This conclusion is based on a scientific review showing a link between the soluble fiber in whole-oat foods and a reduction in coronary heart disease risk. Diets low in saturated fat and cholesterol and high in fiber are associated with a reduced risk of certain cancers, diabetes, digestive disorders, and heart disease. Diets low in saturated fat and cholesterol and rich in fruits, vegetables, and grain products that contain fiber, particularly soluble fiber, may reduce the risk of coronary heart disease. Found only in plant foods, such as whole grains, fruits, vegetables, beans, nuts, and seeds, fiber is composed of complex carbohydrates. Some fibers are soluble in water and others are insoluble.
Most plant foods contain some of each kind.
Some foods containing high levels of soluble fiber are dried beans, oats, barley, and some fruits, notably apples and citrus, and vegetables, such as potatoes. Foods high in insoluble fiber are wheat bran, whole grains, cereals, seeds, and the skins of many fruits and vegetables. However, since high-fiber foods may also contain antioxidant vitamins, phytochemicals, and other substances that may offer protection against these diseases, researchers can't say for certain that fiber alone is responsible for the reduced health risks they observe, notes Joyce Saltsman, a nutritionist with FDA's Office of Food Labeling. Epidemiologic studies have consistently noted an association between low total fat and high fiber intakes and reduced incidence of colon cancer. A 1992 study by researchers at Harvard Medical School found that men who consumed 12 grams of fiber a day were twice as likely to develop precancerous colon changes as men whose daily fiber intake was about 30 grams.