Why is dietary fiber so important?

Rebecca Katz, MS
Nutrition & Dietetics
Dietary fiber is important because it's a nutrient that helps rid the body of debris and toxins. In this video, culinary nutritionist Rebecca Katz, MS, explains why dietary fiber is key for good health, and shares some good food sources of fiber. 
Dr. Michael Roizen, MD
Internal Medicine
In any given day, lots of things enter our mouths-air, water, a piece of Bazooka gum. To prevent problems associated with your digestive system, fiber is one of the best things that can enter your intestinal pathway.

Fiber is the community-service director of the major food groups-it's not a sexy job, but it sure does do great things. It's largely indigestible as it passes through the digestive tract intact. Found solely in plant foods, fiber contains no calories but makes you feel full, which helps control overeating.

Most importantly, it helps keep digested food bulky and soft-so it's easy to pass through the colon. It makes it easier for the food to move through your intestines without much pressure being placed along your tubing. And that's important for avoiding such things as diverticulitis and hemorrhoids.

Both kinds of fiber-insoluble fiber and soluble fiber-are good for you.

Insoluble fiber doesn't easily dissolve in water and is not broken down by intestinal bacteria. (This type doesn't lower your cholesterol but still has an effect on your digestive system.) It's found in grapefruit, oranges, grapes, raisins, dried fruit, sweet potatoes, peas and zucchini-but especially in whole-wheat or whole-grain bread (it has to be whole grain, not five- or six-grain, to have enough fiber).

Soluble fiber dissolves in water; it regulates metabolism and digestion and stabilizes blood glucose levels. And it's mostly found in grains such as oats, barley, and rye, legumes such as beans, peas, and lentils, and some cereals.

Eating 25 grams of fiber a day can give you a RealAge effect of being as much as three years younger than that of a person who only eats 12 grams a day (the average for American adults). Plus, one study showed that a 10-gram increase in the daily intake of fiber decreases the risk of heart attack by 29 percent-and makes you 1.9 years younger.

YOU: The Owner's Manual, Updated and Expanded Edition: An Insider's Guide to the Body that Will Make You Healthier and Younger

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Most Americans eat well below the recommended daily amounts of fiber (25 grams for women; 38 grams for men), so be sure to fill up on high-fiber foods, such as whole grains, beans, fruits, and vegetables. These are nutritious and help prolong the feeling of fullness, which is critical if you're trying to lose weight. A high-fiber diet that is low in saturated fat and cholesterol may help protect against heart disease.
Tanya Zuckerbrot
Nutrition & Dietetics
Adding fiber-rich foods to your diet is one of the best things you can do to increase your chances for a long and healthy life.  If you saw a food label that said "May reduce the risk of heart disease, diabetes, cancer, could lower your cholesterol and control your appetite" you would think it was a scam. Yet that is exactly what fiber does!

Fiber helps lower cholesterol by binding with cholesterol in the gastrointestinal tract and ushering it out of the body before it has a chance to reach the bloodstream, where it would otherwise clog up arteries.

Fiber decreases the risk for diabetes. This is due to the fact that fiber helps control blood sugar levels throughout the day. Studies have shown that people who eat a high-fiber diet lowered their risk of diabetes by 30 percent.

Fiber decreases the risk for breast cancer. As reported in the Journal of Clinical Oncology, researchers found that a diet including 20-30 grams of fiber per day can lower blood estrogen levels. Estrogen stimulates the early growth and development of breast cancer. Therefore, the less estrogen you have in your body, the lower your cancer risk.

Fiber reduces blood pressure. Fiber reduces insulin resistance-a suspected step in developing high blood pressure -- and inhibits weight gain -- a known hypertension risk factor.

Fiber increases elimination and protects against colon cancer. Diets high in fiber (30 grams or more) have been shown to reduce the risk of colon cancer by 40 percent.

I admit it -- fiber isn't sexy. But when it comes to losing weight, nothing is more effective, fiber fills you up without filling you out. Combined with all the additional health benefits, you would be cheating yourself if you did not incorporate fiber into your daily diet. 
Starting your day with oats, bran or anything high in fiber could increase your lung capacity and help you breathe easier.

In a study, people who ate at least 27 grams of fiber per day had better lung capacity than people who got less than 10 grams. The high-fiber eaters were also 15% less likely to develop chronic obstructive pulmonary disease, an irreversible lung condition that makes it hard to breathe. Fiber may protect lungs by reducing tissue-damaging inflammation. The antioxidants in fiber probably help protect lung cells, too.

Fiber is also good for:
  • Your waistline. Fiber helps fill you up, so you munch less.
  • Your blood pressure. When your blood pressure creeps up, knock it back down with extra fiber.
  • Your bowels. Fiber helps keep you regular.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.