Here Comes the Sun

It’s been a long cold winter (and spring) and everyone is ready for the warm, sunny, summer days!  Although the sunshine warms the weather and our spirits, some of those rays are UVA and UVB rays that may have both acute (burns) and chronic (cancers) effects on our skin and eyes, and may be even more dangerous to our children’s health. The American Cancer Society has coined the phrase “Slip, Slop, Slap, and Wrap” to remind us to follow the four key steps to protect ourselves and our kids against the sun’s harmful rays:
•    Slip on a shirt
•    Slop on sunscreen
•    Slap on a hat
•    Wrap on sunglasses

Topical sunscreens are recommended for children over 6 months old and for all adults.  Sunscreens are labeled for SPF, a grading system to quantify the degree of protection from UV rays.  An SPF-15 means a person who would normally be sunburned after 10 minutes in the sun would be protected for 150 minutes (10 x 15).  Higher SPF numbers don’t directly translate into greater protection: an SPF- of 45 triples the length of time of protection but does not triple the actual protection of SPF-15.  Suncreens with SPF-15 filter about 93% of the UVB rays; SPF-30 filters 97%; SPF-50 about 98%; and SPF-100 filters 99%.

Sunscreens contain substances that protect the skin from UV light.  Some of these substances are absorbed through the skin and may result in adverse health effects.  Because children have relatively larger surface area than adults, they may absorb relatively more of these substances.  Also, because children have less mature metabolisms than adults, they may clear these substances from their bodies more slowly than adults.

One common component of sunscreens, oxybenzone (or benzophenone-3), is known to be absorbed through the skin, is associated with photo-allergic reactions (an allergic reaction triggered when the sun reacts with the oxybenzone on the skin), and has been linked with estrogen effects in animal studies such as binding to cellular estrogen receptors and larger uterine weights. Several other compounds in sunscreens are also thought to have hormone-like effects.  Vitamin A derivatives in sunscreens have been associated with cancer.

Some sunscreens that are considered safer than chemical based formulations use inorganics or minerals like zinc and titanium to absorb UV rays. Recent technology has allowed the old greasy white zinc ointments to be replaced with colorless sunscreens containing zinc and titanium nanoparticles. Potential health effects of these nanoparticles are unknown.  Although they are not well absorbed through the skin, they may be inhaled when they are applied as a spray.

The Environmental Working Group has just published their annual on-line guide to sunscreens which reviews safety information on numerous chemical components of lotions and sprays. It recommends avoiding sunscreens containing oxybenzone and Vitamin A derivatives (retinols) and advises sunscreens that use inorganic, nanoparticles of zinc or titanium, and lotions rather than sprays.

Instead of applying sunscreen, consider using protective clothing instead. Shirts and bathing suits that provide UV protection are available for both children and adults. They are light weight, comfortable, and provide protection even when wet. Hats should have a 2-3 inch brim all the way around to protect the face, nose and ears. A “shade cap” has added  fabric at the back of the hat to protect the neck.  Loosely woven and mesh hats may not protect as well.  Sunglasses should fit well.  They should be labeled to block 99-100% of UVA and UVB radiation and they should be large enough to cover and wrap around the eyes.  Children should wear smaller versions of sunglasses with the same protection, not “toy” sunglasses.

First and foremost, avoid sunburns! The sun’s radiation is a known carcinogen so minimizing sun exposure is the most important step to preventing skin cancer.

When in the sun use protective clothing as the first line of defense against sun exposure, especially for children and pregnant women who may be more susceptible to the health effects sunscreens.

Avoid the use of sunscreens containing oxybenzone and retinol. Look for products containing zinc or titanium.

Avoid spraying zinc and titanium sunscreens on the face and upper chest so that inhalation will be at a minimum. They can be sprayed into the palm and then applied.

More Information:
Environmental Working Group’s Sunscreen Guide 2011

American Cancer Society – Skin Cancer Prevention and Early Detection

Environmental Protection Agency – Sunwise Program
Int J Androl. 2008 Apr;31(2):144-51. Epub 2008 Jan 10.
Developmental toxicity of UV filters and environmental exposure: a review.
Schlumpf M, Durrer S, Faass O, Ehnes C, Fuetsch M, Gaille C, Henseler M, Hofkamp L, Maerkel K, Reolon S, Timms B, Tresguerres JA, Lichtensteiger W.

Acknowledgements to Dr. Virginia Evans, Occupational Medicine resident at the University of Illinois at Chicago, for her work on this post.


One thought on “Here Comes the Sun

  1. Very informative post Dr Buchanan! It’s 98 degrees in Texas today & I’m going shopping for sunscreen with zinc &/or titanium!

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s