What is Gluten?

In terms of the medical definition of Celiac Disease, or Gluten Intolerance, "gluten" is defined as the mixture of many protein fragments (called peptide chains or polypeptides) found in common cereal grains — wheat, rye, barley and sometimes oats (oats don’t naturally contain gluten, but are often subject to contamination with small amounts). Wheat is the only grain considered to contain true "gluten" and the peptides that predominate in wheat gluten are gliadin and glutenin. Gliadin is thought to be the peptide chain that instigates the toxic immune response and subsequent intestinal damage in celiacs. However, other protein fragments thought to be toxic to celiacs occur in rye, barley, and oats. They are secalins, hordeins, and avenins, respectively. Even though some research suggests that the avenins are not toxic, most celiacs still avoid oats just to be safe. Minute amounts of any of these protein fragments can cause intestinal damage in people with celiac disease. Because the disease is not fully understood, it is thought there may be other peptide chains including some derived from glutenin, that are also toxic. Because of the lack of definitive research on the disease, celiacs must often live by the saying, "when in doubt, leave it out."