Blog

5

3

Study: Many Sunscreens May Be Accelerating Cancer

WASHINGTON (May 24, 2010) -- Almost half of the 500 most popular sunscreen products may actually increase the speed at which malignant cells develop and spread skin cancer because they contain vitamin A or its derivatives, according to an evaluation of those products released today. AOL News also has learned through documents and interviews that the Food and Drug Administration has known of the potential danger for as long as a decade without alerting the public, which the FDA denies.

http://www.aolnews.com/2010/05/24/study-many-sunscreens-may-be-accelerating-cancer/

Note that this story is from a year ago and the FDA did the study over 10 years ago and are just last year telling us about Vit A in sunscreens.

For those of us that are/were sun worshippers, have you ever heard of the connection between topical Vit A in sunscreen and the incidence of skin cancer?

For Vit D3 health reasons we know that exposure half naked for 20 min...10 min on a side is an excellent source of Vit D3...without sunscreen.

Avoid sunscreen and avoid skin burning and you avoid skin cancer.

flag
That's exactly how I roll. Think I'll go outside right now. – Forrest May 6 2011 at 22:09

9 Answers

29

Hey, I get to give another "chemist's view" on this! Quick disclamer: I'm only talking about mechanisms here and trying to extrapolate to the effects on humans. Just like in my last "chemist's view" on AGEs, I'm making no representation about our evolutionary adaptations to handle things. I'm just talking about the underlying chemistry.

I'll start at the beginning: Light that we see comes in many different "colors", we call them "red", "blue", "green", etc. Ultraviolet light also comes in may different "colors", the terms physicists use are "UVA", "UVB", "XUV", "VUV" (the atmosphere absorbs all of the XUV and VUV, so we don't encounter that in the real world). Not all sunscreen absorbs all colors of UV. They generally absorb the colors of UV that cause tanning and burning (because that's the observable that people care about), but they don't generally block the higher energy UV colors that actually cause the cancer. Because the effect of that isn't marketable, no one would know it's happening.

Without sunscreen, your skin "sees" some UV colors and starts to "tan". The tanning is your body's natural protection against the higher energy UV colors that cause the cancer. So as long as you're not out long enough to get burnt (actual skin damage), the tan protects you against the bad stuff.

So strike 1 against sunscreen: it stops the good stuff that promotes tanning and lets through the bad stuff that causes cancer (that our tan would protected us against if it was allowed to form).

Strike 2 against sunscreen: The UV that causes us to tan is the same color of UV that is used in the formation of Vit D which also protects against cancer.

Now, lets say that there was a magical sunscreen that blocked 100% of all colors of UV, would I feel comfortable using it? No. Here's why:

Sunscreen works by "absorbing" UV rays. How does it work. Well it's generally a long polycyclic aromatic with lots of conjugated double bonds. The UV light is resonate with the electronic transitions of the conjugated states. When the UV light hits the sunscreen molecule, it promotes an electron into a higher state which actually breaks one of the double bonds. Most of the time the sunscreen molecule will then shed that extra energy it just absorbed as heat and reconnect that double bond. But sometimes it won't and you'll be left with a free radical (just like you're probably aware - since you're reading paleohacks - PUFAs are susceptible to oxidative damage - just image a sunscreen molecule as a more reactive PUFA). So when you started, you put a reasonably harmless chemical on your skin (or else the FDA wouldn't allow it to be sold), but it's interaction with light turns it into a potential carcinogen just like PUFAs and PAHs.

Strike 3 against sunscreen: The act of doing it's job (absorbing UV) turns it into a potential carcinogen which is now slathered over your largest organ.

Personally, ever since I worked through these mechanisms, I've never used sunscreen again.

That enough chemist rant for now. I'm happy to add to it, just don't want to bore you to death just yet.

link|flag
no that was awesomely informative! thanks – tartare May 6 2011 at 22:53
Awesome and informative. Thank you – Todd May 6 2011 at 23:32
1 
 Mike D rocks like a Beastie Boy! – baconbitch May 6 2011 at 23:50
1 
 Awesome explanation. But now, I'm tormented. I am a strawberry blonde, blue eyed white girl with freckles. And I'm an adventure guide. This summer I'll spend all day, 6 days a week in bright sunlight, on a reflective surface, water. Other than wear long sleeves and a big hat, how do I keep my face and hands from burning? It takes months (and usually a burn) in order for me to tan – WayfinderAli May 24 2011 at 0:38
Great answer. You should see this post by Michael Eades: proteinpower.com/drmike/supplements/… The part that is quite similar to what you said is towards the end: about the distinction between UVA and UVB and the dangers of a sunscreen that would only block the good one and let through the bad one. Eades's next step, however, is to doubt that the new sunscreens marketed as blocking both UVA and UVB are actually doing that job properly. Your next step is a little different but just as interesting. – Paul Jun 2 2011 at 21:07
2

I agree that most sunscreens are detrimental to health. I do believe that there are a nice assortment of sun blocks that are protective without doing harm. EWG agrees with me on this. I use an organic (zinc only) sunblock every single day. I do try to expose my limbs to sun for 15-20 minutes a day for D but no more than that. My face, neck, ears and chest are always covered with block. Unfortunately I've seen a number of people eaten up with cancer of the head and neck and it is beyond frightening. A good friend of mine just yesterday had a huge crater the size of a tennis ball cut out of her leg because at 40 she was diagnosed with skin cancer. It would take a whole lot more scientific evidence that a well-formulated sun block does more harm than good to get me to change my sun block habit.

link|flag
what is the difference between a sunscreen and a sunblock? – tartare May 6 2011 at 23:10
Both terms are equal. I presume for marketing purposes...a screen implies some penetration...a sunblock, no penetration. – Dexter May 7 2011 at 0:46
thats what i was thinking... – tartare May 7 2011 at 2:51
2 
 No they are different. Sun block is a product that has active ingredients that reflect light The active ingredients in these are inorganic/ mineral (Titanium dioxide and zinc oxide). A sunscreen uses chemical or chemical/mineral combo actives that absorbs the energy of the sun. Very different things. – Shari Bambino May 7 2011 at 3:08
1 
 Check out EWG's list of approved sunblocks and suncreens. I think Blue Lizard is good and readily available in drugstores. Burnout is something you have to order online but it's excellent. I currently use Marie Veronique tinted on my face and love it. I also like the Vanicream products but you have to order that online as well. ewg.org/2010sunscreen/best-beach-sport-sunscreens – Shari Bambino May 7 2011 at 3:20
1

And to think I use to wear sunscreen religiously for 5 years because I was afraid of wrinkles, makes me want to go back in time and punch myself in the face repeatedly.

link|flag
1

So what do you do if you are at the beach all day, or out in the sun all day? I don't know about you guys, but I'm def not gonna wear long sleeves, and pants when I spend the day in the sun. So how do we protect ourselves from hours of continuous sun exposure?

link|flag
1 
 Your body does it for you. That's what getting tan is for. Going out for 4 hours and getting burned in the blazing sun is analogous to taking a 15 foot drop after 2 weeks of parkour training and then complaining about your joint problems and looking for a modern product to solve it. Also long sleeves aren't hot at all if they're white and loose fitting. In fact they're COOLER! Modern society is just so silly... – Anonymous Coward May 7 2011 at 2:09
1

I started using Extra Virgin Coconut Oil (yes, the kind you cook with) before I go out in the sun. No more sunburn, just a nice golden tan! It also is a great moisturizer, makes your skin feel nice and silky. I live near the beach and am out in the sun ALOT during the summer months. I found on quite a few 'paleo' sites and blogs the use of Coconut Oil for tanning. Sounded crazy, but I thought I'd give it a try. Of course, I wouldn't try going out in the sun for 4 hours the first time, but I usually am out in the sun for 90 min. to 2 hours a day several times a week, and the coconut oil works great!

link|flag
I was watching a survival show once and the guy cracked open coconuts and spread it all over his body. He said it's a natural sun blocker. – GPS May 14 2011 at 11:46
Yup. . .pretty amazing :) I guess you could consider it a 'paleo' sunscreen – Lucinda May 16 2011 at 12:48
I do this too- I'm pretty fair and it works! – Jules K Jun 24 2011 at 14:53
0

those Jerks at the FDA have done it again! 10 years? Well, fortunately i ignored them on that one too, along with butter, fat and salt. Wish I could say the same for my Irish in laws.

link|flag
1 
 Well, too much salt is no me gusta. However, I will agree with you on the FDA b.s. I look very carefully at who funds a lot of these studies that tell us to buy products or we'll die. Remember - 4 out of 5 docs recommended Lucky Strikes :) – baconbitch May 6 2011 at 23:52
0

I never use sunscreen, and I spend a lot of time outside in the sun. I simply try not to burn. That's all I feel is necessary to stay healthy. We'll see I guess!

link|flag
That's what I have done my whole life. If I'm at the beach and don't want sun I put a tshirt and hat on. I like being tan...makes you look and feel ten times better. – GPS May 14 2011 at 11:42
0

For discussion purposes, I brought this up to my dermatologist a few months back. She instantly shunned the concept, saying that the depletion of the o-zone layer etc, has lead to far stronger rays than we would have experienced, and I'd basically be asking for cancer if I didn't wear SPF 50+ anytime I was out in the sun for more than 30 min. Unfortunately, I was getting a pre-cancer frozen off my lip at the time so I didn't have much of a leg to stand on.

For better or worse, I still don't wear the stuff. The idea of it doesn't make sense to me at all.

link|flag
She may be right about the 30 min. We do not want to burn our skin...only absorb the UVB to make Vit D3 for 30 min...then no more. I personally think my ketogenic diet also protects me...but I have no proof. – Dexter May 7 2011 at 1:54
Context does come into play, though. If you have a solid tan and can be out for a couple hours without getting pink, I'd say you're fine. I could be wrong. But what I've taken from all this, is that if I know I'm gonna be in the sun for enough time to burn, I'll cover up with clothes rather than use SPF. Seems like a safe compromise. – Todd May 7 2011 at 3:18
And I think toxin minimization (through clean eating) helps. – Todd May 7 2011 at 3:19
0

What do you think happens when you bake aluminum into your skin? The best sunscreens are clothes, shade, and for purposes of "paleo re-enactment"....mud!

link|flag

Your Answer

Not the answer you're looking for? Browse other questions tagged or ask your own question.