Consumption of processed meat is associated with an increased risk of breast cancer, according to a meta-analysis.

Comparing the highest to the lowest category in the 15 studies included in the analysis, processed meat consumption was associated with a 9 percent higher breast cancer risk. Investigators did not observe a significant association between red (unprocessed) meat intake and risk of breast cancer.

Lead author Dr. Maryam Farvid of the Harvard T.H. Chan School of Public Health said, "Previous works linked increased risk of some types of cancer to higher processed meat intake, and this recent meta-analysis suggests that processed meat consumption may also increase breast cancer risk. Therefore, cutting down processed meat seems beneficial for the prevention of breast cancer."

Two studies evaluated the association between red meat and breast cancer stratified by patients' genotypes regarding N-acetyltransferase 2 acetylator. (Differences in activity of this enzyme are thought to modify the carcinogenic effect of meat.) The researchers did not observe any association among patients with either fast or slow N-acetyltransferase 2 acetylators. The study appears in the International Journal of Cancer.