Breast Cancer Risk Linked to Meat Consumption

In the Nurses’ Health Study of 90,000 pre-menopausal women followed for 20 years, those who ate 1.6 servings of meat per day had a 22 percent increased breast cancer risk, compared with women who took in 0.2 servings per day (British Medical Journal, June 10, 2014). The authors suggest that the mechanism may be that high meat intake increases insulin-like growth factor-1 that stimulates tissue growth and tumor progression.

Substituting one serving per day of legumes, nuts, poultry or fish for one serving per day of red meat was associated with a 14 percent lower risk of breast cancer. Eating poultry, fish, eggs, legumes or nuts were not associated with increased breast cancer risk. In post-menopausal women, a high intake of poultry was associated with reduced risk for breast cancer.

A pooled analysis of eight earlier studies found no association between intake of red meat and risk of breast cancer (Int J Epidemiol, 2002;31:78-85). However, these studies did not separate what a woman ate early in life and late in life. The Nurses' Study is different because it follows women's diets as they age. This study suggests that the time from a woman's first period to her first pregnancy may the most important time for restricting red meat to reduce risk of breast cancer.

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