Facts About Fiber¹

Jennifer Hillan, R. Elaine Turner, and Wendy J. Dahl²

What is fiber? Why do we need it?

Fiber is found in fruits, vegetables, grains, and beans. Unlike sugar and starches, fiber is a carbohydrate that we cannot digest. Adequate fiber intake can help us maintain good health in a number of ways (1).

Some types of fiber help slow down the body's absorption of glucose (sugar). This can help in control of blood glucose.
Some types of fiber help to reduce blood cholesterol. This can help reduce the risk of heart disease.
Other types of fiber help keep our bowel function regular.
High-fiber foods make us feel full longer after eating. This may help with weight control.

Different foods have different types of fiber. It's important to eat a wide variety of plant foods to get the most health benefit from fiber.

What happens if we don't get enough fiber?

Fiber helps us form larger, softer stools that pass with regularity. Without enough fiber, we may suffer from constipation and hemorrhoids.

How much fiber do we need?

Recommendations for fiber intake are based on studies of the amounts needed to reduce heart disease risk. This level of fiber intake will also help prevent constipation. Table 1 lists the recommended Adequate Intakes (AI) for fiber (1).

Table 1.

Fiber recommendations [Source: Institute of Medicine, Food and Nutrition Board. (2005). Dietary reference intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein, and amino acids (macronutrients). Washington, DC: National Academy Press.]

Life Stage	AI Amount (grams of fiber per day)
Men, ages 19–50	38
Men, ages 51+	30
Women, ages 19–50	25
Women, ages 51+	21
Pregnancy	28
Breastfeeding	29

How can we get enough fiber?

Fruits, vegetables, beans, and whole grains provide fiber. Fruits and vegetables with edible skins and seeds are good choices for fiber. Most juices have almost no fiber, so choose whole fruits and vegetables more often. Read food labels to find good fiber sources!

Make sure that at least half of your daily grain servings are whole grain. Look for products that have a whole grain such as whole wheat, brown rice or whole rye first on the ingredient list, as these will usually contain the most fiber.

What about fiber supplements?

It's best to get fiber from food rather than from supplements. Not only are foods more enjoyable to eat, but they also are packed with nutrients needed for good health, such as vitamins and minerals. Fiber supplements usually don't have these added benefits. If you think you need a supplement, first talk to your healthcare provider.

For more information on fiber supplements, see EDIS publication Guide to Fiber Supplements (FSHN11-01) at http://edis.ifas.ufl.edu/fs162.

Table 2.

Fiber contents of selected foods

Food	Fiber (grams)
Lentils, cooked, 1 cup	16
Peanuts, boiled, 1 cup shelled	16
Black beans, cooked, 1 cup	15
Figs, dried, ½ cup	7
Wheat-bran flakes cereal, 1 cup	7
Prunes, dried or canned, ½ cup	6
Orange, raw, 1 large	4
Popcorn, air-popped, 3 cups	4
Potato, baked, with skin, 1 medium	4
Barley, pearled, cooked, ½ cup	3
Oatmeal, cooked, ½ cup	2
Whole wheat bread, 1 slice	2

How much fiber is too much?

There is no upper limit for fiber from whole grains, fruits, vegetables, and beans (1). The main problems caused by very high intakes of fiber are gas, bloating and distention.

Where can I get more information?

The Family and Consumer Sciences (FCS) agent at your county Extension office may have more written information and classes for you to attend. Also, a registered dietitian (RD) can provide reliable information to you.

A related EDIS publication is Shopping for Health: Whole Grains (FSHN10-13), available at http://edis.ifas.ufl.edu/fs161.

References

(1) Institute of Medicine, Food and Nutrition Board. (2005). Dietary reference intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein, and amino acids (macronutrients). Washington, DC: National Academy Press.

Footnotes

This document is FCS8793, one of a series of the Department of Family, Youth and Community Sciences, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date August 2006. Revised January 2011. Visit the EDIS website at http://edis.ifas.ufl.edu/.

Jennifer Hillan, MSH, RD, LD/N, former ENAFS nutrition educator/trainer, Department of Family, Youth and Community Sciences; R. Elaine Turner, PhD, RD, professor, Food Science and Human Nutrition Department; Wendy J. Dahl, PhD, assistant professor, Food Science and Human Nutrition Department; University of Florida; Gainesville, FL 32611.

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other extension publications, contact your county Cooperative Extension service.

U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, Dean.

Facts About Fiber1