Ignore “don’t wear sunscreen” influencers
Expert
Dr David Robert Grimes: cancer scientist, biostatistician, science writer
Claims
We should use less sunscreen in order to increase our immunity to cancer, according to British epidemiologist and diet app founder, Tim Spector
Reality
Tim Spector posted that vitamin D can regulate cancer immunity naturally, followed by statements that vitamin D and sunshine help mice survive melanoma. Therefore, he advocates that humans stop wearing sunscreen.
As Dr Grimes points out, our DNA converts most UV light into harmless heat energy, but a small percentage of UV escapes this line of defense, which could lead to melanoma. He wonders if we saw suntans (and burns) as signs of direct DNA damage instead of an aesthetically-pleasing result of a beach vacation, we would change our views on this practice.
Sunscreens effectively reduce cancer risk associated with sun exposure—this includes on cloudy days, when UV is still present. SPF 15 blocks out 93% of UV, while SPF 50 blocks 98%.
Also, humans are not mice, and any research shared as “proof” that something bad for rodents will be bad for us should always be viewed skeptically.
Despite an avalanche of supplement-pushers long evangelizing vitamin D as a nigh-on-universal panacea, well-designed trials and meta-analysis have found no evidence of an impact on mortality, or indeed many of the other purported benefits that initial speculation suggested. Nor is there any reliable evidence that application of sunscreen inhibits vitamin D production in skin, precisely because doses needed for its production are relatively miniscule.
Bottom line: wear sunscreen daily.
