A new study has found that about 32 percent of restaurants serving gluten-free menu may be untrue to the promise, making people with celiac disease vulnerable.

The study reported that there is still a higher chance of being served with gluten food even when the menu indicates it is gluten-free.

Eating Out Can Be Dangerous

Dr. Benjamin Lebwohl, the Herbert Irving assistant professor of medicine and epidemiology at the Columbia Mailman School of Public Health, said that eating in restaurants may be troublesome to people with celiac disease. About one-third of the foods served in restaurants, which are labeled gluten-free tested positive for gluten content.

More than 50 percent of gluten-free pizza and pasta dishes from the surveyed restaurants had presence of gluten.

"Patients have long suspected that gluten contamination in restaurant foods is a frequent occurrence, and these results support that," said Lebwohl. "Our findings suggest that pizza, pasta and foods served at dinner were more likely to have a problem."

Gluten Sensor

Restaurant patrons tested their food for gluten content using the Nima Gluten Sensor. Only a pea-size of each food item is required to run the test.

A total of 804 users conducted 5,624 gluten tests for over 18 months. Gluten was found in 27 percent of breakfasts, 29 percent of lunches, and 34 percent of dinners. Restaurants in the western part of the United States were likely to test positive for gluten than those in the Northeast.

The U.S. Food and Drug Administration said that food items should have less than 20 parts per million of gluten for it to be considered gluten-free. The Celiac Disease Foundation said that the evidence pointed to the challenges of maintaining a strict, gluten-free diet.

"If you have celiac disease or it's harmful for you to ingest gluten, you should feel comfortable asking the waiter how things are prepared," said lead author Dr. Benjamin Lerner.

Details of the study was published in the American Journal of Gastroenterology.