Colon cancer is one of the three leading causes of cancer deaths in the United States—some 50,000 people die from it each year. You can sharply cut your odds of getting colon cancer by eating more fiber. That’s because fiber increases the bulk of your stool and makes it pass through your colon more quickly. All sorts of toxic stuff passes through your colon: your own wastes, bile acids, pesticides, food additives and preservatives, heavy metals, and chemical pollutants of all sorts. One of the jobs of your stool is to move this stuff through and out of you quickly. That way, anything that might cause cancer spends as little time as possible in contact with your colon. Because a high-fiber diet speeds the transit time for your food, it cuts the amount of time dangerous substances spend in your body, which cuts your risk of colon cancer.
Although many studies have shown that people who eat a high-fiber diet have a lower rate of colon cancer, we still don’t know for sure that the fiber alone helps prevents the cancer. People who eat more fiber also tend to eat less fat, drink less alcohol, and smoke less, so the fiber connection isn’t as clear-cut as you might think. Even so, the National Cancer Institute recommends a high-fiber, low-fat diet to help prevent colon cancer. Fiber in the diet may also play a role in preventing breast, cervical, and lung cancer, but here too we can’t say for sure that it’s the fiber alone that does the trick.
