Yet another experiment was reported on those long suffering mice – this time at the American Association for Cancer Research Annual Meeting.
Why this is a big deal is that it was the first time we can say “yes this sunscreen can protect you against melanoma” noted lead researcher Christian Burd of the team from Ohio State University.
Conventional sun screens protect against the shorter wavelength ultraviolet light (UVB) which is known to cause skin cancer as a whole. In this experiment they took genetically engineered mice (modified to have skin like humans), painted them with a variety of SPF 30 sunscreens, then zapped them with the equivalent of a weeks worth of sunbathing at a time (it doesn’t say if they sat around the ool or went to the beach).
The significance is that this showed it protected the mice specifically from melanoma – which is the nastiest (most aggressive) of the various skin cancers, whose prevalence has doubled in the last 30 years.
Sun Exposure Science
One reservation about this study was it didn’t include the longer wavelength, UVA, which originally, though it penetrates deeper into the skin (and has a general immunosuppressive effect on the body as a whole), was not thought to be as harmful as UVB. But now it is found that it does have a role in skin cancer by damaging DNA, but by forming free radicals rather than directly screwing with the components of the DNA molecule like UVB does.
Newer sunscreens are starting to contain ingredients that protect against UVA.
In terms of carcinogenic effect, intermittent episodes of sunburn/over-exposure seem far more harmful than long-term exposure.
And the best protection is melanin – the pigment in the skin that is formed in response to sun exposure and that makes you tan – if you are not like me with that delicate Anglo-Saxon skin that goes red, peels off and leaves you as vulnerable again as any naked mouse.
