Studies on red and processed meat consumption with breast cancer risk have generated inconsistent results. An International Journal of Cancer analysis has now examined all published studies on the topic.

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

"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," said lead author Dr. Maryam Farvid, of the Harvard T.H. Chan School of Public Health.