From The August 2000 Issue of Nutrition Science News

Low Fat, High Fiber Doesn't Cut Colon Cancer Risk

A comprehensive, prospective study has found that reducing fat and increasing fiber intake does not lower the chances of developing colon cancer. Arthur Schatzkin, M.D., Ph.D., of the National Cancer Institute in Bethesda, Md., studied 1,905 patients with an average age of 61 who previously had at least one colorectal polyp. Out of this group, 958 received intensive dietary counseling from registered dietitians and consequently reduced their mean fat consumption from 35.6 percent of calories to 23.8 percent and increased their fiber intake from 10 g/1,000 cal. to 17.4 g/1,000 cal. over the next four years. Control group diets remained fairly constant, with fat declining slightly from 36 percent to 33.9 percent of calories, and fiber intake edging up slightly from 9.5 to 10 g/1,000 cal.

Over the four years, almost 40 percent of both groups suffered a recurrence of polyps, most of which were small. There was no statistical difference between groups in recurrence of small, large or advanced polyps, or of colorectal cancer, which occurred in four controls and 10 people who had received dietary intervention.

This study has been interpreted to prove that diet cannot prevent colon cancer, but it should be noted that study participants had previously eaten a high-fat, low-fiber diet for an average of 61 years, and had already suffered from precancerous growths. The researchers also note that if the dietary changes affected only the growth of small polyps into large ones or the transformation of large polyps into invasive cancers, the benefits would not have been apparent in this study.

—The New England Journal of Medicine, 2000 Apr 20;342:1149-55.