Hold the Latte, Keep the Sun Screen

Craig Stoltz Health Guide
  • Anyone concerned about skin cancer will benefit from a quick reality check on recent news stories of a study suggesting caffeine and exercise may cut skin cancer risk. It's been widely reported with misleading headlines that could lead to some unwise behavior. 

    So: Let's take a look.

    Bottom line first

    A mixture of caffeine and exercise somehow improved the ability of mice to prevent sun-damaged skin cells from developing into cancer cells.  

    This study in 50 words or less

    Researchers exposed hairless mice to enough UV-B radiation to damage their DNA. Some mice got the equivalent of around two cups of coffee daily and exercised on a wheel for two weeks. Compared to "control" mice, the caffeine/exercisers' bodies were four times more successful at killing off precancerous cells.

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    Yes, but. . .

    THE EXPERIMENT WAS DONE ON MICE, NOT HUMANS. The list of studies conducted on mice, rats and other mammals that later fail to translate to humans could fill a phone book. The number that do carry over could fill a trim file folder. You just never hear about the failures. The press doesn't report "caffeine-exercise link disproven for skin cancer." That's not considered a story.

    So What Are You Going to Do About It?

    Nothing. Until this effect is confirmed in humans, there's nothing here to act on. But let's explore that more:

    ASSUMING the same cellular mechanism is proven in humans, the caffeine-and-exercise link would then need to be subjected to a randomized, placebo controlled clinical trial that followed subjects for years to see if it cut skin cancer risk.

    AND EVEN IF IT DOES THAT, the takeaway would essentially be: Use caffeine if you like, but don't start using it just as a skin cancer preventative. Exercise has been shown to reduce risk of various cancers, and has plenty of other important health benefits, so it's wise to do that even before results from this study are in.

    And regardless of any other findings, best practices for reducing skin cancer risk will likely remain unchanged: Use sunscreen whenever you're exposed to the sun; avoid peak sun times; have a regular skin checks by a dermatologist; do your own regular skin self-exams and report any changes to your doctor as soon as you notice them.
    Learn more

    Our site has an excellent explainer on how skin damage can turn into skin cancer, and how to prevent it.

    Check in with our expert dermatologist, Dr. Kevin Berman to ask a question, offer a comment or see what else he has had to say on the topic of skin cancer and prevention. You might want to start with this excellent SharePost in which he explains the mechanism by which skin cancer develops.

    And take a look at this video explaining a leading-edge treatment that, surprisingly enough, uses light to reduce the chance that precancerous growth will develop into cancer.
Published On: July 31, 2007