Gluten, the protein found in wheat, barley, rye, and other select grains, has become an increasingly unwelcome guest at the table in recent decades. And it's not just because of a "made-up allergy that you invented to get attention," as a skit on Saturday Night Live purported.

Three million Americans, about one percent of the population, suffer from an autoimmune disorder called celiac disease. In people with celiac disease, even the smallest trace of gluten can trigger the production of antibodies that damage the lining of the small intestine. The condition poses a host of health risks including osteoporosis, infertility, and intestinal cancers.

Until last Friday, no standard definition for the term "gluten-free" existed—even though the market for gluten-free food