Dietary Fiber

Also known as roughage or bulk, dietary fiber is the part of plant foods that our bodies find indigestible and nonabsorbable. While at face value this may sound like a negative, indigestible fibers actually play a key role in digestive health.

There are two types of dietary fiber; soluble and insoluble. Soluble fiber dissolves in water and can be helpful for lowering cholesterol and maintaining healthy blood sugar levels. It is also known for aiding with healthy weight loss by providing a feeling of fullness and alleviating hunger for longer.  Insoluble fiber on the other hand does not dissolve in water, instead absorbing it, creating bulk and helping move food along the digestive tract. This aids in preventing constipation and irregular bowel movements.3

Dietary fiber promotes a healthy gastrointestinal microbiome, enabling optimal absorption of nutrition and reducing inflammation and bloating.  A good balance of insoluble and soluble fibers provides an environment where gut bacteria is able to thrive and waste materials are able to pass in a healthy, efficient manner. This averts bacteria from feeding on intestinal mucus linings and reduces the fermentation of non-digested foods.1,2

Because of the nourishment dietary fibers provide the gut microbiome through fermentation, many are considered prebiotic; while not all dietary fibers are considered prebiotics, most prebiotics are classified as dietary fibers.1

  1. Holscher, H. D. (2017). Dietary fiber and prebiotics and the gastrointestinal microbiota. Gut Microbes, Vol. 8, No. 2, pp. 172-184.
    DOI: 10.1080/19490976.2017.1290756
  2. Courage, K. H. (2015, Mar 23). Fiber-Famished Gut Microbes Linked to Poor Health. Scientific American.
  3. Caballero, B., Allen, L., Prentice, A. (2005). Dietary Fiber: Physiological Effects and Effects on Absorption. In Encyclopedia of Human Nutrition, 2nd ed., Vol. 1, pp. 572-590. Elsevier.