Oat vary among oat varieties. Also, oats products are frequently cross-contaminated with other gluten-containing cereals during grain harvesting, transport, storage or processing. Pure oats contain less than 20 parts per million of gluten from wheat, barley, rye, or any of their hybrids. Use of pure oats in a gluten-free diet offers improved nutritional value from the rich content of oat protein, vitamins, minerals, fiber, and lipids, but remains controversial because a small proportion of people with celiac disease react to pure oats. Some cultivars of pure oat could be a safe part of a gluten-free diet, requiring knowledge of the oat
Wheat gluten (food) markets, health food stores and cooperatives. The block form of seitan is often flavored with shiitake or portobello mushrooms, fresh coriander or onion, or barbecue sauce, or packed in a vegetable-based broth. In strip form, it can be packed to be eaten right out of the package as a high-protein snack. Shaped seitan products, in the form of "ribs" and patties, are frequently flavored with barbecue, teriyaki, or other savory sauces. Wheat gluten is also used in many vegetarian products in various countries, for example by The African Hebrew Israelites of Jerusalem, a vegan African American religious sect that operates