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.
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