Wednesday, August 5, 2009

SunScreen Will Kill You - and other single factor melanomas about being in the sun

This post is perhaps a kind of meta-review of sunscreen - to use or not to use, and if not, why not. I was horrified at a recent course in a very sunny very hot location to hear that sun screen causes cancer. Especially after hitting the SPF 70 pretty hard all week. Doesn't this go against everything we know to be true and holy about protecting us from the sad 20thC induced evils of the sun?

A doctor at the course argued that we are supposed to get those sun's rays, not be blocked from receiving them. Yes, but my grade 8 science fair project reminds me, that was before we destroyed the OZONE LAYER. Ok ok, ozone does mostly UV-B filtration, which is sun burn world, and it's UVA that causes apparently the real mess that can lead to melanoma in particular. Thanks for the non-help, ozone layer. And yes there are indeed reports of badder types of skin cancers happening with reduced ozone protection. So don't we need that magic chemical sealant to let us not fear the suns less mediated rays?

And what's behind this assertion of evil sun screen? Is it the sunscreen itself that is toxic, supposedly? i mean a lot of them do have titanium dioxide in them - that's metal. Are we making ourselves into carcinogenic tin men?

2004 - the year it all started to change in the Solar System
Ok, if we go back a few years, here's what's been said (as 2004/2005 seem to have been the highpoints in the public discourse around sun screen/no sun screen):

1) Complaint 1. We need the sun to generate vitamin D; if we put on sunscreen we're stopping this critical process from happening.
Hmm. Try living on the West Coast of canada. Or anywhere in the UK. You could walk around buck naked all winter and still be vitamin D deficient. In fact we are. Which is one of the main reasons we're told we need to supplement our vit d intake EXCEPT during those periods of the year where we can get 15 mins of full body solar exposure.

Ok, i was out for 20 mins for lunch in the one sunny day in seatle a month ago. No sunscreen, forgot the long sleeve shirt. My arms burned. I don't think burning is good for the immune system either, do you? No it's not.

So what do people of dark, damp northern climes do? Take Vitamin D. Good quality vitamin D (it pays to check). But it works. Here's one example of a study that says vit D and calcium supplementation reduces risk of cancer.

BUT does the assertion hold that sunscreen actually stops vitamin D photosynthesis? Er, no, not really. Sunscreens do not block all UV radiation (though i dunno, that 70SPF i tried recently seemed to keep any evidence of sun exposure well hidden, but anyway). Then the question is suppose you're out in the sun, well lathered up in SPF, is the radiation hitting the skin sufficient to trigger Vit D synthesis?

Well, a dermatologist in 2005 thinks all's wellciting a 1997 study in 2005 :

dermatologist Darrell S. Rigel, M.D., clinical professor, New York University Medical Center in New York City, did exactly that. Rigel’s message: sunscreens do NOT block all of the UV radiation hitting the skin, so that those wearing sunscreen are still able form vitamin D.
Now, there's been a ton of research into Vitamin D since 1997, and much of it has shown that there is such a thing as a vit d deficiency and supplementation is necessary cuz we're not out in the sun (when there is any) enough to get what we need. Riggel, sticking with 97 research, thinks we get just enough from daily activities and "diet" without supplementing.

maybe he's right but he's increasingly alone in that conviction in the research community. It's interesting to me that it's dermatology associations that are making claims about getting enough vit d, when they're also the ones promoting sun screen. Anyone else? Yes there is. Well there's one. A piece from 2006, histrionically titled "darkness at noon" suggests that sunscreen does block vit d formation.
In fact with sunscreen applied only miniscule amounts of preD3 are predicted to be made outdoors even with extensive exposure.
Here's what this means:
  • typically high noon sun is the best for vit d production (also, they acknolwedge, the best time for sun burn risk).
  • With SPF 15 on, according to these researchers, it would take 4-6 hours of that KIND of sun to get enough to get the right vit d levels. And, as they point out, that kind of sun just don't last that long - even if someone were out in it.
Their recommendation?
We observe that brief unprotected midday exposure is optimal for promoting healthy vitamin D status while simultaneously minimizing accumulation of sunlight related risk. We further find that SPF-15 sunscreen, regardless of exposure scenario, reduces preD3 effective UV to levels well below that considered to provide practical vitamin D benefit, dubbed "vitamin D winter." Wearing high SPF sunscreen, essentially turning off the lights on vitamin D, is like darkness at noon.
SO 20 minutes of mid-day sun, assuming pretty much full body exposure (10mins front; 10 back, not kidding), is good for vit d generation. Well again, in the winter (and we might talk about seasonal effective disorder) this isn't usually possible. And in dark climates, this isn't usually possible. No wonder so much work has been done in Australia.

We'll come back to going au natural in the sun in a moment. But first, the second claim about sun screen.

2) Complaint 2: Sun screen has toxic chemicals. Artificial fragrance and other stuff that are stabilizers in some sun screens can get absorbed into the skin and play havoc with our immune system.
Well hmm again. Anything pretty much we put on our skin can be absorbed by our skin.
As for sunscreen yes back in 2004, sun screen stuff was shown to do what stuff on skin does: get absorbed - to some degree. But it also gets spit out in urine too. So is this harmful? Heh guess what, we don't KNOW.

Chemicals Good to AVOID
One chemical we do know to be problematic is oxybenzone. Avoid any sunscreen that has it
. PABA was also found to be just bad, but it's illegal to have in anything, so just run screaming - really - if you see anything with that in it. There's a few others that *may* be problematic: Benzophenone (benzophenone-3), homosalate, and octy-methoxycinnamate (octinoxate); Parabens (butyl-, ethyl-, methyl-, and propyl-); Padimate-O and Parsol 1789 (2-ethylhexyl-4-dimethylaminobenzoic acid and avobenzone).

Aside: God knows what long term harm i have done to something by the amount of Muskol bug dope (active ingredient: DEET) i used for years working on summer digs along the the Red River. I know it melted the lettering off watch bands and other plastics. But after awhile, you know, i think it was sort of an aphrodisiac. costs and benefits.

Now some folks may not want to take the risk of whether this kinda stuff is damaging. Some folks may prefer to walk around outside in a bug hell covered in netting (and when tree planting in Ontario, that's exactly what you did: bug nets - but you also did bug dope because you just can't duct tape up everything. I'm not kidding. Black flies, i tell ya: all wings and teeth.)

As for sun screen effectiveness/safety, guess what an organization called The Environmental Working Group (EWG) makes of sun screen (2009)? The biggest problem is that most of them don't block the right UV rays: UVB has been the focus - and rightly so - but UVA is apparently the stuff that is an increasingly known concern.

There other finding: ironically, many products in sun screens break down in the sun! har! - no, not har. When some chemicals break down what they break down into is not good.

So, the EWG has a list of 95 sunscreens (out of 1642) it's methodology assessed as recommended - low hazard and effective. Check it out. The methodology behind the selection is pretty clear and solid. Here's a summary:

Our analyses show that products vary widely, both in their ability to protect from the sun's harmful UV radiation, and in the inherent safety of the ingredients themselves. FDA has set no mandatory standards for any of these factors, and manufacturers are free to make products that may not protect consumers from the sun and that may not be safe when slathered on the skin.
What's behind our sunscreen investigation:
  • 1,642 sunscreens
Customized rating for each product includes:
  • Sun hazard (effectiveness) ratings for UVA protection, UVB protection, and stability in sun
  • Health hazard (safety) ratings for all ingredients
Ingredients evaluated in these sunscreens:
  • 14 of 17 active ingredients approved in the U.S. (the ones found in products)
  • 2 active ingredients approved in other countries (listed as "inactive" ingredients in U.S. sunscreen)
  • 2,150 other ingredients (not sunscreen)
Data sources:
  • Nearly 60 definitive toxicity and regulatory databases from industry, government, and academic sources see all
  • Nearly 400 industry or peer-reviewed studies reviewed in preparing this sunscreen study see all
So what can we say from the above about sunscreen and cancer?
There is no direct link in any study that says generic sunscreen causes cancer. We do know that
  • a) a lot of sunscreens still do not filter for UVA and that's not good cuz that can mean overexposure to these rays
  • b) some sun screens have ingredients that either break down in the sun and definitely don't do their job
  • c) some sun screens have chemicals in them that seem pretty clearly to do no good to the body
  • d) new bit: implementation can be an issue: while nano-lotions (nano-zinc etc) may be great, because stuff seems NOT to be absorbed by them, nano-based sprays may not be so good - their may be absorption issues.

So what about going neked? Is a Tan a Good Thing? or Two Guys in a Boat

If you ever want to get a lot of press and be taken seriously, call yourself something important. Like the Council on Vitamin D. Or how about the Health Research Forum. A swishy logo that looks all medical helps too. Use the terms "we" and "us" a lot to make it look like there's more than 1 or 2 of you and have a "board of directors" - even if there's only two of you. or 1.

In 2004 a "report" was released from the Health Research Forum called Sunlight Robbery. Written by Oliver Gillie. Before we consider this, a quote from the HRF's about us page: " Health Research Forum will be run by an advisory board which at present consists of Oliver Gillie and Michael Crozier. HRF is presently recruiting more people to serve on the board. A constitution is in preparation."

The date on the page is still 2004. It's August 2009 as i write. So there's this two pony show putting out a report. Just by way of context. Let this be a lesson in marketing and press exposure. Because despite what seems like quite the cover, the report seems well done.

what does this oft cited in the UK press of the day say? Well coolly, it re-presents in one convenient package a lot of research that had been done till that date about sun exposure relative to latitude, and why sun exposure is important for vitamin D generation, and why saying exposure of hands and face as sufficient is just wrong.

Now i have not read all the studies referenced in this report first hand, so i don't know if their use in the article is a completely fair and accurate representation of that work, but of the stuff i do know that's been cited, it seems that's pretty durn good.

It then goes into a HUGE section on why vitamin D is important in the prevention of everything, er, under the sun. Let's just say "ok" and move on. Let's get to the biggie of WHY sun screen in the first place: burns and SKIN CANCER.
another sunny day in the UK

Risk of Skin Cancer and other Evils like Burns from non-mediated sun exposure
Well in the Sunlight Robbery report, the collection of resources seems to suggest that melanoma is pretty insiginficant relative to all types of skin cancer, and may explain why the uk's various policies on how to lather up in the sun mayn't be doing much to retard the progress of such cancers. Diet is also proposed as more of a factor in skin related issues like actinic keritosis (skin aging) than sun. Again i haven't looked at the primary studies on this, but i'd be willing to give that one the benefit of the doubt.

And so Tanning - in the Real Sun?
The lay perception that a good tan is a sign of good health has been severely criticised by those who promote sun avoidance. In fact, scientific evidence suggests that the lay perception is correct and the public has been ill-served by the sophistry involved in suggesting that a tan is unhealthy. The phrase “there is no such thing as a healthy tan” is no more than a clever slogan devised by propagandists to discourage people from seeking sun exposure. Controlled exposure to the sun is beneficial and a tan, which provides some protection against sunburn, will naturally be acquired in the course of such exposure. It is quite wrong to make people anxious about a tan when there is no sound basis for doing so.
So let us leave the report then and see why tans may be a pretty good skin protection. For which i am grateful if that's the case, because while i wore a ton of deet on those happy summer digs, none of us then wore any sun screen. We were keen instead to see who could get the most dark - before slipping into a 1m square by 3m deep shaft for the end of the summer.

First, let us note that tanning beds are not a safe way to tan or generate vitamin D. No. bad. pooey. Good explanation of why over here/ An overview of the research and related badness can be viewed in this 2008 report.

Fake Tans?
that's another whole ball of wax, and i ain't going there. But remember what happened to Bond's assistant at the start of GoldFinger - the one painted in gold? If you're curious, go to and just put in "tanning" as a search term - most of the latest research is about tanning beds and the icky effects of a lot of fake tanning spray products.

Tanning: it's an inflammation
UV radiation damages DNA. Our bodies don't like this. Tanning is an inflammatory response to UV radiation. One of the multiple things stirred up in the UV inflammation response soup are pigment containing organalles. Now for folks with fair skin who say they "don't tan; they just burn" - this is entirely true. There are a couple of triggers in the skin of fair people that don't kick of the tan effect as part of the response to the sun. If you're interested in the detail of these factors, A Healthy Tan? in Clinical Implications of Basic Research, March 2007, is very cool. There's also a 2009 article that's looking at mathematical models of how tanning works through various layers of skin to find out more what's going on in the cells. Important.

An inflammatory response to a stimulant is a Good Thing. Muscle growth has a big chunk of inflammatory response in it, after all. Adaptation causing growth: inflammation. Good Thing. So tanning is doing the same thing, no? Natural sun screen IF you have those bits in your biology that trigger them. Fair skinned folks have a harder row to hoe for sure.

Does this mean that a really deep dark wrinkly leather tan is a good thing? Well, it's not particularly attractive. And folks i've seen with such tans don't look healthy in a whole lot of other ways, so is it far to say the problem is with the sun tan?? But overdoing anything seems usually to lead to a bad end, does it not? What if a deep tan actually inhibited vitamin d production? Combine that with an elderly, overweight, sedantary person (think cruise ships) and it's one more factor to poor health.

So why do we use sun screen again?
What if i go back to that grade 8 science project and the ozone layer and that the amount of UVA/UVB radiation filtering through our atmosphere is more intense than it used to be. And now i have to say, So? Is that really a big deal? yes! More intense rays mean faster burn times. But the big concern is less the local and controllable phenomena of burns to the risk of skin cancer in particular melanoma.

Gillies sunlight robbery report suggests we're all in a lather about low risk/low likelihood types of skin cancer from the sun - especially in the UK and similar latitudes. And while burns are bad (there's lots of uncontrovertible science that the second and third degree whole body burns from any source are Bad THings), well, there's work to show that even lighter burns can have effects like a correlation with reduced multiple sclerosis.

But a 2005 study, discussed here, seems to suggest that exactly what triggers the inflammation responses of tanning may be exactly what triggers melanoma mutations, too.

Risk management?
Of course, simply reducing exposure to the sun by getting out of it, or covering up when in sunny climes is also a way to limit harmful rays. You may say well, sun screen will keep more of those rays out.

Maybe it's like solar contraception. Sun screen is one type of device to keep all the sun rays out but it's not 100% fool proof either. It just reduces the risk. In the case of the sun, though, what we seem to be learning is that abstinence has negative side effects too.

It's a Balance? I'm going to rationalize my short term use of sun screen when in Arizona working out outside for a week as Just Fine. I did not want to burn, and i did not want to pass out from increased heat exhaustion trying to run around in full body clothing while doing sprints and i did not have time/opportunity for slow gradual exposure/adaptation.

I go back to the one time i have burned this summer was 20 mins. Just 20 fricking mins with no sun screen sitting outside in Seattle having lunch. Burn! And that was not fun. It was not severe but it was not great either. Ok, there i could grabbed a shirt rather than lather up. True.

That said, the burn did "turn into" a bit of a tan. And i'm not unpleased. But maybe i should be?

Begin2Dig sun screen/sun tan take away: death to single factor thinking.
Sun screen, it seems, does not cause cancer. It does mitigate the effects of vitamin D production, and in a country as sun poor as the UK or areas as sun starved as the Pacific North West, perhaps we're all insane to see the sun, wish to run out in it and scury back to the bathroom to put on the sun screen before rushing out.

As with anything to do with our embodied selves, there is no one stop shop answer. There are risks to being in the sun; there are risks to using sun screen; there are risks to tans; there are risks to not being in the sun. Dam dam dam.

It may just be that running around a bit without any sun screen is a Very Good Thing to do - unless you do just burn in the sun - then alas gradual exposure is super important.
We do *seem* to know that just laying out in the sun for long periods fully exposed may have some issues - but we also know that sun exposure may only be one factor in those issues. Diet and movement are pretty big ones too.

The sun is not evil - in proportion.

If anything is evil, it's got to be single factor thinking that finds an easy panacea in saying "no tan is a healthy tan; always use sunscreen" or "sunscreen is evil; expose yourself to the sun."

Things to consider:
  • how long out in the sun?
  • what time of day?
  • how can exposure be graduated by clothing vs screening
  • how ensure sufficient vit d intake no matter the approach?

So after all this, i may just cautiously step out into another cloud filled UK day tomorrow - right at Noon! in shorts and a T, and stay there for 20 mins. If it's not raining. True, it's taking a risk with those UVA and UVB rays, but it's a risk i feel more certain, if done cautiously, i'm willing to take.

1 comment:

Ron Ipock said...

you could hedge your bets by applying the ancient wisdom of Native Americans: wear a long-sleeved shirt and a hat. A nice flannel shirt is SPF 100000000 and all that without any toxic treacle.


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