(NaturalNews) It's not a new idea that multiple sclerosis (MS) is somehow tied to sunlight -- or, rather, the lack of adequate exposure to sunlight. For more than three decades, researchers have noted that MS is much more common in higher latitudes than in the tropics. So, because bright sunlight is more abundant near the equator and sunlight exposure results in the body producing vitamin D, some scientists have reasoned that increased vitamin D levels may lower the risk of MS.
In fact, for those who already have MS, a neurological disease marked by a deterioration in nerves' electrical conduction, vitamin D may reduce their symptoms, according to Hector DeLuca, the Steenbock Research Professor of Biochemistry at University of Wisconsin-Madison. However, in a study just published in the Proceedings of the National Academy of Science (PNAS), DeLuca and fellow researcher Bryan Becklund conclude the ultraviolet (UV) portion of sunlight could play an even more important role than vitamin D in preventing and/or controlling the MS.
"Since the 1970s, a lot of people have believed that sunlight worked through vitamin D to reduce MS," DeLuca, one of the world's top vitamin D researchers, said in a statement to the media. "It's true that large doses of the active form of vitamin D can block the disease in the animal model. That causes an unacceptably high level of calcium in the blood, but we know that people at the equator don't have this high blood calcium, even though they have a low incidence of MS. So it seems that something other than vitamin D could explain this geographic relationship."
To try to better understand the impact sunshine could have on MS, Deluca and his team worked with lab mice that are genetically bred to be susceptible to a MS-like disease. The researchers triggered the disease in the animals by injecting them with a protein derived from nerve fibers. Then the mice were exposed to moderate levels of UV radiation (UVR) for a week. After the lab rodents developed multiple sclerosis-type symptoms, they were exposed to UVR every second or third day.
The UV exposure, which was equal to about two hours of direct summer sun, did not change how many mice got an MS-type illness, but it did reduce the symptoms of MS. Symptoms were especially reduced in the animals that were treated with UV light ever other day.
While the scientists found that although the UV exposure did increase the level of vitamin D in the mice, that effect by itself wasn't enough to cause such a dramatic lessening of MS symptoms. "These results suggest that UVR is likely suppressing disease independent of vitamin D production, and that vitamin D supplementation alone may not replace the ability of sunlight to reduce MS susceptibility," the scientists concluded in their paper.
In a media statement, DeLuca pointed out that the exposure to UV light might result in some reactive mechanism that blocks the autoimmune damage seen in MS. "We are looking to identify what compounds are produced in the skin that might play a role, but we honestly don't know what is going on," he said. "If we can find out what the UV is producing, maybe we could give that as a medicine. In the short term, if we can define a specific wavelength of light that is active, and it does not overlap with the wavelengths that cause cancer, we could expose patients who have been diagnosed with MS to that wavelength," DeLuca added.
Editor's note: NaturalNews is opposed to the use of animals in medical experiments that expose them to harm. We present these findings in protest of the way in which they were acquired.