Fiber
Fiber
Other name(s):
b-glucan, cellulose, chitosan, gellan, guar gum, gum, hemicellulose, konjac mannan, lignin, mucilage pectin
General description
Fiber is present to some degree in almost all plant species. It’s also made by marine life, insects, yeasts, fungi, bacteria, and a host of other organisms. Fiber is often referred to as soluble or insoluble. This depends on whether it dissolves in water. Food sources include bran, whole grains, vegetables, fruits, and seaweed.
Studies suggest that fiber may help prevent colon cancer. It may also help treat diabetes and control high blood pressure.
Medically valid uses
Fiber has been shown in many studies to help prevent colon cancer. Many studies have shown that people and cultures whose diet is made up largely of fruits and vegetables have a lower rate of colon cancer. This is compared to those whose diet contains large amounts of meat and animal fats.
Fiber is also used to do the following:
Improve the taste and texture of food
Improve retention of water in foods
Prevent constipation
Provide body in liquid medicines
Fiber is also used as a no calorie or low-calorie meat expander in foods, such as hamburger. It’s also used as a low-calorie fat substitute. Fiber can also be used as a surgical dressing for wounds.
Unsubstantiated claims
Please note that this section reports on claims that have not yet been substantiated through scientific studies.
Fiber may help treat diverticulosis and diabetes. It may also help treat high cholesterol and high blood pressure.
Dosing format
The Adequate Intake (AI) for total fiber in foods is shown below:
Group |
Grams (g) of fiber per day |
Children ages 1–3 years |
19 g |
Children ages 4–8 years |
25 g |
Males 9–13 years |
31 g |
Females 9–13 years |
26 g |
Males 14–18 years |
38 g |
Females 14–18 years |
26 g |
Males 19–50 years |
38 g |
Females 19–50 years |
25 g |
Males 50 years and older |
30 g |
Females 50 years and older |
21 g |
Pregnant women |
28 g |
Lactating women |
29 g |
Many Americans don’t get enough fiber in their diet. When adding more fiber to your diet, increase it slowly over time. Make sure to drink plenty of water. This can reduce the risk of gastrointestinal issues.
Side effects, toxicity, and interactions
Some fibers can cause diarrhea. Others can cause constipation.
There are no known food or medicine interactions linked with fiber.
Updated:  
March 21, 2017
Sources:  
Position of the American Dietetic Association: Health Implications of Dietary Fiber. Journal of the American Dietetic Association. 2008, vol. 108, issue 10, pp. 1716–1731.
Reviewed By:  
Poulson, Brittany, RD,Wilkins, Joanna, R.D., C.D.