Dear Science

Comments

1
Would it be socialism to outlaw chemical sunscreens that cause cancer?

I understand that as a US Citizen it's my job to protect the profits of private corporations, but I'd rather not get cancer. Do I have to get cancer to be a real American?

It's not government's job to regulate industry, right, because that's big government, and so I can understand why chemical sunscreens have the right to ask for my money in exchange for cancer.

So you shouldn't tell people that things give them cancer. You have a responsibility to the makers of cancer causing sun screen, and if you worked for the government, and did that, then that would be socialism. Right?
2
Oh Joy! I was just diagnosed with Melanoma, likely caused by frequent childhood sunburns back in the early '60s. I just filled my house with cans of clear sunscreen at every door. It is probably like closing the barn door after the horse has left, but after the Dr. hacks a huge chunk of your skin out, you really don't like the sun too much. I wonder if they make a male berka....
3
The reason many newer sunscreens go on "clear" is a result of nanotechnology -- when the titanium dioxide particles are small enough, they become clear, rather than the white that we are used to. (Virtually any material that is "white" uses titanium dioxide for color, and even many that are not white use it as a base color.)
4
Reasons for me to use the "white paste" sunscreens: I'm sensitive to chemical sunscreens, and they make me feel like I already have a sunburn. And no matter how non-greasy or oil free they promise they are, wearing them still makes me feel like I've been dipped in a vat of vegetable oil.

Of course, finding a non-greasy zinc or titanium sunblock isn't easy either. I have to order them on the internet instead of just going to the local drugstore. It's easier to just stay out of the sun altogether when I can. On the one hand, I look about 10 years younger than I actually am, which is nice, on the other I'm too embarrassed to wear shorts in public because my legs just about give off their own light.
5
Uhhhm, no. Your last paragraph is incorrect. Free radicals coming from the components in the sunscreen (generated by sunlight) are not going to transport through your dermal cell walls. Now, free radicals created inside the cell (because you're not using sunscreen) could cause DNA damage...resulting in melanoma.
6
Another disturbingly unreferenced article. Another simmering controversy in medicine that this physician has never heard of. And a great mystery: how do those free radicals, subatomic particles, make their way unperturbed through layers and layers of dead skin cells full of keratin and whatnot, down to living cells and beyond them to the cells that regenerate to replace the upwardly migrating skin cells, you know, the ones that accumulate DNA damage over the years and eventually cause precancerous and cancerous lesions (not just melanomas)?
7
Here is the reference: Hanson, Gratton, and Bardeen; Free Radical Biol. and Med., 2006. Sunscreen enhancement of UV-induced reactive oxygen species in the skin. (or Google "sunscreen and free radicals" for reviews of the paper because it has private content)

The study was done on a skin cell line. The issue is that NOBODY KNOWS if the free radicals can penetrate cell layers in actual human skin or not because NOBODY HAS LOOKED YET. That's why it's a controversy. Also, there is evidence to suggest that more things that we put on our skin absorbs into the underlying tissues and capillaries than we ever thought before (see EWG website for a start) because certain synthetic chemicals that are only in skin-applied cosmetics/lotions (i.e. not in food) appear in people's blood and urine. Remember that just because you learned some stuff about the epidermis from one class in med school 20-something years ago -- from a teacher whose knowledge was itself 20 years out of date -- does not mean that you are up-to-date with modern scientific knowledge. Also "I can't think how it would happen" is not an acceptable substitution for "I've looked and it doesn't happen," thanks.

More research needed, please, on which substances can penetrate skin and under which conditions. And then it will trickle down to physicians over the next 40 years.