There’s a good chance that the gluten-free fettuccine alfredo you ordered may come with a side of gluten. 32% of restaurant foods labeled gluten-free contain more than trace amounts of gluten, according to a new study published in the American Journal of Gastroenterology.
Dr. Benjamin Lebwohl and his team made this discovery by analyzing data uploaded by users of the portable device Nima Gluten Sensor, which is used by gluten-sensitive diners to test food before they eat it. The manufacturer provided 5,624 food tests by 804 users over 18 months. To be labeled gluten-free in the U.S., a product must contain less than 20 parts per million of gluten, so even if the devices detected some gluten in some foods, they weren’t necessarily unsafe for people with celiac disease or gluten intolerance. Still, 32% is high.
Perhaps unsurprisingly, the researchers found that the biggest culprits were the foods that are traditionally chock-full of gluten. Gluten-free pasta samples were positive in 51% of tests and gluten-free pizza contained gluten in 53% of the tests. Going gluten-free at breakfast was slightly easier than at lunch or dinner; researchers detected gluten in 27% of supposedly gluten-free breakfast foods versus 29% of lunch items tested and 34% of gluten-free dinner options. While the researchers didn’t call out any restaurants by name, they report that fast food restaurants had the highest level of gluten in their gluten-free foods compared to casual and fast casual restaurants.
Interestingly, gluten-free restaurant foods were less likely to test positive for gluten in the western part of the U.S. than in the Northeast (perhaps due to Californians’ greater awareness of special diet needs?). In a statement about the study, Lebwohl noted that lack of awareness may be at fault for the gluten contamination and “the solution may be better education for food preparers.”