One claim states that dietary soluble fiber, when part of a diet low in saturated fat and cholesterol, may reduce the risk of coronary heart disease. In 1997, FDA approved this claim for certain foods containing whole oats and in 1998, for certain foods containing psyllium seed husk. 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. Brown rice was incorrectly chosen by 64 percent, lettuce by 46 percent, and asparagus by 48 percent. 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.