Although people commonly call many reactions to wheat a “wheat allergy,” most reactions actually represent something else.
Gastrointestinal distress is more likely, for example, to be due to lectins (wheat germ agglutinin) in wheat that disable the normal capacity to keep foreign substances from gaining entry into the bloodstream. Or it may be due to the gliadins, the same proteins that amp up appetite, cloud your thinking, yield addictive behavior and generate the wheat withdrawal syndrome. Cramps, diarrhea, and acid reflux likely have nothing to do with an allergic response.
Joint pain likewise is more likely due to gliadin and/or glutens, proteins that have potent capacity to activate inflammation. Joint inflammation is also encouraged by lectins, since the foreign proteins allowed entry into your body may trigger autoimmune responses to joint structures. No allergy here either.
So is there really such a thing as “wheat allergy”?
Yes, there is indeed. Wheat allergy is an immune response that involves the IgE class of antibodies that trigger mast cells (a form of white blood cell) to release histamine, yielding the familiar itchy runny nose, airway spasm (asthma), sinus congestion, and skin rashes, especially hives (urticaria) and atopic dermatitis. Wheat components can also induce anaphylaxis, or shock and collapse; this is called wheat-dependent exercise-induced analyphylaxis, or WDEIA, nearly always induced, oddly, by exercising after consuming something containing wheat.
What components of wheat are potentially responsible for allergic IgE responses? There are many, including:
Acyl CoA oxidase
Alpha- and beta-amylases
Alpha amylase inhibitors
Lipid transfer protein (a very interesting recent addition to the list, with plenty more to learn)
Serine proteinase inhibitors (serpins)
(Reviewed here, for anyone interested.)
Wheat allergy, of course, has increased explosively in children, along with allergy to corn, soy, peanuts, dairy, and eggs. (Author of The UNHealthy Truth and mother, Robyn O’Brien, a champion for understanding food allergies in kids, provides this excellent overview during a recent TED presentation.) In these kids, wheat may simply be another source of unique allergens previously unseen by humans, i.e., perhaps some of the above proteins altered by just a few amino acids. Are kids serving as the “canary in the coal mine,” reacting to unique proteins generated by the manipulations of agricultural geneticists and agribusiness? I think they are. These kinds of allergies that kids have are uncommon in adults. But what is the consequence of all of us exposed to these foreign proteins that, while they may not provoke allergy, have not been previously consumed by humans? We’re likely to find out in the coming years in those who continue to consume this product of genetics research called “wheat.”
So, yes, genuine wheat allergy does occur. But, in the true sense of the term “allergy,” it is probably responsible for only some of the responses we see with wheat consumption.