CBS - Can coffee kayo cancer? A provocative new study from Sweden showed that the risk of developing a particularly aggressive form of breast cancer was significantly lower in women who consume lots of coffee.
How much is lots? At least five cups a day. Women who drank that much were up to 57 percent less likely to develop ER-negative breast cancer than women who drank less than a cup a day, the study showed.
For the study - published online May 11 in Breast Cancer Research - researchers from the Karolinska Institute in Stockholm used questionnaires to track the health and habits of almost 6,000 women between the ages of 50 and 74.
No one knows for sure the exact nature of the link between coffee and a reduced risk of breast cancer. Coffee is known to contain many phytoestrogens, compounds that have estrogen-effects in the body, according to MSNBC.
But it's important to realize that the study didn't prove that coffee itself prevents cancer, only that woman who drink a lot of it are at lower risk.
Given the uncertainty, researchers say it's premature to recommend coffee to women worried about breast cancer.
"Before I would go to tell my neighbors to start drinking more coffee than they already do, I would like to know what is the biological mechanism at work here," study author Dr. Per Hal, professor of medical epidemiology and biostatistics at the institute, told HealthDay. "And that's not yet clear."