MINNEAPOLIS (WCCO) — Nearly 2 million Americans have celiac disease and should avoid eating gluten, a new study finds.

However, as little as a decade ago, virtually no one in the U.S. seemed to have a problem eating the protein that’s found in bread and other foods.

Does the national uptick in people eating gluten-free foods suggest a celiac disease epidemic? Or are people unnecessarily turning to the diet as a food fad?

According to a new study from the Mayo Clinic, it may be both.

The study found most people with celiac disease don’t know they have it, and many people eating gluten-free don’t have celiac disease.

Celiac disease is a condition that damages the lining of the small intestine when a person eats gluten found in wheat, barley, rye or some oats. It prevents the intestine from absorbing necessary nutrients.

Dr. Joseph Murray of the Mayo Clinic found that Celiac disease is increasing, and it is four times more common now than it was 50 years ago.

“More people are aware of it because there’s more testing. But there’s also been a dramatic increase in people who have the disease. It must be something environmental,” said Murray. “What that factor is that could drive celiac disease isn’t clear. But we know for celiac disease you have to eat wheat, barely or rye. The prime suspect is — has something changed with regard to wheat?”

Right now, about 1.8 million Americans have been diagnosed with celiac disease, but about 1.4 million people may not be aware they even have it. On the flip side, about 1.6 million people in the U.S. are on a gluten-free diet even though they haven’t been diagnosed with celiac disease.

Why does Murray think people who don’t have celiac disease are eating gluten free?

“While we didn’t examine that in this study, experience suggests that people try gluten free for many reasons. Some people feel better. Other people think they will lose weight,” he said.

Murray said that eating gluten free doesn’t necessarily mean you’ll lose weight. He suspects that those eating gluten-free who don’t have celiac disease are most likely just eating less in general.

As to whether it’s harmful to eat gluten free if you don’t have celiac disease, Murray says you may miss out on certain vitamins and things like fiber, which you need. It takes more work to get a nutritionally complete diet if you’re skipping foods with gluten.