What is Fiber?
Dietary fiber is a type of carbohydrate that is not digestible by the body. Although it’s not digested, it has a number of jobs in our body. Fiber can lower cholesterol, stabilize blood sugar, and bulk up stool, which keeps us “regular.” New research also shows that fiber can be a prebiotic; the food from which good gut bacteria feeds.
What are the Different Types of Fiber?
There are two types of fiber – soluble and insoluble.
Soluble fiber dissolves in water and becomes gelatinous. The expansion of soluble fiber in water is associated with quicker and longer satiety when eating, a slower digestion of carbohydrates to maintain blood sugar, and the prevention of constipation. Sources of soluble fiber include apples, blueberries, oats, and beans.
Insoluble fiber does not dissolve in water, thus remaining intact, which helps to push food through your digestive system. Sources of insoluble fiber include whole grain breads, the skins of fruits and vegetables, celery, and brown rice.
How Much Fiber Should People Get?
It is recommended by the Dietary Guidelines for Americans 2015-2020 that adults consume between 25 to 38 grams of fiber per day, depending on age and gender. The recommendation for children is 14 to 30 grams per day, depending on age and gender.
What Foods Contain Fiber?
Dietary fiber is found in plant-based foods such as whole grains, fruits, vegetables, beans and legumes. The amount of fiber in each food differs, depending on the source. For example, beans and legumes contain approximately 8-9 grams of fiber per ½-cup portion, while a medium apple, with skin, contains 4-5 grams of fiber, and frozen mixed vegetables contain 4 grams of fiber per ½-cup serving. Whole wheat bread contains, on average, 3 grams of fiber per slice.
The Bottom Line:
In order to consume your recommended amount of fiber, choose a variety of whole foods such as whole grains, fruit, vegetables, beans, and legumes on a daily basis. To determine how much fiber is recommended for you, check out the Dietary Guidelines for Americans, 2015-2020, Appendix 7. If you are interested in seeing how much fiber is in your favorite foods, read the Nutrition Facts food label. You will find fiber listed under the Total Carbohydrate section. Aim for 8-10 grams of dietary fiber per meal, and be mindful of the fiber content in your snack choices as well. Dietary fiber is essential because it supports weight management, promotes disease management, and aids in the prevention of heart disease, diabetes, and bowel diseases.
By Beth Rosen, MS, RD, CDN
Stephanie Ronco has been editing for Food and Health Communications since 2011. She graduated from Colorado College magna cum laude with distinction in Comparative Literature. She was elected a member of Phi Beta Kappa in 2008.