Science & Health Channel theme day … Sun!
Another month and another theme day for SciHealth. Our theme is Sun. June, summer, fun, sun. Ouch! Sunburns!
Although it’s pouring rain here right now (not much of a chance of a sunburn today), I thought I’d explain how sunblock works.
I found a decent explanation at the Library of Congress and it’s pretty simple. Sunblock contains things that deflect or prevent absorption of UV A (the ones that make vitamin D) and UV B (the burning rays) by our skin. Commonly zinc oxide is one of the main ingredients. Now, there is some question about the over use of sunscreen and that people aren’t getting enough of the good UV rays. Well, while this might be true, a little unprotected sun exposure is good for you, it’s really hard to judge how much is too much (ouch).
Generally, now that summer is here, just slather it on. And drink some milk.
Tags: sunscreen
8 Comments
ummm this may be a really dumb question, but why milk?
Vit. D.
Last night on CNN I saw a story about how most sunblock blocks UVA or UVB (I don’t remember which now) but not the other, at least not very well. And then some monthly test of the emergency thing came on and it blocked out the sound of the story, so I have no idea what else they said or what they suggested people do about it. It was really frustrating. Have you heard anything about this?
I have Trisha. To protect against burning it has to block UV B. I’d say Consumer Reports would be the best place to look for that kind of information. I think there have been calls to allow more UV A in because there are some anti-cancer and other good effects from a little exposure to UV A.
So this means moderated exposure to the sun can be both helpful and harmful at the same time?
Incidentally, does skin pigmentation, i.e. darker or fairer, really have weight on the posibility of a person to get skin cancer?
That’s right Sasha. A little sun is good for you, there is a reason we’re adapted to turn UV in to vit. D. As for dark skin and skin cancer, that’s hard. Light skinned/fair skinned people do tend to burn more easliy, so they are more at risk. But that’s about all I know.
You still need some Vitamin D produced by UV radiation, dietary Vitamin D alone isn’t sufficient.
Basically if you go for a 10 or 15 minute walk outside you’d get enough Vitamin D produced and you’d be pretty unfortunate to get sun cancer from that kind of exposre.
I just saw a new story today about UVA/UVB protection from sunblock at NPR: http://www.npr.org/templates/story/story.php?storyId=5509976
Apparently some sunscreen makers are being sued now for claiming their products do more than they actually do. One of the issues is that the UVA protection is much weaker but it is UVA that contributes to skin cancer.
Interesting stuff – and I have to admit I was one of the people who trusted what those labels say!