The gluten-freak is here!  Celiac is the biggest thing in the food game right now.

Celiac disease (CD) is a genetic disorder. In people with CD, eating certain types of protein, called gluten, sets off an autoimmune response that causes damage to the small intestine. This, in turn, causes the small intestine to lose its ability to absorb the nutrients found in food, leading to malnutrition and a variety of other complications.

The offending protein, gluten, is found in wheat, barley, rye, and to a lesser extent, oats (WBRO). Related proteins are found in triticale, spelt, kamut.

(Celiac Sprue Association)