The oat (Avena sativa), sometimes called the common oat, is a species of cereal grain grown for its seed, which is known by the same name (usually in the plural, unlike other cereals and pseudocereals). While oats are suitable for human consumption as oatmeal and rolled oats, one of the most common uses is as livestock feed. Oats are a nutrient-rich food associated with lower blood cholesterol when consumed regularly. Avenins are oat gluten proteins, similar to gliadin in wheat. They can trigger celiac disease in a small proportion of people. Also, oat products are frequently contaminated by other gluten-containing grains, mainly wheat and barley. Origin The wild ancestor of Avena sativa and the closely related minor crop A. byzantina is A. sterilis. A. sterilis is a wild oat that is naturally hexaploid. Genetic evidence shows the ancestral forms of A. sterilis grew in the Fertile Crescent of the Near East. Oats are usually thought to have emerged as a secondary crop, i.e., derived from a weed of the primary cereal domesticates, then spreading westward into cooler, wetter areas favorable for oats, eventually leading to their domestication in regions of the Middle East and Europe. Cultivation Oats are best grown in temperate regions. They have a lower summer heat requirement and greater tolerance of rain than other cereals, such as wheat, rye or barley, so they are particularly important in areas with cool, wet summers, such as Northwest Europe and even Iceland. Oats are an annual plant, and can be planted either in autumn/fall (for late summer harvest) or in the spring (for early autumn/fall harvest). Production In 2017, global production of oats was , a 13% increase over 2016. Production was led by Russia with 21% of the total and Canada with 14% (table). Other substantial producers were Australia, Poland, China, and Finland, each with over . oat is the seventh most produced cereal in the world. Uses Oats have numerous uses in foods; most commonly, they are rolled or crushed into oatmeal, or ground into fine oat flour. Oatmeal is chiefly eaten as porridge, but may also be used in a variety of baked goods, such as oatcakes, oatmeal cookies and oat bread. Oats are also an ingredient in many cold cereals, in particular muesli and granola. Oats are also used for production of milk substitutes ("oat milk"). Historical attitudes towards oats have varied. Oat bread was first