Good news for women who can't quite bring themselves to go vegetarian, but don't mind giving up burgers and steaks: A new study finds red meat may increase breast cancer risk, while substituting poultry may lower it.
The study, published in the International Journal of Cancer, looked for links between meat consumption patterns and the incidence of breast cancer in 42,012 women from the U.S. and Puerto Rico who were followed for an average of 7.6 years.
During that period, 1,536 invasive breast cancers were diagnosed. The researchers, led by Columbia University epidemiologist Jamie J. Lo, found that women who consumed the most red meat — a quarter of a pound or more per day — had a 23% higher risk of invasive breast cancer compared with women who consumed the lowest amount. Meanwhile, women with the highest consumption of poultry had a 15% lower risk than those with the lowest consumption.
Using mathematical models to add or substitute meats, the researchers found breast cancer risk was further reduced by swapping poultry (chicken, turkey, hens, duck, goose or game birds) for red meat (beef, veal, pork, lamb and game meat).
The associations didn't change when the researchers made adjustments for factors that could skew the findings such as family history of breast cancer, obesity, physical activity, and alcohol consumption.
The magnitude of the effects, good or bad, on breast cancer risk was relatively small. And the new study is just the latest to weigh in on an unsettled area of research. While many studies suggest vegetarian diets are a good strategy to ward off a number of cancers, particularly colon cancer, the association between red meat consumption and breast cancer risk has been inconsistent.
Why might red meat make a difference? Lab and animal studies have found that iron, fat, and certain acids found in red meat can increase tumor formation. Another theory involves the cancer-causing byproducts that result from cooking or grilling red meat at high heat.
Poultry's possible protective effect is even more speculative.
"While the mechanism through which poultry consumption decreases breast cancer risk is not clear," senior author Dale P. Sandler of the National Institute of Environmental Health Sciences said in a press release, "our study does provide evidence that substituting poultry for red meat may be a simple change that can help reduce the incidence of breast cancer."