Oat cereals. Celiac disease (coeliac disease) is a permanent intolerance to certain gluten proteins in genetically predisposed people, having a prevalence of about 1% in the developed world. Gluten is present in wheat, barley, rye, oat, and all their species and hybrids and contains hundreds of proteins, with high contents of prolamins. Oat prolamins, named avenins, are similar to gliadins found in wheat, hordeins in barley, and secalins in rye, which are collectively named gluten. Avenins toxicity in celiac people depends on the oat cultivar consumed because of prolamin genes, protein amino acid sequences, and the immunoreactivities of toxic prolamins which
Rye bread upon this mixing of grains. Use of high-gluten wheat flour also makes possible multigrain breads, such as the "rye and Indian" bread of the American colonies, which combined rye and wheat with cornmeal in one loaf. Rye bread contains phenolic acids and ferulic acid dehydrodimers. Pure rye bread contains only rye flour, without any wheat. German-style pumpernickel, a dark, dense, and close-textured loaf, is made from crushed or ground whole rye grains, usually without wheat flour, baked for long periods at low temperature in a covered tin. Rye and wheat flours are often used to produce a rye bread with