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.
