Colon Cancer: A Fiber Fiasco?
Q. The news that fiber doesn't protect against colon cancer is discouraging, particularly for those of us who have gone to a lot of trouble to add fiber to our diets. What do we do now?
I agree with you. The recent news that eating fiber won't help prevent colon cancer is discouraging. But while the scientific findings are persuasive, I don't think they are the last word on the subject. I still recommend that you include plenty of fiber in your diet.
To recap, two studies published in the April 20 "New England Journal of Medicine" reached virtually the same conclusion: Adding fiber to the diet doesn't seem to prevent the recurrence of colon polyps, growths that can forecast colon cancer. The first study included 2,079 men and women over the age of 35 who previously had surgery for polyps in the colon. Half of this group were told to eat five to eight servings of fruits and vegetables daily -- an amount calculated to provide at least 18 grams of fiber for every 1,000 calories consumed. They also limited fat consumption to 20 percent of daily calories. The other half of the group didn't have to make any dietary changes. After four years, the rate of polyp recurrence among both groups was the same -- 39 percent.
The second study followed 1,429 men and women between the ages of 40 and 80 who also had surgery to remove colon or rectal polyps. Patients were randomly assigned to either a diet that was high (13.5g per day) or low (2g per day) in wheat bran fiber. After three years, both groups of patients had similar rates of polyp recurrence.
Despite these results, we still have persuasive evidence from observational studies done around the world that colon and rectal cancers are less common among people whose diets include large amounts of the fruits and vegetables that provide us with dietary fiber. In fact, researchers from the two published studies say it's possible you need even more fiber than what they gave the patients in their studies. We also have firm data showing that the higher the fiber content of your diet, the lower your risk of heart disease, diabetes, and, of course, obesity. Furthermore, the insoluble fiber in our diets prevents bowel problems, such as constipation, and promotes the health of the digestive system.
As for cancer prevention, regular screenings are most important in the fight against colon cancer. Removing polyps and early-stage cancers is extremely effective in halting the disease.
If I were you, I would continue with your high-fiber diet indefinitely. It is much more likely to help, rather than hurt you.