If you are gluten sensitive watch where you eat and what you order.
More than 800 investigators tested more than five thousand food items in restaurants in the United States over a year and a half, finding about one-third of "gluten-free" foods actually contained trace levels of the substance.
While the study wasn't designed to find out how the gluten showed up in these foods, the team believes cross contamination may be to blame.
Gluten is a protein in wheat and other grains that can't be ingested by people with celiac disease because it can damage the intestines.
The Food and Drug Administration regulates packaged foods with gluten-free labeling, but there is no federal oversight of gluten-free claims in restaurants.
The study is scheduled for presentation during the meeting of the American College of Gastroenterology, in Philadelphia.
Research presented at medical meetings should be considered preliminary until it appears in a peer reviewed medical journal.