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|Bulking Up Fiber's|
|by Ruth Papazian|
A Reprint from FDA Consumer Magazine
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.
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.
FDA concluded that the beta-glucan soluble fiber of whole oats is the primary component responsible for lowering total and LDL (low-density lipoprotein), or "bad," blood cholesterol in diets including these foods at appropriate levels. 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.
The other three claims, allowed since 1993, are:
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? 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:
The evidence that a high-fiber diet can protect against breast cancer is equivocal. Researchers analyzing data from the Nurses' Health Study, which tracked 89,494 women for eight years, concluded in 1992 that fiber intake has no influence on breast cancer risk in middle-aged women. Previously, a review and analysis of 12 studies found a link between high fiber intake and reduced risk.
In the early stages, some breast tumors are stimulated by excess amounts of estrogen circulating in the bloodstream. Some scientists believe that fiber may hamper the growth of such tumors by binding with estrogen in the intestine. This prevents the excess estrogen from being reabsorbed into the bloodstream.
|High-fiber diets may help blunt the effects of|
smoking and other risk factors for heart disease.
As it passes through the gastrointestinal tract, soluble fiber binds to dietary cholesterol, helping the body to eliminate it. This reduces blood cholesterol levels, which, in turn, reduces cholesterol deposits on arterial walls that eventually choke off the vessel. There also is some evidence that soluble fiber can slow the liver's manufacture of cholesterol, as well as alter low-density lipoprotein (LDL) particles to make them larger and less dense. Researchers believe that small, dense LDL particles pose a bigger health threat.
Recent findings from two long-term large-scale studies of men suggest that high fiber intake can significantly lower the risk of heart attack. Men who ate the most fiber-rich foods (35 grams a day, on average) suffered one-third fewer heart attacks than those who had the lowest fiber intake (15 grams a day), according to a Finnish study of 21,903 male smokers aged 50 to 69, published in the December 1996 issue of Circulation. Earlier in the year, findings from an ongoing U.S. study of 43,757 male health professionals (some of whom were sedentary, overweight or smokers) suggest that those who ate more than 25 grams of fiber per day had a 36 percent lower risk of developing heart disease than those who consumed less than 15 grams daily. In the Finnish study, each 10 grams of fiber added to the diet decreased the risk of dying from heart disease by 17 percent; in the U.S. study, risk was decreased by 29 percent.
These results indicate that high-fiber diets may help blunt the effects of smoking and other risk factors for heart disease.
A word of caution: When increasing the fiber content of your diet, it's best to take it slow. Add just a few grams at a time to allow the intestinal tract to adjust; otherwise, abdominal cramps, gas, bloating, and diarrhea or constipation may result. Other ways to help minimize these effects:
But be leery of using fiber supplements for weight loss. In August 1991, FDA banned methylcellulose, along with 110 other ingredients, in over-the-counter diet aids because there was no evidence these ingredients were safe and effective. The agency also recalled one product that contained guar gum after receiving reports of gastric or esophageal obstructions. The manufacturer had claimed the product promoted a feeling of fullness when it expanded in the stomach.
|Reaching for an apple|
instead of a bag of chips
is a smart choice for
someone trying to lose weight.
An Apple a Day and More
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:
Ruth Papazian is a writer in Bronx, N.Y., specializing in health and safety issues.
Printed July 1997. This article originally appeared in the July-August 1997 FDA Consumer.
PUBLICATION NO. (FDA) 97-2313
|Department of Health And
Human Services . Public Health Service . Food and Drug Administration|
FDA on the Internet: http://www.fda.gov/
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