Red meat increases the incidence of breast cancer in young women

Farvid et al report in BMJ findings from their study of responses to a questionnaire of 88,803 premenopausal women from the Nurses’ Health Study II regarding their diet that were completed in1991.  Their analysis found 2830 cases of breast cancer during 20 years of follow-up.

Higher intake of red meat was associated with an increased risk of breast cancer overall (relative risk 1.22, 95% CI 1.06 to 1.40). However, higher intakes of poultry, fish, eggs, legumes, and nuts were not related to breast cancer overall.

When the association was evaluated by menopausal status, higher intake of poultry was associated with a lower risk of breast cancer in postmenopausal women (0.73, 0.58 to 0.91) but not in premenopausal women.

In estimating the effects of exchanging different protein sources, substituting one serving/day of legumes for one serving/day of red meat was associated with a 15% lower risk of breast cancer among all women (0.85, 0.73 to 0.98) and a 19% lower risk among premenopausal women (0.81, 0.66 to 0.99). Also, substituting one serving/day of poultry for one serving of red meat lower the overall risk of breast cancer (0.83, 0.72 to 0.96) and a 24% lower risk of postmenopausal breast cancer (0.76, 0.59 to 0.99). Furthermore, substituting one serving/day of combined legumes, nuts, poultry, and fish for one serving/day of red meat was associated with a 14% lower risk of breast cancer overall (0.86, 0.78 to 0.94).

The authors conclude that higher consumption of red meat by young women is a risk factor for breast cancer.  They also state that replacing red meat with a combination of legumes, poultry, nuts and fish may reduce the risk of breast cancer.