--but he is right; this is a very hot topic in medical nutrition right now, with a lot of disagreement and no clear consensus as of yet.

A number of researchers/commentators have been indicating that the tremendous emphasis on keeping away from ultraviolet sun exposure has been leading to a generation of people with suboptimal Vitamin D levels; others disagree and say, given the reduction in ozone layers and the protection from burning rays these provide, it is necessary to severely limit sun exposure to prevent skin cancers. The first group often counters that the drop in immune system efficiency associated with low Vitamin D levels is more dangerous than the possibility of skin cancer. Many in this cmap also believe that many of the current lab ranges for acceptable Vitamin D levels are themselves suboptimal, not unlike the arguments that have been made about lab reference ranges for B12. And the arguments go on.

Ted Hutchinson, who posts at the Braintalk boards, has accumulated a vast databse of these papers and arguments for anyone who wants to wade through them (and it is a lot of material--sort of analagous to what Paul and Rose here have done for B12, and Mrs. D has done for magnesium and calcium):

http://brain.hastypastry.net/forums/...ead.php?t=2822

My own take on this, overall, is that since I am very fair-skinned and freckle easily, I have to really watch sun exposure more than most, so I am wary of low D levels and try to supplement with cholecalciferol (D3--the more effective, mg per mg, variety, which is also the form our skin makes), especially during the winter months. The biggest problem I have is getting physicians to realize the value of ordering Vitamin D assays.