Bulking Up Fiber's Healthful Reputation
by Ruth Papazian

More benefits of 'roughage' are discovered because it causes gas, bloating, and other uncomfortable side effects, fiber may be the Rodney Daingerfield 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.

The most recent claim, approved in January 1997, allows food companies to state on product labels that foods with soluble fiber from whole oats may reduce heart disease risk when eaten as part of a diet low in saturated fat and cholesterol. Foods covered include rolled oats, oat bran, and whole-oat flour.

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 Benefits: what can fiber do for you?

Recent findings on the health effects of fiber show it may play a role in:

Cancer - Epidemiological 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. The exact mechanism for reducing the risk is not known, but scientists theorize that insoluble fiber adds bulk to stool, which in turn dilutes carcinogens and speeds their transit through the lower intestines and out of the body.

Digestive disorders - Because insoluble fiber aids digestion and adds bulk to stool, it hastens passage of fecal material through the gut, thus helping to prevent or alleviate constipation.

Fiber also may help reduce the risk of diverticulosis, a condition in which small pouches form in the colon wall (usually from the pressure of straining during bowel movements). People who already have diverticulosis often find that increased fiber consumption can alleviate symptoms, which include constipation and/or diarrhea, abdominal pain, flatulence, and mucus or blood in the stool.

Diabetes - As with cholesterol, soluble fiber traps carbohydrates to slow their digestion and absorption. In theory, this may help prevent wide swings in blood sugar level throughout the day. Additionally, a new study from the Harvard School of Public Health, published in the Feb. 12 issue of the Journal of the

American Medical Association, suggests that a high-sugar, low-fiber diet more than doubles women's risk of Type II (non-insulin-dependent) diabetes. In the study, cereal fiber was associated with a 28 percent decreased risk, with fiber from fruits and vegetables having no effect. In comparison, cola beverages, white bread, white rice, and French fries increased the risk.

Obesity - Because insoluble fiber is indigestible and passes through the body virtually intact, it provides few calories. And since the digestive tract can handle only so much bulk at a time, fiber-rich foods are more filling than other foods--so people tend to eat less. Insoluble fiber also may hamper the absorption of calorie-dense dietary fat. So, reaching for an apple instead of a bag of chips is a smart choice for someone trying to lose weight.