Digestion of Fiber
Many types of soluble fiber can act as prebiotics, a food fiber that grows in plants that feed healthy bacteria. Onions, garlic and bananas are examples of where prebiotic soluble fiber can be found. Soluble fiber passes through the small intestine relatively unchanged until it reaches the colon, or large intestine, which is the part of your digestive system responsible for absorbing water from indigestible parts of food. It is here where fermentation of fiber occurs. Fermentation is the action of bacteria on prebiotic fiber, producing gases and short-chain fatty acids.
When the friendly bacteria called probiotics, bacteria that keeps disease-promoting microorganisms from infecting your colon, ferments or digests the probiotic fiber, it produces many nutrients that help keep your colon healthy. The products of the fermentation stimulate your bowels, retain water in your stool and bulk up your stool. Insoluble fiber passes through the colon relatively unchanged and helps bulk your stool.
Benefits of Fiber
Fiber has many health benefits. The main function of fiber is to keep your digestive system healthy and working properly. Fibers that are fermented, or prebiotics, provide energy for the cells in your colon, promote the growth of good bacteria and help with regularity, insulin sensitivity and keeping your immune system healthy. Besides aiding digestion, soluble fiber is associated with improving blood sugar levels by slowing down the absorption of sugar, and lowering LDL cholesterol levels by absorbing the cholesterol, preventing it from entering your bloodstream.
Insoluble fiber helps improve your bowel movements and prevents constipation by softening and increasing the weight and size of your stool, making it easier to pass. A diet high in these types of fiber may reduce the risk of developing heart disease and some types of cancer. In addition, foods high in fiber can make you feel fuller longer so that you are less likely to overeat.
Lesson Summary
In summary, the main function of fiber is to keep your digestive system healthy and working properly. Even though enzymes in your small intestines cannot digest dietary fiber, fermentable fiber, also called prebiotics, is fiber that is resistant to digestion in your small intestines but is broken down partially or completely by bacteria in the colon, or large intestine, which is the part of your digestive system responsible for absorbing water from indigestible parts of food.
Fermentation is the action of friendly bacteria called probiotics on prebiotic fiber. When the friendly bacteria ferment or digest the prebiotic fiber, a food fiber that grows in plants that feed healthy bacteria, it produces gases, short-chain fatty acids and many nutrients that help keep your colon healthy.
Learning Outcomes
Following this video lesson, you should be able to:
- Identify the main function of fiber and the two types of fiber
- Describe the role of prebiotics and probiotics in digesting fiber
- Explain what fermentation is and its benefits in the body
