What are the benefits of dietary fiber?

Research shows the critical role dietary fiber plays in preventing chronic health problems. When you ingest sufficient amounts of fiber, it aids glucose management in a way that helps reduce the risk of diabetes. It also, in turn, helps reduce obesity. A different study discovered that a high-fiber diet reduces the damaging effects of allergy-induced airway disease, which leads to asthma.

A separate British study found that adding 7 grams (g) of fiber per day measurably increased heart health. If you don’t already eat a high-fiber diet, make sure you get supplemental fiber and ingest around 30 g per day.
Dr. Michael Roizen, MD
Internal Medicine

Dietary fiber such as prebiotic fiber can promote digestive health. 70% of your immunity is in your gut and as a result a healthy gut or digestive system can contribute to a healthy immune system. In addition to a balanced diet, larch arabinogalactan supplements, which contain prebiotic fiber promote digestive health and are clinically proven to naturally activate your immune system.

William B. Salt II., MD
Fiber is necessary to promote normal peristalsis, the wavelike muscular contractions that move food along the intestinal tract. As fiber passes along, it absorbs water, which softens and bulks up the stool. Higher stool bulk results in softer and larger stools for most people and eases the elimination of stool. With more bulk, pressure in the colon is actually reduced -- it does not have to contract as strongly to propel the stool along. This is important for people who have constipation, since most will benefit by increasing dietary fiber intake. This point cannot be stressed enough. In fact, some constipated people may require more fiber than the recommended 20 to 35 grams per day. Severe forms of constipation may not respond to fiber and require other forms of treatment.

Some people with chronic diarrhea benefit by increased fiber intake, as fiber absorbs water from the stool and increases consistency. The fiber supplement psyllium may be particularly beneficial.

Increased fiber intake can relieve symptoms of hemorrhoids and difficulty cleansing the anal area by improving stool consistency and frequency and by reducing the adherence of stool following defecation. Again, psyllium seems to be especially helpful here.

Finally, diverticulosis of the colon (occurs when small outpouchings, called diverticula, form in the colon wall) is correlated with low dietary fiber intake. A high fiber intake can actually reduce the pressure within the colon and is particularly helpful if constipation is also present. Contrary to popular belief, there is no evidence that small seeds and grains, nuts and popcorn cause complications from diverticulosis.
Irritable Bowel Syndrome & the MindBodySpirit Connection: 7 Steps for Living a Healthy Life with a Functional Bowel Disorder, Crohn's Disease, or Colitis (Mind-Body-Spirit Connection Series.)

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Irritable Bowel Syndrome & the MindBodySpirit Connection: 7 Steps for Living a Healthy Life with a Functional Bowel Disorder, Crohn's Disease, or Colitis (Mind-Body-Spirit Connection Series.)

Fast Facts on IBS: One in five people suffers from the frustrating symptoms of Irritable Bowel Syndrome (IBS). There is no simple answer--no pill, potion, or quick fix--that will cure IBS. But help...
Ms. Ashley Koff, RD
Nutrition & Dietetics
Dietary fiber is critical to a healthy diet and the proper functioning of our bodies. It helps us feel full; it aids digestion both by adding bulk to stool and by scraping the lining of the digestive tract (our built-in "cleaning system"); it aids heart health; and as a prebiotic (a material that helps good bacteria to grow and flourish), it promotes a hospitable environment for probiotics (the good bacteria that help our digestion and support our immune system).

You'll find fiber in the skins of fruits and vegetables (like arugula), legumes, sprouts, and grains (especially whole grains). It helps to moderate the body's absorption of sugars. For example, that's why I usually recommend eating whole fruit instead of drinking fruit juice; in the absence of fiber, the sugar in juice is absorbed very quickly.
Dr. David L. Katz, MD, MPH
Preventive Medicine
Dietary fibers can lower blood pressure, and cholesterol, and insulin; can stabilize blood sugar; can improve gastrointestinal health, and potentially lower cancer risk; and can help produce satiety that facilitates weight control. So they are only important for anyone at risk for conditions that cumulatively affect at least 80% of the entire population!
Grant Cooper, MD
Physical Medicine & Rehabilitation
Fruits and vegetables are excellent sources of fiber. Most of us do not eat enough fiber. Eating more fiber will reduce your risk of constipation, help cleanse toxins from your colon, reduce potential discomfort, and help your body absorb the important nutrients you are consuming.
The Arthritis Handbook: Improve Your Health and Manage the Pain of Osteoarthritis (A DiaMedica Guide to Optimum Wellness)

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The Arthritis Handbook: Improve Your Health and Manage the Pain of Osteoarthritis (A DiaMedica Guide to Optimum Wellness)

According to conventional wisdom, arthritis pain is an inevitable part of aging. Not so, says Dr. Grant Cooper in this practical, accessible guide. For those who do develop osteoarthritic conditions,...
Dr. Doris Day, MD
Fiber used to be considered a basically useless filler because it’s not a nutrient. Now, however, we know that fiber reduces the risk of many serious health conditions including heart disease, diabetes, obesity, colon cancer, and hemorrhoids. Fiber also makes for good digestion and elimination, which helps your skin look vibrant and healthy.

By some estimates, the average American eats only about one-third of the amount of fiber needed daily for peak health. Be sure you include whole grains, especially bran, in your diet every day and that you eat fruits whole so that you’ll get enough fiber.
Dr. Mehmet Oz, MD
Cardiology (Cardiovascular Disease)
The benefit of consuming fiber-rich foods like vegetables, legumes and whole grains is manifold. Fiber helps to alleviate constipation, lowers your risk of heart disease and diabetes, and it also aids in weight loss. The drawback here is gas. To stop gas, find the source of your problem. For one week, eliminate all sources of fiber but one. If you find you’re gas-free, introduce another fiber-rich food. Do this until you figure out which food is making you more flatulent. Psyllium and methylcellulose, fiber supplements, are recommended alternatives.
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There are two types of dietary fiber: soluble and insoluble. All fiber-containing foods contain a combination of both, and both are beneficial. Water-soluble fiber helps lower cholesterol by binding with it during digestion and flushing it from your system. Insoluble fiber absorbs water during the digestion process, and thus helps prevent constipation.

Japanese researchers have found an even stronger correlation between dietary fiber intake and rates of colon and colorectal cancers. Study participants with the highest fiber intake had a 27 percent reduced risk for colorectal cancer and a 42 percent reduced risk for colon cancer. Researchers speculate that these results are due to the tendency of insoluble fiber to promote regularity.
Michael T. Murray, ND
Naturopathic Medicine
The physiological effects of dietary fiber impact stool weight and transit time, digestion, lipid metabolism, short-chain fatty acids (SCFA), and intestinal bacterial flora.

The beneficial effects of dietary fiber are:
  • Decreased intestinal transit time
  • Delayed gastric emptying, resulting in reduced after-meal blood sugar level
  • Increased satiety
  • Increased pancreatic secretion
  • Increased stool weight
  • More advantageous intestinal micro flora
  • Increased production of short-chain fatty acids
  • Decreased serum lipids
  • More soluble bile
Encyclopedia of Healing Foods

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Encyclopedia of Healing Foods

From the bestselling authors of The Encyclopedia of Natural Medicine, the most comprehensive and practical guide available to the nutritional benefits and medicinal properties of virtually everything...

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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.