Coffee, exercise and skin cancer

According to several media outlets today, doing regular exercise and drinking coffee protects you against skin cancer.

But before you jog off to the nearest coffee shop and back, let’s have a look at the science behind these claims.

The study, carried out by a group of researchers in the US, looked at the skin cells of mice that had been given caffeine, or allowed to run on an exercise wheel, or both, while being exposed to ultraviolet light.

In particular, they looked for signs of a process called ‘apoptosis’ (often referred to as ‘cell suicide’). This occurs when cells sense they are damaged, and so self-destruct to avoid developing into cancer.

The researchers reasoned that, if apoptosis levels went up during the experiments, it meant that the skin cells were dealing with any damage from UV light more effectively, and protecting the mice against cancer.

What the team found was that both exercise and caffeine increased the rates of apoptosis in the skin cells of the mice.

The interesting result was that the combined effect of the caffeine and exercise was much higher than either of them alone, suggesting that the effects were acting synergistically (i.e more than just the sum of the two effects combined), and that there was some unknown biological process at work.

Now, let’s be clear here: the researchers did not look at whether the mice actually got skin cancer. The mice were special ‘hairless’ albino mice, bred for research on skin cells and wound healing. And the research team used UV ‘B’ radiation – not UV ‘A’… and the latest research on skin cancer seems to be suggesting that it is UVA that’s the culprit in most skin cancers.

So it is extremely doubtful that there is any meaningful lifestyle advice you, as an individual, can draw from this single piece of research.

Skin cancer rates are on the rise in the UK, mainly because people do not take proper care in the sun. Indeed, some have estimated that 8 out of ten skin cancers could be prevented. But research like this propagates the idea that there are ‘things you can do’ that make lying in the sun safe.

This is a shame – because most of the evidence we have suggests that by far the best way to reduce your risk of skin cancer is to follow the SunSmart advice:

• Spend time in the shade between 11 and 3
• Make sure you never burn
• Aim to cover up with a t-shirt, hat and sunglasses
• Remember to take extra care with children
• Then use factor 15+ sunscreen