A recent study from Sweden published May 11, 2011 indicates that the risk of developing a certain type of breast cancer was significantly lower in women who drink at least 5 cups of coffee per day. According to the researchers at the Karolinska Institute in Stockholm, women who drank that much coffee were up to 57% less likley to develop ER-negative breast cancer than women who drank less than one cup per day.
Coffee contains a number of different phytoestrogens, which are plant-based chemicals that act like estrogens in the human body. Coffee has been shown to contribute to blood levels of a phytoestrogen called enterolactone, which is associated with a decreased risk of estrogen-receptor negative breast cancer.
The study doesn’t indicate that coffee can prevent breast cancer, but that women who consume a lot of it have a protective benefit from this type. Studies have also been conducted that indicate coffee has a protective effect against colorectal, endometrial, and and cancers of the head and neck.