Oatmeal and oat bran are significant sources of dietary fiber. This fiber contains a mixture of about half soluble and half insoluble fibers. One component of the soluble fibre found in oats is beta-glucans, a soluble fiber which has proven effective in lowering blood cholesterol. Here's how it works. Soluble fiber breaks down as it passes through the digestive tract, forming a gel that traps some substances related to cholesterol, such as cholesterol-rich bile acids. This entrapment reduces the absorption of cholesterol into the bloodstream. The bad cholesterol, LDL, is trapped without lowering good cholesterol (HDL). Oats and grains are also one of the best sources of compounds called tocotrienols. These are antioxidants which together with tocopherols form vitamin E. The tocotrienols inhibit cholesterol synthesis and have been found to lower blood cholesterol. The accumulation of cholesterol is implicated in many types of cardiovascular disease. Oats, like all cholesterol-lowering agents, are most effective when consumed as part of a low-fat, high-fiber diet taken together with plenty of exercise. The beneficial health effects of oats are best if ½-1 cup (1½-3 ounces) of oats are eaten every day. One study found that the 1/10th ounce (3 grams) of soluble fiber from this amount of oatmeal decreased total cholesterol by approximately 2%, which correlates to a 4% decrease in coronary artery disease. Another study showed 1½ ounces (43 grams) of oatmeal lresulted in a loss of 3% in total cholesterol and a 14% reduction in bad cholesterol after two months. Another study found that a 6-8 week diet of 1½-3 ounces (43-85 grams) of oat bran daily lowered total cholesterol by 20% and bad cholesterol (LDL) by as much as 25%. Another study found 3.5 ounces (100 grams) of oat bran (one-third of a cup of oat bran eaten twice a day) lowered cholesterol up to 15%. New research has also discovered that the antioxidants found in oats reduce cholesterol by reducing the ability of blood cells to stick to the inside of artery walls. So in other words, eat a cup of oats a day and you'll be okay.