Are there any lamps out there that produce enough UVB in the 290-300 nm wavelength so as to produce natural Vitamin D production in the skin? I'm cooped up inside most of the day studying and I'm concerned about my vitamin d production (and I do not really like taking supplements when I don't have to).
just get online and research fast food restaurant suppliers. Compare prices on those heat lamps they use to keep the food warm. Get some cheap ones and put them all over your bedroom. Sleep naked underneath them at night. You'll be so full of vitamin D that it'll be ridiculous. Also you'll be tan as shit... that'll be way better for you than taking a simple vitamin once a day.
Beyond all of that, as a rule I am more comfortable with a substance that endogenously produced (and therefore regulated by my natural biological mechanisms) than taking a supplement. Evolution has crafted the body pretty well, so I prefer the natural system over the artificial one.
A good deal of info here: http://www.solarcsystems.com/narrowband_uvb.html Honestly, gregron has a point that Vit D3 is easy and cheap. But narrowband lamps can be a good option is you don't respond well to pills, which may be the case with some ppl (try pills and then get tested b4 you try a lamp though).
I bought my vitamin D lamp from the vitamin D council, as already listed above. I like it! I guess more than just D3 is manufactured in the skin with UVB rays strike them. 5 to 10 other compounds are made too that are little understood but thought to be important. So found it good to take D3 supplements and some exposure to a lamp a couple times a week, in my personal case.
You might find some information about lights here also, not for sure though.
Are you vitamin D deficient? If you are not you don't "need" to supplement. Get your level tested. If you ARE deficient oral supplementation makes the most sense. I supplement orally and in the summer have the Dr.'s green light to lay out an hour a day a few times a week.