Apr 8 2019
Benjamin Lebwohl, MD, MS, Celiac Disease Center at NY-Presbyterian Hospital and assistant professor of medicine and epidemiology at Columbia Mailman School, performed a study which found that even trivial quantities of gluten in foods are disturbing for people suffering from celiac disease, and restaurants may be one of the most difficult places to avoid the protein.
Over half of gluten-free pasta and pizza dishes in restaurants tested positive for the presence of gluten; nearly one-third of presumably gluten-free foods included gluten in detectable levels. The study outcomes have been reported in the American Journal of Gastroenterology.
Patients have long suspected that gluten contamination in restaurant foods is a frequent occurrence, and these results support that. Our findings suggest that pizza, pasta and foods served at dinner were more likely to have a problem.
Benjamin Lebwohl, Assistant Professor of Medicine and Epidemiology, Columbia Mailman School of Public Health
Data uploaded by users of Nima Gluten Sensor, a portable device, were used by Lebwohl. Restaurant patrons use this device to test foods. Over a period of 18 months, the manufacturer supplied 5624 food tests by 804 users. The study demonstrated that 32% of tests showed detectable levels of gluten in dishes that ought to have been gluten-free.
In 51% of the tests, gluten-free pasta samples tested positive for gluten. In 53% of the tests, gluten-free pizza included gluten. Gluten was found in 34% of dinners, 29% of lunches, and 27% of breakfasts.
However, Lebwohl stated that there are limitations to the data. “Users may have uploaded results that surprised them the most.” Moreover, the device is highly sensitive. In the United States, for a product to be labeled gluten-free, it should contain less than 20 parts per million.
The device can detect levels as low as 5 to 10 ppm, which most do not consider clinically significant, so a ‘gluten found’ result does not necessarily mean ‘unsafe for celiac disease.’ The device also does not detect certain forms of gluten, such as fermented gluten. So both false positives and false negatives will affect this estimate.
Benjamin Lebwohl, Assistant Professor of Medicine and Epidemiology, Columbia Mailman School of Public Health
Lebwohl suspects that gluten-free foods are contaminated involuntarily, and “the solution may be better education for food preparers.”
The National Institutes of Health (Small Business Innovation, DK105770) and National Institute on Aging (1R01AG049970-01A1) supported the research.