Canadian research suggests that high coffee consumption levels may reduce the risk of breast cancer among women with BRCA1 gene mutations. A matched case-control study published in the International Journal of Cancer examined the association between coffee consumption and the risk of breast cancer among 1`690 high-risk women with BRCA1 or BRCA2 mutations. The odds ratios for breast cancer among BRCA mutation carriers who drank no coffee, one to three cups, four to five cups, or six or more cups of coffee were 1.00, 0.90, 0.75, and 0.31, respectively. When the women were stratified by mutation status, there was a significant protective trend for increasing caffeinated coffee consumption among women with a BRCA1 mutation. The authors say that coffee is an essential source of phytoestrogens, which may have chemoprotective effects. The mechanism by which phytoestrogens may beneficially influence breast cancer risk has predominantly been attributed to their structural similarity to endogenous estrogens and their ability to bind to estrogen receptors. Coffee consumption has been associated with a higher level of circulating sex hormone-binding globulin, which decreases bioavailable estrogen levels, they say.