The Oat (Avena sativa) is a species of cereal grain, and the seeds of this plant. They are used for food for human consumption and as fodder for animals, especially poultry and horses. Oats are generally considered healthy, and the discovery of the healthy cholesterol-lowering properties has led to wider appreciation of oats as human food. Oat bran is the outer casing of the oat. Its consumption is believed to lower LDL ("bad") cholesterol, and possibly to reduce the risk of heart disease.