|
Why is Fiber Important in Your Diet?
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:
- Cancer: Epidemiologic 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.
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.
- 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.
- Heart Disease: Clinical studies
show that a heart-healthy diet (low in saturated fat and cholesterol,
and high in fruits, vegetables and grain products that contain soluble
fiber) can lower blood cholesterol. In these studies, cholesterol levels
dropped between 0.5 percent and 2 percent for every gram of soluble
fiber eaten per day.
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.
- 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.
Click here to discover Summertime One
Day Diet.
The Solution is Simple
One Day Diet
Powerful Weight Loss in Sweet Simplicity
Click Here to Get
One Day Diet Now
Click Here to Get
One Day Diet Free Samples
|
