Do sunscreens cause cancer? Probably not but the sun most definitely does. Therefore, to me the choice is easy: wear sunscreen!
Is it logical to stop using a prophylactic (a medicine or course of action used to prevent disease ) against an obvious and known source of mutagenic radiation (the sun) that has been shown to cause different forms cancer in innumerous studies because one is afraid to get cancer from a compound contained in that very prophylactic?
Many peddlers of “natural” sunscreens rely on the oft-cited study by Schlumpf et al. 2001, where rats were fed astronomical amounts of the compound oxybenzone (the compound that helps protect you from the sun’s rays). I repeat that: The rats were FED the compound and in ASTRONOMICAL amounts. How would you feel if you were fed large volumes of shampoo for example? I would guess that you would feel quite bad. Being fed shampoo is different from putting shampoo on your head.
In the same study oxybenzone was also applied to the skin of the rats and the compound was also investigated in in vitro experiments (experiments on cells).
Schlumpf et al. found that oxybenzone had estrogenic properties (that the compund was potentially carcinogen). As mentioned above the concentrations were emormous and not relevant to what humans are exposed to when wearing sunscreen. Direct transfer of results from in vitro studies and studies on other organisms like rats to humans can be very problematic and has to be done with extreme care. We are different organisms and function differently (see my article on the link between Deodorants and Cancer for a comment on that).
I did not manage to find any well documented study that showed adverse effects to humans by sunscreens regarding cancer risks. However some people might get contact allergies from sunscreens and there are alternatives on the market for sensitive skin.
I would like to cite a recent review on the topic by Burnett et al. 2011**:
The overwhelming majority of available data is drawn from studies conducted using antiquated sunscreen formulations. Nonetheless, our research revealed that topical use of sunscreen protects against squamous cell carcinoma, does not cause vitamin D deficiency/ insufficiency in practice and has not been demonstrated to adversely affect the health of humans.
Natural sunscreens like coconut oil do not cut it. The sun protection factor (SPF) of the relevant oils is somewhere between two and seven whereas a good sunscreen should have an SPF of more than 30. These “natural sunscreens” are utterly useless. Therefore using natural sunscreens might result in a much higher cancer risk because of their low SPF than if you wear conventional sunscreens.
However investigations into the compounds of sunscreens are warranted and should be taken seriously and always remember that the sun is a nuclear fusion reactor which radiation is highly mutagenic and carcinogen.
For a great article on the topic read neuroscientist and toxicologist Alison Bernstein’s article on sunscreen on Fitness Reloaded:
Slatter on that sunscreen, slap on a hat, sit in the shade, and stay healthy, young looking and fabulous!
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*In vitro and in vivo estrogenicity of UV screens. By: Schlumpf, M; Cotton, B; Conscience, M; et al. Conference: SETAC World Congress Location: BRIGHTON, ENGLAND Date: MAY 21-25, 2000. ENVIRONMENTAL HEALTH PERSPECTIVES Volume: 109 Issue: 3 Pages: 239-244 Published: MAR 2001
**Current sunscreen controversies: a critical review. By: Burnett, Mark E.; Wang, Steven Q.. PHOTODERMATOLOGY PHOTOIMMUNOLOGY & PHOTOMEDICINE Volume: 27 Issue: 2 Pages: 58-67 Published: APR 2011