten free diet becomes a bigger deal,” she said.
“If you can reduce the number of people that become sensitized to wheat, by reducing the number of these immunogenic proteins in wheat, perhaps there will be a benefit there.”
In 2011, Altenbach published a study on a wheat protein called Omega 5 gliadins that can provoke an allergic response, such as a condition known as wheat dependent exercise induced anaphylaxis. As its name suggests, people with this type of allergy only display symptoms if they exercise shortly after eating wheat.
In her study, Altenbach found it was possible to silence the genes in wheat that trigger the development of omega 5 gliadins, the gluten proteins that cause the allergic response.
That’s a positive step forward but more research is necessary before Altenbach and others can develop a commercial wheat variety without this particular protein.
“We’re eliminating a fairly major gluten protein. So we need to see what the effect of that is, in terms of the functionality of the flour,” she said.
Altenbach said molecular biologists and wheat breeders will continue to study ways to eliminate specific immunogenic proteins found in wheat. Bread labelled “hypoallergenic” is unlikely because there are many proteins in wheat and eliminating all of them may be too complex.
“You’re basically telling people it’s OK, if you have a wheat allergy or sensitivity, you can eat this,” she said.
“You have to know that essentially you have eliminated many proteins, not just certain ones that cause specific types of allergies.”
