Celiac Disease

What it is
A disorder characterized by an allergic reaction to gluten - a protein found in wheat, barley and rye. When a person with celiac disease eats gluten, the immune system responds by damaging the lining of the small intestine.

When this happens, the body is unable to absorb nutrients into the bloodstream. There are also long-term risks, such as other autoimmune diseases and, rarely, lymphoma.

Symptoms
Can vary greatly -- some people might experience gas, bloating, diarrhea and abdominal pain after eating gluten, while some experience almost no symptoms.

Who gets it
At least 3 million Americans.

Treatment
The most effective treatment is to avoid foods containing wheat, rye and barley -- and follow a "gluten-free" diet. While this may seem daunting, people with celiac disease can eat a well-balanced diet that includes a variety of foods. Many grocery stores now have a gluten-free section.