June 23, 2014
New Study Suggests That People Could Become Addicted To Sunbathing
redOrbit Staff & Wire Reports - Your Universe Online
Sunbathing can be addictive, producing the same kind of chemical reaction in the brain as illicit drugs like heroin, according to new research that could help explain why some people seem to crave UV rays, despite the risks.
Mice who were regularly exposed to UV light also demonstrated a higher pain tolerance than those who did not receive such exposure, said Deborah Netburn of the Los Angeles Times. They also appeared to experience withdrawal symptoms when the rays were taken away, reacting comparably to having been given low doses of heroin.
“I know people are thinking, heroin and UV radiation, give me a break,” lead investigator David Fisher, a dermatology professor at Harvard Medical School and Massachusetts General Hospital, told Netburn on Friday. “But we think there could be evolutionary reasons for it.”
According to the Daily Mail’s Fiona Macrae, Fisher and his colleagues gave the mice a dose of UV light equivalent to 20 to 30 minutes of midday Florida sun every day for a period of six weeks. Within just one week, the endorphin levels of the rodents increased, as did their tolerance to pain.
Afterwards, they were given drugs that prevented endorphins from functioning, and the researchers found the mice started developing symptoms of withdrawal, including trembling and chattering teeth, Macrae added. Furthermore, the mice made a concentrated effort to avoid the area where they had been given the drug.
Fisher believes that the addiction could have evolved as a way to make sure that a person was getting enough vitamin D, which is manufactured by the body when our skin is exposed to sunlight. Macrae said that vitamin D has been credited with preventing Alzheimer’s disease, maintaining heart health, slowing prostate cancer and preventing the development of multiple sclerosis, but noted that it can now also be obtained through supplements.
“I would say at this stage, with reasonable confidence, that this pathway really does exist and is probably present in everybody,” Fisher told BBC News health and science reporter James Gallagher. “It sounds like a cruel joke to be addicted the most ubiquitous carcinogen in the world, it is plausible that there is an evolutionary advantage and we suspect that may relate to vitamin D.”
Other scientists, however, aren’t convinced by the study. University of Cambridge addiction researcher Dr. David Belin told Gallagher that the conclusions of the Harvard study “are not supported by their results, since truly UV-addicted mice would have demonstrated that they preferred spending time under the lamp to all other activities, including eating. The study shows no evidence of this."
While Belin called the research “outstanding,” he added that people who were truly addicted to sunbathing would be “giving up their family lives to get access to sunshine, you would have people who lose their jobs because they spend their day on the beach, people would maintain UV-seeking behavior to the detriment of their everyday life.”
“This study does not provide the sort of evidence needed to show addiction to UV light in mice and it is even less certain that the work predicts addiction in humans,” added Dr. Clare Stanford of University College London. “This would require testing whether the mice preferred UV light or non-UV light, which was not done in this paper.”