Oat bran's dietary fiber is high in beta-glucan, which helps to lower cholesterol by binding bile acids and removing them from the body via the feces. The many studies demonstrate a very favorable effect on cholesterol levels: In individuals with high cholesterol levels (above 220 milligrams per deciliter) the consumption of the equivalent of 3 grams of soluble oat fiber per day typically lowers total cholesterol by 8 to 23 percent. This is highly significant, as with each 1 percent drop in serum cholesterol level, there is a 2 percent decrease in the risk of developing heart disease.

Studies also show that oat bran has beneficial effects on blood sugar as well. Adults with type 2 diabetes who were given foods high in oat fiber or given oatmeal- or oat bran-rich foods experienceed a much lower rise in blood sugar than those who were given white rice or bread.