The Food and Drug Administration explained that a new regulation regarding “gluten-free” foods is aimed at helping in the voluntary labeling of food products. Three million Americans have celiac disease. People with celiac disease have to avoid eating foods containing gluten, otherwise the lining of the small intestine becomes damaged, affecting the proper absorption of vital nutrients into the bloodstream. For a food to be labeled as gluten-free, it must contain no more than 20 parts per million (ppm) of gluten. Patients with celiac disease can tolerate this trace amount without experiencing adverse health effects.
Food and Drug Administration, August 2013