This holiday weekend many of us will be heading out to the beach, lakes, mountains, or just gardening in the yard. The forecast here is for lots of sun, so lots of sunburns on that winter white skin.
So many will grab the tube of sunscreen out of the medicine chest, slather it on, and think they are safe. It could be our obsession with sunscreen which has given way to the rise in skin cancer in the past decades. Lets back up for a bit of physics and biology.
The sun’s rays consist of visible light, inferred, which we feel as heat, and Ultraviolet, which we can’t see, but these very short wavelengths can penetrate out skin. The two ranges we often hear about are UV-A and UV-B.
UV-B is the shorter of the two and is the one responsible for the sunburn we are all probably too familiar with. UV-B is also the wavelength which converts cholesterol in our skin into Vitamin D. Most of the sunscreens were designed to block the UV-B rays to help prevent a burn (Remember UV-B like Burn)
UV-A is the longer wavelength, which can penetrate deeper into the skin, and play a major role in skin aging and wrinkling. UV-A also can cause mutations and DNA damage in the basal layers of the skin where most skin cancers begin.
Lets talk a bit about Vitamin D. There is an avalanche of research coming out on Vitamin D over the past years and it is a key ingredient in your bodies anti-cancer defenses. Vitamin D is fat soluble and is produced by a reaction in your skin brought on by exposure to UV-B rays. Once vitamin D is produced it resides in the surface oils in your skin and takes 18 hours or more to be absorbed deeper into the skin where it can become available to the rest of your body.
So lets take a look at a couple of scenarios:
- The common scenario for the past few decades: You go out in the sun, slather on a traditional sunscreen so you don’t get a sunburn. If you were good you reapplied it ever few hours. Keep reapplying and you could stay out in the sun all day without burning. So what was the end result? You didn’t burn, you didn’t produce much vitamin D, AND UV-A rays did lots of damage to your deeper cells and may have pushed you one notch closer to starting the cascade of events which lead to skin cancer. Vitamin D could help prevent this, but you didn’t produce much because you kept the sun screen on which blocked the UV-B rays.
- The other common scenario is that you didn’t put much sunscreen on, or maybe none at all, you were in the sun for a little while, started burning, and covered up or went inside (or maybe stayed out a bit longer and fried yourself. so in this scenario, you produced a ton of vitamin D. You didn’t do near as much damage to your deeper skin from less exposure to UV-A. Then you went in and very gently took a shower to get the salt water, lake water, sweat or what ever else off. Well doing that just washed all that vitamin D down the drain. So you’ve done less damage than the first scenario, but still lacking vitamin D.
- A better scenario: you slather on a full spectrum sunscreen which has agents to block both UV-A and UV-B rays. So you don’t produce the vitamin D, but you don’t burn nor damage your skin long term.
- Well there is one common scenario: Go out have fun hiking, biking, in the boat, etc. Get some good sun, maybe a little pink, but hey, you’re out camping, so you don’t take a shower until you get home, so that vitamin D has a chanced to get into your system and offer some anti cancer protection.
- The final scenario, which is what I try to do, is I take 5,800 iu of vitamin D per day in supplements spread out twice a day. Then I use a full spectrum sunscreen as much as I can. I try to keep a shirt on my pasty white body which hasn’t seen the sun all winter.
There are numerous chemical names for each compound, so you may see something else listed on the label. For example Ethylhexyl Methoxycinnamate is also known as Oxybenzone. Ethylhexyl Methoxycinnamate and Octyl Methoxycinnamate are also known as Octinoxate. So it may take some research to see which chemicals are the sunscreen agents. A good source for honest scientific skin care ingredient information is http://www.cosmeticsinfo.org
|Active Ingredient/UV Filter Name||Range Covered|
|UVA1: 340-400 nm|
|UVA2: 320-340 nm|
|UVB: 290-320 nm|
|Aminobenzoic acid (PABA)||UVB|
|Ecamsule (Mexoryl SX)||UVA2|
|Ensulizole (Phenylbenzimiazole Sulfonic Acid)||UVB|
|Meradimate (Menthyl Anthranilate)||UVA2|
|Octinoxate (Octyl Methoxycinnamate)||UVB|
|Octisalate ( Octyl Salicylate)||UVB|
|Titanium Dioxide||UVB, UVA2|
|Zinc Oxide||UVB,UVA2, UVA1|