Given the numerous warnings linking sun exposure with skin cancer, why do so many people still worship the sunshine?
According to new research published in the journal Cell, it may be because our bodies become addicted to the feel-good hormones that are released through exposure to ultraviolet (UV) radiation. This craving may guide individuals to actively seek out UV rays, which are well known to increase a person’s risk for skin cancer and melanoma. According to the American Cancer Society (ACS), 76,100 new cases of melanoma will be diagnosed in 2014.
It has been suggested that heavy outdoor or indoor tanning habits qualify under psychological criteria for addiction-like behavior. Researchers speculated that exposure to UV radiation triggers the release of hormones called endorphins, which help relieve pain by activating opioid receptors – the same receptors activated by prescription painkillers, morphine and heroin.
For their study, Fisher and his team exposed shaved mice to UV light for six weeks in low doses. After one week, measured endorphin levels in the bloodstream increased. The subjects were then tested for common symptoms associated with opioid signaling – such as low sensitivity to touch and temperature – and the researchers found the mice had become numb to sensory input. When the mice were put on an opiate-blocking drug, to lessen the effects of the increased endorphins, the numbness was instantly reversed.
“It was the first clue that UV radiation was affecting real opiate signaling to the level of being able to perceive or act on a sensory input,” Fisher, who is also director of the melanoma program at the MGH Cancer Center, said.
In another experiment, when UV-exposed mice were put on an opioid-blocking drug, they had withdrawal symptoms including shaking, tremors and teeth chattering, suggesting chronic UV exposure leads to physical dependence and addiction-like behavior.
Study authors equivocated chronic exposure to UV radiation in their study to approximately 20 to 30 minutes of ambient midday sun exposure in Florida during the summer, for a fair-skinned person of average tanning ability.
To further study the UV exposure and endorphin connection, researchers wanted to know whether the subjects’ behavior could be influenced by cognition of withdrawal symptoms.
“In a human population, if you wake up on a gorgeous sunny morning, you have the choice of going to the beach and getting heavy UV exposure or saying you’re not going to do that because you know it’s bad for you; we have a choice,” Fisher said. “We wondered when mice were exposed to this type of effect, does it reach a point where it actually motivates them to behave in a fashion we could actually measure.”
After being given opioid-blocking drugs, the UV-exposed mice actively avoided conditions under which they suffered withdrawal symptoms, the researchers found. For the general population, this finding may mean a different approach is needed to convince people to avoid hazardous UV exposure.
“From a public health perspective, it’s important because it suggests, to break the UV exposure pattern – which is probably partially responsible for the skin cancer incidence we see – maybe it’s more than telling you, ‘The sun is bad for you and associated with skin cancer,’” Fisher said. “Maybe we need to be imparting the message on a deeper level, toward, ‘You may be actually opiate-addicted to some degree.’”
One solution may be to better legislate access to indoor tanning beds, especially for teens.
“To the extent these are currently being regulated as cosmetic devices with wide open access, when we’re dealing with something that is opiate stimulating, that’s a place we should be dealing with more strongly,” Fisher said.
As for the belief that our bodies “need” sun exposure to produce essential vitamin D, Fisher noted that the “argument really doesn’t hold water anymore.” While vitamin D is vital for bone health and calcium regulation, getting it from the sun isn’t a safe method, he said. Plus, a wide range of variables such as time of day, location, clothing, season of the year, and skin pigmentation, make sunlight an unreliable source.
“You’re essentially taking vitamin D with a carcinogen,” he said. “Even more than that, as a doctor, if a person’s vitamin D level is too low, it’s not even a reliable way to maintain vitamin D level.”
Heard them saying something like this on the news this morning.
the second link may offend some due to certain language.
Very strange article. Sometimes common sense is more valuable than published research. Perhaps in this day it always is. Man was made to live outdoors, under the sun. The body does not produce vitamin D without it and the endorphins which are produced as a result of sun exposure were designed in such a way by the Creator so that mankind would recognize the body's need for that light, just as satiation of hunger tells the body that sustenance has been taken an it is good. A lack of sunlight has drastic negative effects on the brain's chemistry including depression and cognitive dysfunction.
Tanning beds do not have the same effect, as the light spectrum is limited and the full spectrum which comes only from natural light is needed for the synthesis of vitamin D and subsequent hormone production.
Skin cancer is found as often in very dark skinned people as very light skinned people and the higher instances of those dark skinned people getting skin cancer occurs in northern latitudes where the sunlight is weaker. This would point to the fact that skin cancer is related to a lack of vitamin D production.
While light skinned people exposing themselves to the sun until their skin burns can result in temporary damage, and a lifetime of intentional over-exposure can cause chronically dry and damaged skin, normal exosure to the sunlight is critical for the health of people of all skin tones.
It is ironic that such a view would come from the scientific community which is avidly athiestic and believers in evolution. If their claims about sunlight were correct then their evolutionary theory fails as well, because humans would have naturally evolved as a nocturnal species rather than a diurnal species if sunlight were "toxic" to them.
This, along with many other published health theories from the scientific community are aimed at promoting habits which will interfere with health, not benefit it. It is, and has always been the direct agenda of this group to promote chronic states of disease which continually need treatment, providing a customer base for doctors and drug makers.