BMJ, 06/24/2014 > Evidence Based Medicine Clinical Article
Farvid MS, et al. – The aim is to investigate the association between dietary protein sources in early adulthood and risk of breast cancer. Higher red meat intake in early adulthood may be a risk factor for breast cancer, and replacing red meat with a combination of legumes, poultry, nuts and fish may reduce the risk of breast cancer.
Methods
- Prospective cohort study.
- Health professionals in the United States.
- 88 803 premenopausal women from the Nurses’ Health Study II who completed a questionnaire on diet in 1991.
- Incident cases of invasive breast carcinoma, identified through self report and confirmed by pathology report.
Results
- Authors documented 2830 cases of breast cancer during 20 years of follow–up.
- Higher intake of total red meat was associated with an increased risk of breast cancer overall (relative risk 1.22, 95% confidence interval 1.06 to 1.40; Ptrend=0.01, for highest fifth v lowest fifth of intake).
- 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; Ptrend=0.02, for highest fifth v lowest fifth of intake) but not in premenopausal women (0.93, 0.78 to 1.11; Ptrend=0.60, for highest fifth v lowest fifth of intake).
- 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/day of red meat was associated with a 17% lower risk of breast cancer overall (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) and premenopausal breast cancer (0.86, 0.76 to 0.98).