The views expressed are those of the author(s) and are not necessarily those of Scientific American.
At first glance, this new droplet of research linking caffeine mixed with exercise to protection against skin cancer in mice seems like grounds for excitement. Mice who were fed the equivalent of one to four cups' worth of caffeine per day and also ran on their wheels showed nearly four times as much destruction of ultraviolet-damaged skin cells as sedentary, decaffeinated mice after two weeks [I will link to the paper, from Proceedings of the National Academy of Sciences, when it goes online]. Interestingly, the (premium) blend of coffee and exercise conferred more protection than the added effects of caffeine or exercise alone. The two things seem to be feeding on each other in some unknown way. I can already imagine the marketing campaign: "SPF 15, now with caffeine!" Then people will start making their own by squirting sunscreen into the coffee grinder. It could all get really gross. Of course, the normal caveats apply here: these are rodents, and we don't know how well this finding will translate to us, nor how much cancer protection a given amount of cell self-destruction might confer. And after a moment's percolation, I conclude that even if the effect holds for people, it is likely to be more of a comfort to coffee drinkers than a cancer cure. True, coffee drinking has yet to max out: 37 percent of 18- to 24-year-olds drink it, averaging 3.1 cups per day, according to National Coffee Association numbers. But at this stage, few of us need to be reminded that exercise is good for you, and coffee already has a mixed bag of potential health benefits (possible reduced risk of diabetes) and detriments (hypertension) that seems unlikely to sway anybody one way or the other, assuming they weigh the evidence. Even one of the researchers who identified the link between coffee and diabetes didn't advocate drinking more java, according to the kicker in this NYTimes piece from last year. It's still kind of a cool finding. If anything, maybe pharma could identify some caffeine-ish compound that conferred extra protection against skin cancer for those with a family history of it. But until then, keep using your (caffeine free) sunscreen, kiddies. (Drink deeper, if you like, from the Washington Post.)