Monday, July 6, 2009

If the sun cancer doesn't kill you the sunscreen will (AKA The back from the beach blog)

Before heading down to florida for the July 4th weekend at the beach, I prepared. My skin tone is somewhere between my mother's olive skin and my father's pale-as-a-ghost untannable skin. Unfortunately, it is not an even split and I lean far closer to my dad than my mom.

That being said, I can tan, but I can burn even easier, so to keep my youthful appearance I make sure to have plenty of sunscreen. Or is that sunblock? Think there isn't a difference? Can you navigate the UVA/UVB alphabet soup? After reading articles similar to the this I got educated about the difference.

QUICK SUMMARY:
UVA causes cancer and aging, UVB causes sunburn. Sunscreen absorbs, Sunblock reflects. Did you know that SPF (sun protection factor) numbers are only for UVB? There is no scale for UVA. The definition of SPF is the length of time a product protects against skin reddening from UVB. 15 SPF protects 15 times longer - about 5 hours, 93% protection. SPF 30 =30 times longer, blocks 96.7% of UVB. The improvement is minimal at higher SPFs: 50 = 98% blockage and 100 is 99%.

Just because a sunscreen blocks both UVA and UVB does not mean it blocks ALL UVA frequencies. To be sure you block all cancer causing rays, you need these three ingredients: Avobenzone, Zinc or Titanium. And you need approximately 10% of one of these materials to get full blockage. Plus, you need to reapply every 2 hours, or the effects of sweating will diminish the effectiveness.

I've read a number of websites that are concerned about the stability of Avobenzone (also seen on labels as Parsol 1789 or butyl methoxydibenzoylmethane), but a number of studies declare it stable-that is, if by itself. Avobenzone degrades nearly completely if used in combination with Zinc or Titanium. In the U.S. you can't combine these ingredients, but so many people use makeup with mineral sunblocks, you can unintentionally negate the effect of your Avobenzone sunblock. So be careful with layering of sunblocks. More is not always better.

Okay, back to my story. After stocking up on my UVA/UVB sunblocks: Aveeno for the face (has Avobenzone) and Neutrogena fresh cooling mist (I love the cooling in the heat!) [has Avobenzone], I headed to the beach. I thought I was prepared. Until I read this by the Environmental Work Group (EWG).

I looked up the Neutrogena first, since I use it on most of my body. And I noticed in the top right it had a toxicity rating of 6/10. Curious, I paged down, and found one of the active ingredients was a 9/10 toxic rating! And when I did more research on this page I discovered that two ingredients in MOST sunblocks (including mine) are highly toxic especially if absorbed into the skin - and they are highly absorbed - Octinoxate and Oxybenzone. These two sunscreens can cause allergic reactions, lead to hormone-driven uterine damage, and can act like estrogen in the body.

But looking on the Neutrogena page, and clicking on Oxybenzone reveals it does much more damage: neurotoxicity, endocrine disruptions, and hematologic and renal abnormalities. Of course, all my lip balms with SPF have one or both of these toxic compounds. I'm sure none of that ends up in my mouth and gets into my system.

While zinc and titanium are potentially carcinogenic and disruptive to bodily functions, they are do not seem to be absorbed through the skin, even if in the nano form. So I'm less worried about those. Avobenzone has low absorption also, and its toxicity seems to be less defined as with the other common toxic ingredients.

By the time I read all this, it was too late. I have enough sunblock to last for a year. But I do have several lip balms, and I will use the non-protective but also non-toxic ones since I use them for dryness primarily. In the future, I will buy sunblocks listed as approved on the EWG web page and feel (somewhat) confident that I will protect myself from skin cancer and also not toxify my body.

UPDATE

After posting this blog I had a reader suggest another chemical that seems superior in its UVA coverage that is approved for use in U.S. but is not in wide use: Mexoryl. A nice review of it is here - best UVA coverage, doesn't break down, negligible absorption, water soluble so if absorbed (e.g. swallowed) leaves the body quickly, low toxicity, but misses some of the UVB spectrum (that causes sunburn).

Likely Mexoryl (SX) will need to be packaged with another component to get more UVB protection, but it seems like a great ingredient to prevent cancer and aging with low toxicity. There is a version of Mexoryl (XL) that is not approved in U.S. yet, but available in Canada that has FULL UVA and UVB protection. The article I linked to has a link for where to buy sunscreens with Mexoryl - Loreal makes a bunch. For Mexoryl XL do a froogle search-there are many in canada (Ombrelle was recommended to me) [though I don't recommended anything not approved by F.D.A. You buy anything like this at your own risk...]

2 comments :

  1. Cynthia StephensonJuly 9, 2009 at 9:01 AM

    Great article! I learned a lot about suncreens that I did not know. Thanks Ilene, I can now give better advice to my patients.

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  2. I'm shocked that you, as a doctor, would rely so heavily on the reports of the EWG. They are a notoriously dubious resource, known for misinterpreting studies, using fear-mongering tactics to push their agenda, even overtly skewing the facts (check out this entry on the dangers of polyparaben, complete with numerous citations. Nevermind the fact that polyparaben DOESN'T EXIST, EWG has been alerted to this mistake numerous times, and yet chooses to leave the entry up).

    For those that want real research to back their science, I suggest checking out PubMed.Gov- the online archives of the US National Library of Medicine.

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