Celiac disease is not controversial, some people have always had it. But belief that it is on the rise - some claims are that the disease is four times more common today - rather than being diagnosed better, is controversial. And there is confusion created by marketing people who want to increase awareness of their products for dietary fashion reasons.
But one claim by concerned consumers merited scientific curiosity: that if there was an increase in celiac disease it may be caused by farmers growing strains of wheat that contain more gluten.
Celiac disease occurs when gluten, a protein in wheat, barley and rye, damages the lining of the small intestine, causing a variety of symptoms. If we don't accept that the disease is better diagnosed and is instead increasing, then there must be a reason why. One popular explanation among the gluten-free community is that wheat breeding led to production of wheat varieties containing higher levels of gluten.
Yet there is no real evidence for that claim, according to a study in the Journal of Agricultural and Food Chemistry.
Donald D. Kasarda's Perspective article examined the scientific evidence for the hypothesis and found that gluten levels in various varieties of wheat have actually changed little since the 1920s.
But gluten consumption has increased due to other factors, one involves increased consumption of a food additive termed "vital gluten," which has tripled since 1977. Vital gluten is a food additive made from wheat flour, and it is added to various food products to improve characteristics like texture.
Overall consumption of wheat flour also has increased, so that people in 2000 consumed 2.9 pounds more gluten annually than in 1970, nearly a 25 percent increase.