Coffee's Hidden Cancer Fighters

Coffee doesn't just kick-start the morning. New research shows that a cup of black coffee may also wake up the immune system, fortifying the body’s natural cancer-fighting agents.

Take, for example, a new study by researchers affiliated with Harvard University, which found that a spike in caffeine consumption correlated with a lower risk of basal cell carcinoma, a form of skin cancer that affects nearly 2.2 million Americans and is responsible for roughly 80 percent of all nonmelanoma cancer instances nationwide, according to the American Cancer Society.

In the study, the benefits of drinking coffee, surprisingly, broke down starkly along gender lines: The risk for women who drank more than three cups of caffeinated coffee every day was 21 percent lower than women who had less than one cup a month, whereas men showed only a 10 percent lower risk. Researchers don’t currently have a reason to account for that divide. Both groups were compared with people who drank coffee less than once a month. And there’s even good news for those who count themselves among the abstainers: The same effects were shown in chocolate, cola and tea.

“With this particular form of cancer, our research shows that it’s the caffeine in the coffee that’s probably responsible for the risk reduction,” says Jiali Han, an epidemiologist and an associate professor at Harvard Medical School. “We think that’s because caffeine plays a role in the process of apoptosis—cell death, essentially—so there is a biological rationale.”

That may also explain a recent study published in the Journal of the National Cancer Institute that spanned two decades. It found that men who drank six or more cups of coffee daily had an 18 percent lower risk of developing prostate cancer than men who drank no coffee at all. And these men were 60 percent less likely to develop metastatic prostate cancer. Cut the intake down to one to three cups, and men still managed to lower their lethal prostate cancer risk by 29 percent.

And there’s more: A 2007 Swedish study, for instance, found that an increase of two cups of coffee daily was associated with a lower risk of liver cancer by 43 percent. Studies like these add to a growing body of research that has already shown coffee drinkers may live longer, on average, and show a lower risk of Alzheimer’s disease, dementia, gout, type 2 diabetes and Parkinson’s. But don’t take that as a cue to become mayor of the Starbucks drive-thru.

We think that’s because caffeine plays a role in the process of apoptosis—cell death, essentially—so there is a biological rationale."

“None of the studies that report decreased risk in coffee drinkers actually show that drinking coffee was the reason,” says James Lane, professor of medical psychology and director of the Psychophysiology Laboratory at Duke University Medical Center in Durham, N.C. “The studies never establish a cause-effect for the association.” And that limitation is more important than some people might think.

“Coffee is often said to contain antioxidants that could fight cancer, but there is no scientific evidence that these compounds influence oxidative stress in humans,” Lane says. “Experimental studies must be conducted to determine the effectiveness of a new treatment, and many times those studies fail to find a beneficial effect.”

On the other hand, for people who count on java first thing—and maybe second and third thing—in the morning, it’s not necessarily a habit they need to worry about breaking, either. “The literature on coffee and cancer, as well as that on coffee and cardiovascular disease and diabetes, suggests that it’s not harmful in terms of long-term health,” says Kathryn Wilson, a research associate at Harvard School of Public Health who led a recent study linking coffee to a reduced risk of prostate cancer. “So if people like drinking three or more cups per day, there’s no reason to stop.” Unless, of course, they have insomnia.