Studies have long linked the consumption of red meat with an increased risk for colon cancer. Now, a new report suggests that white meats -- poultry or fish -- can also boost the risk of colon cancer.

"There is evidence of an excess risk of colon cancer for higher intakes of both red meat and white meat," conclude Drs. Pramil Singh and Gary Fraser of the Center for Health Research at Loma Linda University in California. Their report is published in the American Journal of Epidemiology.

The authors examined data from the ongoing Adventist Health Study, which for the past 20 years has contrasted the diet and lifestyle of over 34,000 California Seventh Day Adventists with their unfolding medical histories. Each of the participants in the study has agreed to fill out periodic detailed questionnaires, including 55 questions on various food preferences.

Singh and Fraser compared the dietary patterns of each of the subjects to the group's 1977-1982 incidence of colon cancer (a total of 157 cases).

They report that "the strongest risk factor (for colon cancer) among the food variables... was found for total meat intake." This association held true regardless of whether the meat-lover preferred white or red meats. For example, individuals who ate red meat once per week had a 38% higher chance of colon cancer compared with those who abstained from red meat, while those who preferred white meat had a 55% higher risk, compared with those who did not eat poultry or fish.

These risks rose with the amount of meat consumed. The authors say that subjects who ate either red or white meat over 4 times per week had double or triple the colon cancer risk of those who did not.

One food group -- legumes -- can be linked to a decreased risk of colon cancer. The researchers say the consumption of foods such as beans, peas, and lentils seemed to counteract the carcinogenic effects of red meat consumption. But this beneficial effect was not observed in legume-eating individuals who also consumed large amounts of white meat, however.

Singh and Fraser believe their findings "suggest the presence of factors in all meats that contribute to colon carcinogenesis." Those carcinogenic factors remain largely undetermined, although the researchers suspect that the byproducts of cooking, or ingredients used in curing and salting, may play some role. The researchers also suggest that the consumption of high-fiber legumes may help dilute the concentration (and effect) of meat-derived carcinogens within the colon.

SOURCE: American Journal of Epidemiology 1998;148:761-774.