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According to University of the Wisconsin-Madison (UWM) Steenbock Research Professor of Biochemistry Hector DeLuca, vitamin D may indeed play some part in stopping MS from grabbing a hold on people. However, he proposes that UV wavelengths in the sunlight exert a more important influence on the disease. Details of his investigations, which were conducted with first author Bryan Becklund, were published in the latest online issue of the esteemed publication Proceedings of the National Academy of Sciences (PNAS).

“Since the 1970s, a lot of people have believed that sunlight worked through vitamin D to reduce MS. 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,” DeLuca says. He adds, however, that the new finding may not be helpful in any way. It is still too early to say whether the results will have any applications in humans or not.

Robert Furchgott and his colleagues noted as long ago as 1961 that exposure to light relaxed isolated arterial preparations,2 although other types of smooth muscle tissue were much less sensitive.3 The vascular photorelaxation was wavelength dependent, increasing as wavelength was reduced from the visible into the ultraviolet range and peaking at around 310 nm. In later experiments, Furchgott's group found that photorelaxation involved an increase in muscle cell cyclic GMP and that it was independent of the endothelium.4

As far as I am aware, Furchgott did not suggest on the basis of his work that ambient light intensity might affect the vasculature in vivo. Nonetheless, ultraviolet radiation can penetrate deep enough into skin to reach the microvessels,5 and the cutaneous circulation represents the site of a substantial proportion of total peripheral resistance. Although sympathetic tone has the most dramatic controlling influence on cutaneous vascular flow, it is not unreasonable to imagine that resting cutaneous vascular tone may under some circumstances also be tonically reduced by absorbed ultraviolet radiation. Withdrawal of this dilator effect when adapted individuals are translocated to a higher latitude could well increase total peripheral resistance and predispose to elevated blood pressure.

cheerleader wrote:My own honey has had basal cells cut off his body, he's a California boy with fair skin.