You don't usually see it or taste it, but fiber works wonders for your body. Dietary fiber is a known cancer fighter found only in the cell walls of plant foods. For years, studies have pointed to the fact that increased fiber intake decreases the risk of colorectal cancer.
According to a study published in the New England Journal of Medicine (1999) this protective effect may be due to fiber's tendency to add bulk to your digestive system, shortening the amount of time that wastes travel through the colon. As this waste often contains carcinogens, it is best to removed it as quickly as possible.
The Journal of Clinical Nutrition (1999) reported that fiber may also help protect against breast cancer, an effect noted especially with consumption of whole grains and wheat bran. Studies indicate that that high amounts of fiber may also prevent breast cancer by binding to estrogen. When bacteria in the lower intestine break down fiber, a substance called butyrate is produced which may inhibit the growth of tumors of the colon and rectum as reported in the Journal of Oncology Research in 2000. Fiber may also have a protective effect against mouth, throat and esophageal cancers according to a study published in the International Journal of Cancer in 2001.
Most Americans only take in about 10-15 grams of fiber per day. However, studies have shown that to have a cancer preventing effect one needs about 30-35 grams per day. So what should we do? Eat more vegetables!