Gluten is the main group of proteins in grains and consists of prolamins (in wheat: gliadin) and glutelins (in wheat: glutenins) occurring in the same ratio.  Due to its physicochemical characteristics, gluten is used in food products as a binder.  Coeliac disease is an autoimmune disorder of the small intestine.  It is caused by a reaction to gliadin and the only effective treatment is a lifelong gluten-free diet.  Due to Codex Standard 118-1979, “gluten-free” products must comply with gluten levels (including prolamin fractions from wheat, rye, barley and oats) below 20 mg/kg and “foods specially processed to reduce gluten content” must comply with levels between 20 and 100 mg/kg.