With all the bad press that ultraviolet light is getting (skin cancer, cataracts, etc.) can we say something good for sun tanning? Foe one think, sunlight causes the human body to synthesize Vitamin D-a deficiency of which causes rickets. Look at the pictures of people in the 9th century (the age of Victorian prudery)-those people were tubercular, pasty faced, and unhealthy. Plus, I remember reading the account of a French doctor (he was a volunteer doctor with Medecins san Frontiers), and served in Afghanistan. He treated the battle wounded, and stated that he never saw a case of infection, even in severely wounded men. Since soap and water are not valued commodities in Afghanistan, he reasoned that the reason germs don’t thrive there is the high UV flux (most of Afghanistan is higher than 6000 feet). The UV acted to keep the wounds sterile. So, is the current hysteria about UV overdone? I have also noted that a lot of teenagers with acne, find that it clears up in the summertime(when they are exposed to more UV). Is moderate sunning OK?
Well, UV may have some benefits, but it didn’t for me. 6 months after returning from a lovely 8 month vacation in the deserts of the Middle East, I got a nifty little sore on my face that wouldn’t heal properly, basal cell carcinoma, a mild form of skin cancer. After having it carved away by my doctor, I pretty much settled on getting my Vitamin D from milk, rather than sunlight.
Now, there may be something to the UV flux/germ theory, but at least for pale folks not living in the third world, I think the risks of UV exposure greatly outweigh the possible benefits. Moderate sunning is probably fine for most folks, but the only way to really know if it’s harmful to you is to develop skin cancer.
Is UV bad for you? Compared to what?
In any such discussion, we have to remember that we must consider what the alternatives are, and, often, were.
Is UV bad for you? Yes; there does not seem to be a genuine threshhold for UV WRT skin cancer[sup]1[/sup] and other negative effects. However, is getting a sunburn whilst working in the fields worse than actually starving to death? Not hardly.
[sup]1[/sup][sub]Of course, the most dangerous form of skin cancer, melanoma, appears to have only a modest correlation with UV exposure.
UV has been proved to cause DNA damage (pyrimidine dimers) in a dose related fashion. It has been correlated to skin cancer in people with fair skin. Australia and New Zealand are now battling through epidemic levels of skin cancer, due it is theorized to the sun-happy lifestyle and perhaps thinning ozone layer around that region.
Fair skinned people who spend a lot of time in the sun, particularly ones who have sustained severe burns (from UV) in early childhood are more prone to skin cancer. This has been tested over and over.
You need to separate sunlight from UV. The enzyme involved in vitamin D synthesis IIRC does not respond to UV light, and anyway, only miniscule doses of sunlight are required for its function. The story about infection in Afghanistan is no more than a correlation – lots of other things besides UV exposure are different between war wounded in Afghanistan and us.
While one one cannot dismiss it immediately, I would like a cite of his work. I doubt that the region is somehow sterile due to high UV, or that the wounds are exposed to any higher level of UV than wounds in the rest of the world.
Lastly, people in Victorian England were unhealthier than us for any number of a million reasons besides UV exposure. We have antibiotics, surgery, hygeine, bacterial theory of disease, etc.
There is probably nothing healthy about going out and getting a good tan.
In any discussion of the effects of UV light, it’s important to remember that the Ultraviolet Spectrum is divided into 3 general frequency/wavelength bands, each of which has markedly different effects on people:[ul][li]Ultraviolet A is the lowest frequency/longest wavelength band, and is the UV band which causes suntanning. The ozone layers (note the plural) in the outer atmosphere do not block out Ultraviolet A very well.[/li]
[li]Ultraviolet B is the next higher frequency/shorter wavelength band, and is the UV band which causes sunburns. The ozone layers do block out a substantial amount of Ultraviolet B.[/li]
Ultraviolet C is the highest frequency/shortest wavelength band. I don’t know what its effects on the skin or the eyes are, but I doubt it’s very good for you. The sun does not produce very much Ultraviolet C when compared to the other UV bands, and the ozone layers block out a substantial amount of Ultraviolet C.[/ul]It is not clear at this time whether UV A exposure or UV B exposure is more likely to cause skin cancer.
Kinda begs the question, doesn’t it? Aside from cultural conditioning, what evidence do you have that pale skin = unhealthy?
Eh, Fretful don’t be so fretful!
Cultural conditioning’s got nothing to do with it. All the pictures EG’s talking about were of 19th century Caucasians. Healthy Caucasian skin has a blush of health, and is colored “beige” or “peach” or “apricot”, whatever you want to call it, kind of a light-tan skin color. Unhealthy Caucasian skin is noticeably pale and pasty, whitish-colored. Pediatricians know when a Caucasian kid isn’t doing well because he’s pale.
So simmer down.