How to protect yourself from sunburn (but still get some Vitamin D!)
Recently my daughter came home from day camp with a horrible sunburn on her back, where she and her teachers had forgotten to apply sunscreen. She is, like me, fair skinned, burns and freckles easily, and doesn't tan much at all. I have to harangue her to remember to apply sunscreen, but is there a cost? Is there toxicity, or, will sunscreen block her vitamin D production? I decided to look into this question a little more deeply. What is the best way to enjoy the summer weather, care for your skin, and get enough vitamin D at the same time? There are a number of controversies about the use of sunscreen: do sunscreens actually cause skin cancer or prevent it? Can you get enough vitamin D while wearing sunscreen? Are there toxic ingredients in sunscreens that should be avoided at all costs?
First, to understand some of these controversies, let's review exactly how sunscreens work. There are two main types of sunscreen: physical (or mineral) and chemical. Physical sunscreens contain reflective minerals like zinc oxide and titanium dioxide. These sit on top of your skin and reflect the UVA and UVB rays that are damaging to the skin (simply put, UVB rays cause sun burns, UVA rays cause skin aging). These sunscreens work immediately upon application to the skin and tend not to clog pores or sting the eyes. They offer broad spectrum protection. However, they often give a white tint to the skin and must be applied generously so UV rays don't slip between the molecules.
Chemical sunscreens work quite differently. They contain organic (carbon-based) compounds, such as oxybenzone, octinoxate, octisalate and avobenzone, which create a chemical reaction and work by changing UV rays into heat, then releasing that heat from the skin. They take about 20 minutes to take effect. They are invisible once applied so have a good cosmetic effect. For some people, these sunscreens can cause skin irritation and sting the eyes.
But do they work to protect you from skin cancer? Some people believe that they do, and others believe that they only protect from sun burn, thus actually increasing skin cancer risk. In the past, there was some mixed data on this. However, there was a 2010 study from Australia in which 1600 people either applied sunscreen daily for 4 years, or occasionally for 4 years. After 10 years the daily appliers had a 50% reduction in melanoma. Given the size and length of this particular study I feel comfortable saying that yes, good sunscreens can reduce the risk of melanoma, the most dangerous form of skin cancer.
So what about those chemicals? There is controversy about many of the ingredients used in chemical sunscreens. Oxybenzone, in particular, is a possible endocrine disrupter, based on some animal studies. Those studies used much higher doses than we would normally be exposed to with normal sunscreen use but this is still of concern. There is concern about other chemical sunscreen products being potentially carcinogenic as well.
And what about Vitamin D? You would think that sunscreen use would prevent the formation of vitamin D in the skin, but there are some studies that refute this. It doesn't take much sun exposure to crank up Vitamin D production so putting on sunscreen and then getting out in the sun actually raises your vitamin D levels, at least in one study. Another double-blinded study showed that sunscreen appliers had the same increase in vitamin D levels than people who applied a placebo cream. It seems that getting some sun, whether or not you're wearing sunscreen, will increase your vitamin D levels.
The bottom line: in my opinion, the physical sunscreens are superior to the chemical sunscreens, both in ability to protect from harmful rays, and because zinc oxide and titanium dioxide are relatively non-toxic, and are not absorbed into the bloodstream in significant amounts. Although they are a little white-ish on the skin there are some formulations that either blend in really well or are tinted to look more like makeup or just to blend in better.
A great source for checking the toxicity of the skin products you use is the Environmental Working Group's Skin Deep website: http://www.ewg.org/skindeep/.
I like that they rate the safety of products and explain which ingredients are better than others. Some sunscreen brands with a "1" (best) rating are True Naturals, Blue Lizard and Goddess Garden. You can also shop the skin care section of my Fullscript store for some good sunscreens that meet the EWG's criteria. Shop here!