Diet in the epidemiology of cancer of the colon and rectum.

We examined the diets as reported in interviews of 256 white male patients with cancer of the colon and of 330 white male patients with cancer of the rectum. Controls were 783 patients with nonneoplastic, nondigestive system diseases distributed by age similarly to the colon cancer patients and 628 patients with nonneoplastic, nondigestive diseases distributed by age like those with cancer of the rectum. We found no increase in risk for cancer of the colon or rectum regardless of the amounts of beef or other meats ingested. However, we found an increase in risk of colon cancer with decreases in the frequency with which vegetables were eaten. A study of 214 females with cancer of the colon and 182 females with cancer of the rectum yielded similar results. The decrease in risk we found associated with frequent ingestion of vegetables, and especially cabbage, Brussels sprouts, and broccoli, is consistent with the decreased numbers of tumors observed in animals challenged with carcinogens and fed compounds found in these same vegetables.