Although all of the genetic and environmental factors are important to consider, the overwhelming evidence is that breast cancer is related to lifestyle.  The following paragraphs outline the negative impact and positive impact on breast cancer of several common lifestyle related issues.

Post-menopausal Obesity Increases Risk:  Despite the evidence on the protective effect of pre-menopausal obesity on pre-menopausal breast cancer, the evidence that obesity increases the risk of post-menopausal breast cancer is very clear and not debatable.  Some have suggested that tumors are harder to find by physical exam and mammography in obese women.  This theory has largely been disproved in studies looking at mammography sensitivity and specificity, as well as studies looking at breast exam diagnosis in obese patients.  If the correlation between obesity and cancer mortality is entirely causal, some scientists even estimate that an overweight condition and/or obesity now may account for one in seven of cancer deaths in men and one in five in women in the US.

Alcohol:

Exercise

Supplements:  Americans spend billions of dollars on vitamins and mineral supplements.  Recent large studies, however, have demonstrated that these pills and capsules do not decrease the risk of many types of cancer.  One explanation is that as long as one is not deficient of any particular vitamin or mineral, ingestion of super-normal levels of supplements does not help.  Many women have low levels of vitamin D, and some data have shown that increasing its level (whether in a pill or by sun exposure) can protect somewhat against future breast cancer.  In our opinion, botanical dietary supplements derived from green tea extracts represent a potentially widely available method for reducing the risk of breast cancer.  Next to water, tea is the most widely consumed beverage in the world, and its ingestion in reasonable doses is considered safe.  Many population observation reports have shown that green tea may decrease the risk of breast cancer.