Diet and breast cancer.

Clarification of the role of diet in breast cancer pathogenesis is important in order to identify modifiable risk factors on which to focus prevention efforts. Excess weight and weight gain in adult life are related to higher risk of postmenopausal breast cancer, and weight loss after menopause is associated with substantially reduced risk. Even moderate alcohol consumption contributes considerably to excess breast cancer risk, which can likely be mitigated with adequate folate intake. Diet during early life may play a substantial role in later cancer risk, but data are limited. In addition, physical activity and the prevention of weight gain can improve survival after a breast cancer diagnosis.