Q. How do “cholesterol-lowering” cereals like oatmeal reduce LDL cholesterol? How much do I need to eat to make a difference?
A. Fruits, vegetables, and whole grains are part of a heart healthy diet. Part of the benefit of eating these foods is that they crowd out the high fat and processed foods associated with heart disease and some cancers. These healthful foods are also rich in fiber.
Fiber is known to help control LDL (bad) cholesterol. Studies have shown that soluble fiber—found in oat bran, psyllium, and pectin, for example—can independently lower LDL cholesterol in people with a wide range of baseline cholesterol levels.
And how much oatmeal or cereal does a person need to consume to benefit? Harvard researchers examined 67 studies of soluble fiber and concluded that 3 grams daily lowers LDL cholesterol by 5 milligrams per deciliter (mg/dL). For someone with an average amount of LDL (120-150 mg/dL), this represents a 3% to 4% decrease, which can trim the risk of heart disease by a similar amount.
One gram of soluble fiber can be found in an apple, a half-cup of cooked carrots or broccoli, two slices of whole grain bread, or a serving of oatmeal. Therefore, the effect is a positive one for someone trying to eat a healthy diet, but the LDL decrease is probably not large enough to replace medication for someone aiming to decrease LDL by 50-60 mg/dL—like many people with diabetes and heart disease.
— William Kormos, M.D.
Editor in Chief, Harvard Men’s Health Watch