The fiber-rich outer layer of the oat grain, separated from the rest of the grain during milling. Oats themselves have been eaten for thousands of years, but oat bran became widely popular as a distinct product in the 1980s, after research linked its soluble fiber, beta-glucan, to lower cholesterol. It is used in hot cereal, granola, and baked goods such as breads and muffins, where it adds a nutty flavor and fibrous texture, and can also serve as a coating for meat and vegetables or a thickener for soups and stews.