Meat Linked to Colon Cancer

Posted: March 1, 2005

A major American Cancer Society study finds people who reported the highest consumption of red and processed meat had a significantly higher risk of colorectal cancer than those who reported the least consumption.

The study of nearly 150,000 Americans, the largest and most comprehensive to date, adds substantially to previous evidence linking highest consumption of red and processed meat to intestinal cancer. The report was published in the Jan. 12, 2005 issue of the Journal of the American Medical Association (JAMA).

What counts as high consumption?
For red meat, prolonged high consumption was described as at least three ounces daily for men and two ounces daily for women over a period of 10 years. For processed meat, it meant at least one ounce per day five to six days per week for men and two to three days per week for women.

Three ounces is approximately equal to the amount in one large fast-food hamburger. A piece of bologna weighs one ounce; two slices of cooked bacon weigh a little more than one-half an ounce.

For the study, 148,610 adults aged 50 to 74 years residing in 21 states provided information on meat consumption in 1982 and again in 1992/1993 while enrolled in the Society’s Cancer Prevention Study II (CPS II) Nutrition Cohort.

The study found those who ate the most red meat in both questionnaires, 10 years apart, were 30 percent more likely to develop colon cancer than those who ate little or no red meat. Those who ate the most processed meat were 50 percent more likely to develop colon cancer.

The colorectal cancer risk posed by prolonged consumption of red and processed meats is similar or somewhat smaller than the risks associated with other lifestyle factors, such as physical inactivity and obesity.

The study did not directly examine mechanisms at the root of the association. Other studies have postulated that iron in red meat, carcinogens produced by cooking at high temperatures, fat in meat and/or salt or nitrates/nitrites in processed meat could be responsible for the increased cancer risk.

“The American Cancer Society’s guidelines on nutrition and physical activity currently recommend limiting consumption of red meat and choosing smaller portions and leaner cuts as ways to reduce the risk of colon cancer,” said Stephen F. Sener, M.D., an Illinois surgeon and the Society’s national volunteer president. “The study reinforces the importance of consuming a mostly plant-based diet for reducing the risk of cancer.”

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