Because it causes gas, bloating, and other uncomfortable side effects, fiber may be the Rodney Dangerfield of food constituents. But with more and more research showing that a high-fiber diet may help prevent a cancer, heart disease, and other serious ailments, roughage has started to get some respect.
The problem is that most Americans don't get enough fiber to realize its potential benefits. The typical American eats only about 11 grams of fiber a day, according to the American Dietetic Association. Health experts recommend a minimum of 20 to 30 grams of fiber a day for most people.
The Food and Drug Administration has recognized fiber's importance by requiring it to be listed on the Nutrition Facts panel of food labels along with other key nutrients and calories. And, based on scientific evidence, the agency has approved four claims related to fiber intake and lowered risk of heart disease and cancer.
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. The other three claims, allowed since 1993, are:
- Diets low in fat and rich in fiber-containing grain products, fruits, and vegetables may reduce the risk of some types of cancer.
- 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.
- Diets low in fat and rich in fruits and vegetables, which are low-fat foods and may contain fiber or vitamin A (as beta-carotene) and vitamin C, may reduce the risk of some cancers.
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. In a 1996 survey, however, when 1,009 Americans were asked which of five foods--lettuce, asparagus, navy beans, brown rice, and oatmeal--provided the best source of cholesterol-fighting soluble fiber, many missed the mark. Brown rice was incorrectly chosen by 64 percent, lettuce by 46 percent, and asparagus by 48 percent. In fact, only navy beans (chosen by 60 percent) and oatmeal (chosen by 75 percent) are rich sources of soluble fiber.
