High Fiber Diet

Fiber and Colon Polyps/Cancer

Colon cancer is a major health problem.  This disease is most common in Western cultures.  It is not seen very often in rural African cultures.  Usually, colon cancer starts out as a colon polyp, usually a benign mushroom-shaped growth.  In time it grows, and in some people it becomes cancerous.  Colon cancer is usually always curable if polyps are removed when found or if surgery is performed at an early stage.  It is now known that people can inherit the risk of developing colon cancer, but diet is important, too.  As noted, there is a very low rate of colon cancer in residents of countries where grains are unprocessed and retain their fiber.  It seems that in the Western world, cancer-containing agents (carcinogens) remain in contact with the colon wall for a longer time and in higher concentrations.  So, a large bulky stool may act to dilute these carcinogens by moving them through the bowel more quickly.  Less carcinogenic exposure to the colon may mean fewer colon polyps and less cancer.  A very current review of the entire world’s literature on the effect of fiber on colon polyps and cancer prevention has shown rather clearly that for every 10 grams of fiber added to the diet, there is a 10% reduction in incidence of cancer.  So the recommended 30 gram fiber diet would result in a 30% less chance of getting these tumors.

There are also substances produced in the colon by the good bacteria that seem to retard certain pre-cancer factors from developing.  They are called short-chain fatty acids (SCFA).  See above for description of SCFAs.  A high fiber diet increases these substances.  So, the combination of dietary fiber and the production of short-chain fatty acids have a clear health benefit.