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Fiber: How Much Is Enough?

CancerWise - March 2009

By Bayan Raji

When it comes to fiber, it seems the experts always say we don’t get enough. But the information out there can be confusing. How much fiber do we really need — and why?

Fiber is the part of grains, vegetables and fruits that our body does not digest. We generally hear about the importance of fiber when it comes to maintaining regular, healthy bowel movements. This may be of particular interest to cancer patients, since constipation is a common side effect of many types of cancer treatment, as well as some types of cancer.

In addition, fiber has been proven to help reduce the risk of heart disease and type 2 diabetes. The more fiber a person takes in daily, the less time harmful toxins spend inside the body, making them less likely to be absorbed by the bloodstream.

There are two types of fiber

Soluble fiber dissolves in water and:

  • Helps lower cholesterol
  • Helps regulate blood sugar
  • Is found in oats, dried beans and peas, nuts, fruits and psyllium husks (a dietary supplement in laxatives and over-the-counter products including Metamucil)

Insoluble fiber does not dissolve in water and:

  • Helps prevent constipation
  • Balances acidity in the intestines
  • Promotes regular bowel movements
  • Is found in green vegetables, whole wheat products, seeds and nuts

Both types are required for normal bowel function.

What’s the bottom line?

Follow these daily guidelines on how much you should consume:

  • Women: 25 to 30 grams
  • Men: 30 to 35 grams

No serious harmful effects of too much fiber have been found. However, taking a fiber supplement may decrease the effectiveness of some medications. Check with your health care practitioner before adding a fiber supplement to your diet. Supplements come in pill form or as a powder that can be added to food or drink.

Fruit is one of best methods for adding fiber, and men and women should have about two cups of fruit a day. Fruit and vegetable juices with 100% juice, as well as pulp, may contain fiber.

© 2015 The University of Texas MD Anderson Cancer Center