Beer tested in a new study, including some brands labeled “low-gluten,” contains levels of hordein, the form of gluten present in barley, that could cause symptoms in patients with celiac disease (CD), the autoimmune condition treated with a life-long gluten-free diet, scientists are reporting. The study, which weighs in on a controversy over the gluten content of beer, appears in ACS’ Journal of Proteome Research.
Michelle Colgrave and colleagues explain that celiac disease (CD) affects more than 2 million people worldwide. Gluten, a protein found in foods and beverages made from barley, wheat and rye triggers a reaction in CD patients that affects the small intestine, blocking the absorption of essential nutrients from food. Symptoms vary, but often include diarrhea or constipation, fatigue and abdominal pain. The cause is unknown, and there is no cure. The only treatment is to stay on a life-long gluten-free diet. Barley is used to make beer, but whether the finished product contains gluten is controversial, with some beer companies contending that the brewing process gets rid of gluten or reduces it to very low levels. Existing tests for detecting gluten in malted products are not very accurate. So the scientists developed a highly accurate new test for hordein, the gluten component in barley-based beers.
As expected, their analysis of 60 commercial beers found that eight labeled “gluten-free” did not contain gluten. But many regular, commercial beers had significant levels of gluten. Most surprising, two beers labeled as “low-gluten” had about as much gluten as regular beer.
The authors acknowledge funding from the Australian Coeliac Research Fund.
What is in a Beer? Proteomic Characterization and Relative Quantification of Hordein (Gluten) in Beer.
Michelle L. Colgrave, Hareshwar Goswami, Crispin A. Howitt, and Gregory J. Tanner. J. Proteome Res., October 17, 2011. DOI: 10.1021/pr2008434