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 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.
Fiber’s Health BenefitsWhat can fiber do for you? Numerous epidemiologic (population-based) studies have found that 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. 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. “Moreover, no one knows whether one specific type of fiber is more beneficial than another since fiber-rich foods tend to contain various types,” she adds.
Recent findings on the health effects of fiber show it may play a role in:
These results indicate that high-fiber diets may help blunt the effects of smoking and other risk factors for heart disease.
Recent research suggests that as much as 35 grams of fiber a day is needed to help reduce the risk of chronic disease, including heart disease. A fiber supplement can help make up the shortfall, but should not be a substitute for fiber-rich foods. “Foods that are high in fiber also contain nutrients that may help reduce the risk of chronic disease,” Saltsman notes. In addition, eating a variety of such foods provides several types of fiber, whereas some fiber supplements contain only a single type of fiber, such as methylcellulose or psyllium.
To fit more fiber into your day:
- Read food labels. The labels of almost all foods will tell you the amount of dietary fiber in each serving, as well as the Percent Daily Value (DV) based on a 2,000-calorie diet. For instance, if a half cup serving of a food provides 10 grams of dietary fiber, one serving provides 40 percent of the recommended DV. The food label can state that a product is “a good source” of fiber if it contributes 10 percent of the DV–2.5 grams of fiber per serving. The package can claim “high in,” “rich in” or “excellent source of” fiber if the product provides 20 percent of the DV–5 grams per serving.
- Use the U.S. Department of Agriculture’s food pyramid as a guide. If you eat 2 to 4 servings of fruit, 3 to 5 servings of vegetables, and 6 to 11 servings of cereal and grain foods, as recommended by the pyramid, you should have no trouble getting 25 to 30 grams of fiber a day.
- Start the day with a whole-grain cereal that contains at least 5 grams of fiber per serving. Top with wheat germ, raisins, bananas, or berries, all of which are good sources of fiber.
- When appropriate, eat vegetables raw. Cooking vegetables may reduce fiber content by breaking down some fiber into its carbohydrate components. When you do cook vegetables, microwave or steam only until they are al dente–tender, but still firm to the bite.
- Avoid peeling fruits and vegetables; eating the skin and membranes ensures that you get every bit of fiber. But rinse with warm water to remove surface dirt and bacteria before eating. Also, keep in mind that whole fruits and vegetables contain more fiber than juice, which lacks the skin and membranes.
- Eat liberal amounts of foods that contain unprocessed grains in your diet: whole-wheat products such as bulgur, couscous or kasha and whole-grain breads, cereals and pasta.
- Add beans to soups, stews and salads; a couple of times a week, substitute legume-based dishes (such as lentil soup, bean burritos, or rice and beans) for those made with meat.
- Keep fresh and dried fruit on hand for snacks.
“So many foods contain fiber that it’s really not that hard to get your intake up where it should be,” Saltsman says.
