LA CROSSE, Wis. -- Do you know someone trying out the latest food fad? That would be the gluten-free diet.

However, for some, it's actually a recommended treatment for what researchers say is an underdiagnosed disease: celiac disease.

"Simplistically, it's an allergic reaction to a protein in certain grains," explained Dr. Sandra Cepoi, who works at the Mayo Clinic Health System in La Crosse.

Cepoi says symptoms of celiac disease include bloating, stomach pain, and diarrhea. She says many people are self-diagnosing as they learn more about the disease.

"I think most times it's better to confirm with a professional," she said.

Doctors are finding more people have the disease than previously thought. Researchers at Mayo Clinic in Rochester estimate there are about 1.4 million undiagnosed cases in the country. That means about 1 in every 100 people have the disease.

The new research comes at the same time more people are trying out gluten-free diets.

In just the last few years, the gluten-free section at many grocery stores has gone from just a few items to almost a whole aisle.

"Everyday there are new products coming out," said Kayla Kolbe, the natural foods manager at the Festival Foods in Onalaska.

Kolbe says the growing interest from shoppers is because companies are coming out with more gluten-free options.

"It's amazing the things they've come up with...gluten-free mozzarella sticks, pita chips...you know, things that were kind of off-limits before to people with celiac disease," said Kolbe.

Many of the gluten-free products will taste different and often do cost more money.

Doctors say even those who do not have celiac disease can go on a gluten-free diet without side effects.