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Keith Jackson, Facebook asked:
I'm a depressive and I tend to develop SAD, so seasonal affective disorder, in the winter. Do the high-intensity light boxes that are supposed to allow the skin to generate vitamin D work?” So, those light boxes that you can go out and buy, and you can get yourself a dose of light for half an hour in the morning. Would that help to raise our vitamin D levels?
Well I think there are a variety of different kinds of light boxes, but I think just light unless it’s got an awful lot of radiation, it’s not going to generate any vitamin D so that I mean, people can go to – you know, they go to tanning salons and so forth and that will in fact generate vitamin D, but the downside of this of course is it may have the consequences of being exposed to sun.
So, the way around the dilemma, it seems to be, is if you want to increase your vitamin D content, then just simply take it by mouth as a regular vitamin D3.
I agree; the wavelengths of light emitted by lightboxes designed to combat SADs (seasonal affective disorders) are chosen to stimulate a population of cells in the eye that are not concerned with seeing but instead with setting the body clock. These specific retinal ganglion cells respond to light at about 480nm, which is present in the lightbox output.
It's possible in principle to have a light box that would do both SAD and UV-B, I mean sunlight does work, so a box that approximated sunlight, but with a lot less UV would do it, particularly if you wore appropriate eye protection (NOT sunglasses or tanning goggles, special goggles).
Far be it from me to disagree with Professor Ebers from Oxford but I took vitamin D3 supplements for 3 months, after which time, my very low levels had dropped a further 30%. My G.P.'s explanation was that taking the supplements had no effect because they were taken during three Winter months when my skin was not exposed to the sunlight. Therefore, only the precurser for true Vitamin D is made and not fully metabolised unless the skin is exposed. Therefore,simply taking the pills is not in my opinion, the answer to the problem. If this is incorrect, I am eager for a solution. Linda, Sun, 28th Oct 2012
And oral Vitamin D can cause kidney stones in those of us susceptible so still looking for an alternative to a Winter trip to the sun belt. LJSB, Sun, 23rd Dec 2012