No clear evidence exists to support the idea that celiac
disease is increasing in prevalence because farmers are growing strains of
wheat that contain more gluten.
Donald D. Kasarda cites evidence that the incidence of
celiac disease increased during the second half of the 20th century. Some
estimates indicate that the disease is 4 times more common today. Also known as
gluten intolerance, celiac disease occurs when gluten, a protein in wheat,
barley and rye, damages the lining of the small intestine, causing a variety of
symptoms. Nobody knows why the disease is increasing. One leading explanation
suggests that it results from wheat breeding that led to production of wheat
varieties containing higher levels of gluten.
Kasarda’s Perspective article examined the scientific
evidence for that hypothesis and found that gluten levels in various varieties
have changed little on average since the 1920s. Overall gluten consumption,
however, 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 their characteristics, such as 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.
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