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 allergy high molecular weight glutenin subunit, and similar proteins in other "Triticeae" genera, enter the blood stream during exercise where they cause acute asthmatic or allergic reaction. One recent study of ω-gliadins demonstrated these gliadins are more similar to the bulk of oat avenins than α/β or γ gliadins but, so far, oat avenins have not been linked to WDEIA. Wheat may specifically induce WDEIA and certain chronic urticaria because the anti-gliadin IgE detects ω-gliadins expressed by most of the Gli-B1 alleles, but prolamins extracted from rye or wheat/rye translocates invoke almost no responses. The Gli-B1 gene in wheat, "Triticum aestivum",