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Posts Tagged ‘nanoparticles’

Do Sunscreens Cause Cancer? Are they safe? Notes from a San Francisco Bay Area Dermatologist

Tuesday, July 13th, 2010

The latest question on patients’ minds this summer is the safety of sunscreen.  A few websites have posted articles scaring people into questioning whether or not they should use sunscreen.  The bottom line is that sunscreens protect us from skin cancer and here’s why:

What do we know?

Numerous studies have looked at this issue, and none have confirmed any link between sunscreens and skin cancer. Some researchers have speculated that since sunscreens allow users to stay out in the sun longer they may increase the risk of skin cancer.  There have also been worries about physical sunblocks zinc oxide and titanium dioxide nanoparticles (micronized).  The worry is that these may pose a danger if inhaled or absorbed through the skin.  A large National Institutes of Health (NIH) funded study found minimal skin absorption of titanium nanoparticles and this has been confirmed by other studies.  It is possible that inhaled nanoparticles may be risky.  So if you use a spray sunscreen keep it away from your face (spray on your hand and rub in) or hold your breath when you spray.

We do know that the sunscreens help prevent skin growths called actinic keratoses.  These are rough scaly patches that can develop into squamous cell cancer.  There  is less evidence that sunscreens protect against melanoma and basal cell cancer.  This may be because these two cancers are strongly linked to sunburn.  Your risk of melanoma doubles if you have had five or more sunburns at any  age or from just one blistering sunburn before the age of 20.  Basal cell cancer seems also to be linked to  the  amount of freckling and number of burns.  In other words excessive sun exposure definitely causes cancer!!

Given that we know the sun can cause cancer and the evidence is nonexistent that sunscreens cause cancer common sense should prevail. Use sunscreen!

Are sunscreens safe for the environment?

Unfortunately sunscreens are bad for the ocean environment!  They come off in the water and settle down to the coral reefs blocking vital UV radiation. What can you do?  I am a huge proponent of  light weight wetsuits and  UV protective rash guards used for surfing.  I always wear one when I snorkel or windsurf. It is easier to put one of these on your kids and yourself than to deal with suncreening your whole body and reapplication after swimming.  They come in cute colors and styles and are widely available.  You can bolster their UV blocking abilities by washing with SunGuard or a similar product.  They claim they are effective up to 20 washing  cycles or swimming dips!  Apply your sunscreen to your face and hands and cover up  the rest with UV protective clothing!! You save your skin and the ocean!

 

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