Fiber For Heart Health A high Fiber Diet Prevents
Heart Disease
Bulking Up Fiber's Healthful Reputation more Benefits
of 'Roughage' Are Discovered
by Ruth Papazian
Because it causes gas, bloating, and other uncomfortable side
effects,it 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 of it 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 a day for most
people.
Fiber For Heart Health The FDA's 4 Food Claims
One claim states that dietary soluble fiber,
when part of a diet low in saturated fat and cholesterol, may reduce
the risk of coronary heart disease. In 1997, FDA approved this claim
for certain foods containing whole oats and in 1998, for certain
foods containing psyllium seed husk.
The other three claims, allowed since 1993, are:
- Diets low in fat and rich in fiber-containing grain products,
fruits, and vegetables may reduce the risk of some types of cancer.
- Diets low in saturated fat and cholesterol and rich in fruits,
vegetables, and grain products that contain fiber, particularly
soluble fiber, may reduce the risk of coronary heart disease.
- Diets low in fat and rich in fruits and vegetables, which are
low-fat foods and may contain fiber or vitamin A (as beta-carotene)
and vitamin C, may reduce the risk of some cancers.
Fiber For Heart Health can be found in plants and beans
Found only in plant foods, such as whole grains,
fruits, vegetables, beans, nuts, and seeds, it is composed of complex
carbohydrates. Some 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 For Heart Health - The Health Benefits
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 it
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 is more beneficial
than another since fiber-rich foods tend to contain various types
she adds.
Besides for Fiber For Heart Health Recent Findings
on the Health Effects 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 it 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. It 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 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.
Fiber For Heart Health Recent Studies and Findings
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 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 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.
But be leery of using 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.
Fiber For Heart Health - 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 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 supplements
contain only a single type, such as methylcellulose or psyllium.
Fiber For Heart Health - To fit more into your day:
- Read food labels. The labels of almost all
foods will tell you the amount of dietary fiber in each serving,
as well as the Percent Daily Value (DV) based on a 2,000-calorie
diet. For instance, if a half cup serving of a food provides 10
grams of dietary fiber, one serving provides 40 percent of the
recommended DV. The food label can state that a product is a good
source of fiber if it contributes 10 percent of the DV--2.5 grams
per serving. The package can claim "high in," "rich in" or "excellent
source of" fiber if the product provides 20 percent of the DV--5
grams per serving.
- Use the U.S. Department of Agriculture's food pyramid
as a guide. If you eat 2 to 4 servings of fruit, 3 to
5 servings of vegetables, and 6 to 11 servings of cereal and grain
foods, as recommended by the pyramid, you should have no trouble
getting 25 to 30 grams a day.
- Start the day with a whole-grain cereal that
contains at least 5 grams per serving. Top with wheat germ, raisins,
bananas, or berries, all of which are good sources of fiber.
- When appropriate, eat vegetables raw. Cooking
vegetables may reduce fiber content by breaking down some fiber
into its carbohydrate components. When you do cook vegetables,
microwave or steam only until they are al dente--tender, but still
firm to the bite.
- Avoid peeling fruits and vegetables; eating
the skin and membranes ensures that you get every bit of fiber.
But rinse with warm water to remove surface dirt and bacteria
before eating. Also, keep in mind that whole fruits and vegetables
contain more fiber than juice, which lacks the skin and membranes.
- Eat liberal amounts of foods that contain unprocessed
grains in your diet: whole-wheat products such as bulgur,
couscous or kasha and whole-grain breads, cereals and pasta.
- Add beans to soups, stews and salads; a couple
of times a week, substitute legume-based dishes (such as lentil
soup, bean burritos, or rice and beans) for those made with meat.
- Keep fresh and dried fruit on hand for snacks.
"So many foods contain fiber that it's really not that hard to
get your intake up where it should be," Saltsman says.
Ruth Papazian is a writer in Bronx, N.Y., specializing
in health and safety issues.
Fiber For Heart Health Slow Going a Word of Caution
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:
- Drink at least 2 liters (8 cups) of fluid daily.
- Don't cook dried beans in the same water you soaked them in.
- Use enzyme products, such as Beano or Say Yes To Beans, that
help digest fiber.
This article was originaly published in the FDA Consumer
and may be republished without permission.
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