There are two types of fiber, insoluble fiber and soluble fiber. Insoluble fiber adds bulk to feces because it is not digested, and also because it absorbs water. Insoluble fiber may help protect against cancer of the colon. Insoluble fiber does this either because it dilutes cancer-causing bile acids, or because it moves feces out of the colon more quickly. Soluble fiber dissolves in water and is degraded by bacteria in the colon.
Soluble fiber forms a bulky gel in the colon which regulates the flow of waste materials.
Psyllium, one type of soluble fiber, is used as an herbal detoxifier in many cleansing programs. Psyllium has been researched for its effect on both constipation and transit time. A group of people 65 years of age and older were given 24 g of psyllium a day for one month. The psyllium decreased transit time from 53.9 hours to 30 hours. Constipation is often a symptom of a toxic body and it can lead to other health problems such as hemorrhoids, diverticular disease, and hiatal hernias.