- Intact fiber (found in fruits, vegetables, whole grains and other plants or a mix of plants)
- processed fiber (extracted from plants or made in a lab)
Though all fiber is not equal, and they do not have identical effects on the digestive system, they are classified together on the Nutrition Facts labels. What you want to eat is minimally processed plant foods so you are getting what your body needs.
- Soluble: dissolves in water, then thickens or forms a gel
- Insoluble: does not dissolve in water and is left intact as it moves through the gastrointestinal tract.
- Fermentable: broken down by gut bacteria in the large intestines
- To prevent or treat constipation, look for both soluble and insoluble fiber to increase stool mass and stool frequency. Registered dietitians suggest: Insoluble has to be relatively coarse to be effective. The coarseness irritates the lining of the bowels, which stimulates water to be secreted. And it’s this water that leads to the softening and bulking effect on stool. Soluble is a gel-forming fiber, able to hold moisture in the large bowel.
- To lower cholesterol, look for soluble, gel-forming fibers. As the fiber moves down your intestine, it absorbs water from partially digested foods, making the mass thicker and more sludge-like. That traps the bile acids our bodies make to break fat down, preventing fat reabsorption and instead eliminating them through the stool. To replace the excreted bile acids your liver must use cholesterol, making it less available in your blood stream.
- To manage blood sugars, look for soluble fiber. Once again by thickening the mix of food traveling down the intestines, absorption of nutrients and glucose is reduced.
- To manage your weight, select whole foods with fiber. These foods tend to be more filling than low-fiber foods, and they keep your fuller longer, so you’re likely to eat less.
If you are getting a balanced plan that includes a mix of minimally processed fruits vegetables, beans, whole grains and starchy vegetables, you are getting all you need.