Sunscreens are supposed to protect our skin from the sun’s UV rays, thereby lowering the risk for skin cancer, especially the deadly melanoma. Now come these claims that sunscreens actually do just the opposite. Let us examine the evidence.
Many sunscreens contain zinc oxide and titanium oxide, compounds that are supposed to block the UV rays. Some studies suggest, however, that these compounds produce free radicals when exposed to sunlight, leading to cell damage.
In 2000, Swedish researchers looked at 571 people with cutaneous malignant melanoma and compared them to 913 people without skin cancer (healthy controls). The analysis showed that the melanoma incidence was significantly associated with regular sunscreen use.
Many people are quick to conclude that it was the sunscreen that caused the melanoma. However, the researchers emphasized on the following key points:
- The study was conducted during the 1990s when the sun protection factor (SPFs) for sunscreens was generally low. The SPF used by the study participants ranged from 2 to 25, with a median of 6.
- Those who used sunscreens reported to have stayed longer under the sun.
- The increased melanoma risk was especially significant among those who used products with SPF of 10 or lower and among men.
The study concluded
Our results are probably related mainly to earlier sunscreens of low SPF. They substantiate the hypothesis that sunscreen use, by permitting more time sunbathing, is associated with melanoma occurrence.
A 2007 review by French researchers gave the following information:
- Frequent sunscreen users are usually those with higher natural sensitivity to the sun.
- Sunscreen use led to longer exposure to the sun among people who did this intentionally in order to get a tan.
It seems that sunscreen use as such doesn’t increase the risk for melanoma. However, the tendency of people to stay longer under the sun, believing that their sunscreen provides them complete protection from UV rays does play a role in increasing the risk.
There have been changes in sunscreen labelling to give consumers more accurate and less misleading information about sunscreen. Especially important is the fact that the SPF of your sunscreen does not necessarily tell you how long you can stay in the sun. It depends on so many factors including skin type, geographic location, time of the day, and weather conditions.
In addition, a broad-spectrum sunscreen, one that filters UV A as well as UV B rays has been shown to “provide better protection from solar ultraviolet-simulated radiation and natural sunlight-induced immunosuppression in human beings.”
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