Major sources of dietary gluten.
The four grains most directly associated with gluten are wheat, barley, rye and triticale, which is a cross between rye and wheat. Variations, which are often sold with “healthy” labeling, are spelt, kamut, bulgur wheat, semolina, einkorn, faro, graham flour, durum flour or in fact any kind of flour that is not specifically labeled “gluten-free.” Couscous in any form is a wheat product. The Asian product seitan is made from wheat gluten.
Since these grains are used for nearly all ready-to-eat breakfast cereals, breads, crackers, pastas, pizza dough, cookies, cakes, pastries and other baked goods, these products are forbidden unless specifically labeled “gluten-free.”
Oats are themselves gluten-free, but producers often use the same machinery for oats and wheat, leading to cross-contamination concerns. Health brands of oats are now available that guarantee that the oats have been processed in a wheat-free environment.