in humans why are fibers not digested?
Although it is recommended that people consume a high fiber diet, fiber is unable to be digested by people. Ruminants, such as cows have a specially adapted stomach that is able to digest the cellulose in the plants they consume. We lack the enzymes necessary to do this. However, fiber which is soluble, binds to bile in the small intestine making it less likely to be absorbed into the bloodstream. This lowers cholesterol which benefits the cardiovascular system. Insoluble fiber, is able to absorb water which adds bulk to the feces and eases the process of defecation. Soluble fiber is fermented by bacteria in the intestine producing gases as well as compounds needed by the body. Fiber in the diet has been linked to a decrease in the development of certain cancers as well as diabetes.