Wednesday, April 11, 2007

Addiction to tanning?

Summer is coming in the northern hemisphere, which means, perhaps, more time in the sun. We had a look here at the surprising role that the anti-cancer protein p53 plays in tanning. Beyond that, we know that getting a tan feels good, if not overdone (so to speak).

(And by the way, studies like this one have shown that vitamin D, which is a byproduct of tanning, has beneficial anti-cancer effects for breast and colorectal cancer, in spite of the risk of melanoma from too much UV exposure. Other studies show protective effects of vitamin D for ovarian cancer, pancreatic cancer, and prostate cancer too.)

Anyhow, it seems that some people can't get enough sun tanning, in spite of the risks. Perhaps it's addictive:

New Study Indicates Tanning May Be Addictive
Despite repeated health warnings about the dangers of tanning from sunlight and artificial light sources, there are still those whose mantra “bronzed is beautiful” remains unshaken. Dermatologists have long suspected that some people may be addicted to tanning – similar to addictions to drugs or alcohol – and refuse to alter their behaviors, even knowing they have an increased risk of developing skin cancer. Now, a new study of college co-eds indicates that some people may be addicted to ultraviolet (UV) light.


Why would this be? Most likely for the same reason that the process of getting a tan feels good. Dermatologist Robert Hornung, who led a questionnaire study to investigate the motivations of dedicated tanners, explains:
“We also know from previous experiments that UV light causes endorphin release, similar to the euphoric sensation associated with intense exercise commonly referred to as ‘runner’s high’ or other pleasure-seeking behavior. Our study set out to find whether certain individuals, particularly those who classify themselves as frequent tanners, exhibit addictive behaviors toward tanning.”

However, it's not clear from what's reported here whether frequent tanners have an actual chemical dependency to their own endorphins. For instance, do they have withdrawal symptoms if they stop tanning abruptly? Are there other signs of a biochemical effect?

Perhaps its time to head to Maui to do a little more research... Or perhaps the nearest nudist resort would be a good choice for some field work. I'd volunteer. Wonder where to apply for a grant...

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4 Comments:

Blogger bioglobin said...

Hello

Nice blog! Are U a science profeshional, I wonder. Anyway I like it. Hope you don't mind if I add your blog in my list.

Oh! if you like science new, I normally read from this one:
http://www.sciencedaily.com/

See you then

4/12/2007 12:08:00 PM  
Blogger Charles Daney said...

Thanks. I'm glad you like the blog. Of course you may add it to your list. And yes, Science Daily is very useful.

4/12/2007 01:20:00 PM  
Blogger David Bradley said...

Public health is being put at risk by official policy in temperate climes (e.g. UK) that discourages sunbathing and promotes the use of sunblock products. The cost of disease (cancer) caused by insufficient exposure to sunlight and consequent deficiency of vitamin D has been estimated as being in the billions.

http://www.sciencebase.com/sunshine.html

4/23/2007 01:01:00 AM  
Blogger Charles Daney said...

Public health is being put at risk by official policy in temperate climes (e.g. UK) that discourages sunbathing and promotes the use of sunblock products.

I'm inclined to be skeptical of these claims that discouraging sunbathing puts public health at risk. The report, on which the article that David cites is based, was published by a UK organization called the "Health Research Forum". The author of the report, a journalist named Oliver Gillie, is also one of two members of the "advisory board" that runs the organization. It does not appear that Gillie has professional scientific or medical credentials. His organization seems to be dedicated to promotion of sunbathing. That's all well and good, except his report charges that standard cautions regarding sunbathing are "based on a major error, mistaken assumptions and wishful thinking."

One of the issues is that exposure to sunlight enables the body to produce vitamin D, which is beneficial in various ways, and without which a person is more susceptible to cancers of various types. That much seems to be well established by research. However, sunbathing isn't the only way to acquire the necessary vitamin D. Milk (at least in the US) is usually fortified with vitamin D. And if that's not enough, taking common vitamin supplement pills is an easier and (probably) a safer way than sunbathing to get vitamin D.

The second issue with Gillie's "report" appears to be an obfuscation of the dangers of skin cancer as a result of sunbathing. The dangers seem to be played down on the basis of noting it is a "mistaken assumption" to equate England and Australia. Well, sure. They certainly don't receive the same intensity of sunlight on average. But deliberate longer exposure to sunlight in England in the process of sunbathing will make up for the lower intensity of the sunlight. If you get the same amount of UV exposure, you'll run the same risk of skin cancer – which is certainly not negligible, given long exposure.

Perhaps Gillie is mainly concerned to dispute public health recommendations in England that are unreasonably cautious. I don't have enough familiarity with the situation to judge that. But I do find it hard to go along with the idea that "To ensure optimum levels of vitamin D and optimum health people in the UK need to sunbathe whenever they can wearing as few clothes as possible while taking care not to burn."

"Whenever they can" seems a bit strong, when there are simpler, easier, and safer ways to get vitamin D. And I think there are nontrivial risks of skin cancer from too much UV, even if one avoids actually getting burned.

4/24/2007 02:23:00 AM  

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