Fiber Helps Keep the Doctor Away

Fiber Helps Keep the Doctor Away

Jordan Lite Sep 14th 2010 12:13PM

An apple a day -- plus a few more fruits, vegetables and whole grains -- might really help keep the doctor away. All are packed with fiber, an ingredient science is increasingly showing may stave off heart disease, diabetes, cancer and weight gain.

Fiber, a.k.a. roughage, is a form of carbohydrate the body can't absorb. It's found in abundance in produce, beans, and grains such as brown rice and whole wheat.

"Most people come up short on their daily intake of fiber," says Sari Greaves, registered dietitian and spokeswoman for the
American Dietetic Association. "Most Americans only get about 15 grams, which is about half the amount your body needs."

Men 50 and younger should eat at least 38 grams of fiber a day, and women the same age should consume at least 25 grams, according to the
Institute of Medicine. Men 51 and up should get at least 30 grams of fiber daily, and women in that age bracket should eat 21. (The recommendations are based on how many calories we need, which tends to decline with age.)

Traditionally fiber has been touted for its ability to keep digestion regular. But it's healthy for other reasons, too.

Heart Disease

Numerous studies have shown that the greater a person's fiber consumption, the lower his risk of heart disease and heart-related death. A 2008 study in the
American Journal of Clinical Nutrition found that risk of coronary disease-related death dropped by 17 percent for every 10-gram increase in fiber consumption, and the risk of death from any cause fell by 9 percent.

Fiber may prevent heart disease for several reasons. It lowers LDL, or "bad" cholesterol, and reduces blood pressure and
insulin resistance (the body's ability to regulate sugar), all of which are risk factors for heart disease, according to a 2004 study in the Archives of Internal Medicine.

High fiber intake also is linked to lower levels of C-reactive
protein, says Katherine Tallmadge, registered dietitian and another ADA spokeswoman. C-reactive protein is a marker of inflammation that predicts recurrent strokes and possibly heart attacks in people who haven't had one before, according to the American Heart Association.

Tallmadge adds that fiber usually isn't working alone but is effective because it's bundled with other nutrients that promote health. In the case of heart disease, she says, high-fiber foods such as leafy greens, legumes and fortified cereals also contain folate, low levels of which are associated with coronary disease. "The fiber is only one of many of the reasons these foods prevent these diseases," Tallmadge says. "The fiber is really a marker of eating a lot of fruits, vegetables, whole grains, legumes -- basically a very healthy, diverse and plant-based


The jury is still out on whether fiber has an effect on
cancer development. A 2005 analysis of studies published in the Journal of the American Medical Association found that it made no difference in the development of colorectal cancer, but other research has suggested that fiber-rich diets reduce the risk of those tumors. Any beneficial effects may come not from the fiber but from vitamins and minerals in high-fiber foods, according to the National Cancer Institute.

"Typically, people eating high-fiber diets are also not eating foods high in
saturated fats, like fatty meats, butter and whole-milk dairy products, and saturated fat is associated with an increased risk of colon cancer," Greaves says.

The evidence for fiber as a cancer weapon is somewhat stronger for breast tumors. A British study that followed more than 35,000 women for up to nine years found that
breast cancer risk was lower among premenopausal -- but not postmenopausal -- women who ate fiber-rich diets. Fiber from cereals was linked to the least risk, and fiber-containing fruits had a "borderline" impact, the scientists wrote in 2007 in the International Journal of Epidemiology.

A study published last year in the
American Journal of Clinical Nutrition found a benefit for older women, too: Among 185,000 postmenopausal women, those who ate the most fiber had a 13 percent lower breast cancer risk than those who consumed the least.

Fiber may have an indirect effect on cancer by speeding the passage of food through the digestive tract and minimizing the amount of time the body is exposed to potentially harmful molecules, Greaves says.

Irritable Bowel Syndrome

People with
irritable bowel syndrome battle diarrhea, constipation, and the cramping and bloating that come with. Though it may seem counterintuitive, fiber can help manage IBS.

A study published this year in the
British Medical Journal that compared the fiber supplement psyllium with bran and a placebo found that IBS symptoms decreased most among patients taking psyllium. While they improved somewhat in those eating bran, many people in that arm of the trial dropped out because their symptoms got worse. For that reason, the Mayo Clinic recommends experimenting with types of fiber and increasing your consumption gradually.

Look for insoluble fiber found in bran and the skin of fruits and vegetables, Greaves suggests. Insoluble forms add bulk to stool that helps maintain bowel regularity. "I like to call them 'nature's broom' because they move through your digestive tract without being broken down, and in this way they can help promote regularity and prevent constipation," she says. Psyllium can be helpful, too; it's a soluble type of fiber that holds on to water, which helps slow digestion.


Fiber is a boon to people looking to prevent
diabetes and who already have the disease. Research has consistently shown that a diet that includes high-fiber cereals (those that contain whole grains) is associated with a lower risk of diabetes, according to a 2008 review in the Journal of Nutrition.

Fiber is good for people with diabetes because it doesn't raise blood sugar levels, according to the
Joslin Diabetes Center. And patients who eat high-fiber diets have lower fasting insulin levels, a marker of overall blood sugar, Tallmadge adds. Aim for 25 to 50 grams a day if you have the disease, doctors recommended in a 2004 study in the Journal of the American College of Nutrition.

"People with insulin resistance and diabetes would benefit from getting more soluble fibers because they prevent blood sugar swings that often happen in those conditions," Greaves says.

Weight Management

Fiber is a tool to
maintain and lose weight. Among 74,000 women followed for 12 years, those who ate the most fiber had a 49 percent lower risk of major weight gain than women who consumed the least, according to a 2003 study published in the American Journal of Clinical Nutrition.

Fiber works by making you feel full, so you eat less. And the highest-fiber foods also tend to be the lowest in calories, Greaves says, so long as that fiber occurs naturally. Manufactured products with fiber added to them tend to be higher in calories and less healthy overall, Tallmadge says.

"If you're watching your waistline, you may not want to go to the high-sugar granola to get your fiber," Greaves says. "You may want to go for a whole grain, unsweetened cereal instead."