A meta-analysis showed that the relative risk for breast cancer was 6% higher in people who consumed the most unprocessed red meat than in those who consumed the least; for processed meat, the relative risk was 9% higher (Int J Cancer. 2018;143:2787-2799).

Another study showed that postmenopausal women who consumed large amounts of processed meat had a 64% higher risk for breast cancer than postmenopausal women who consumed no processed meat (Br J Cancer. 2007;96:1139-1146).

On a positive note, though, data from the Nurses’ Health Study II showed that when adolescents replaced one serving of red meat a day with poultry, fish, legumes, or nuts, risk for overall breast cancer decreased by 16% and risk for premenopausal breast cancer decreased by 24% (Int J Cancer. 2015;136:1909-1920).