Women with BRCA1 gene mutations, which confer a high risk of developing breast cancer, might decrease their risk by drinking a lot of coffee, according to a multicenter team of investigators.

Dr. Steven A. Narod, of the University of Toronto, Ontario, and colleagues examined the association between coffee consumption and the risk of breast cancer among 1690 high-risk women with BRCA1 or BRCA2 mutations.

The study included women from 40 clinical centers in four countries. A self-administered questionnaire was used to assess the average lifetime coffee consumption.

The likelihood of developing breast cancer among BRCA mutation carriers who drank 1 to 3 cups of coffee daily, 4 to 5 cups, or 6 or more cups was reduced by 10 percent, 25 percent and 69 percent, respectively, compared to those who drank no coffee, according to the report in the International Journal of Cancer.

When the investigators classified the women by mutation status, they found significant protection from coffee for women with a BRCA1 mutation, but not for carriers of a BRCA2 mutation.

The investigators note that coffee is an important source of phytoestrogens, which may have protective effects.

“The mechanism by which phytoestrogens may beneficially influence the risk of breast cancer has predominantly been attributed to their structural similarity to endogenous estrogens and their ability to bind to estrogen receptors,” Narod and colleagues explain.

SOURCE: International Journal of Cancer, January 2006.