I'm glad this was posted, although I do find the article to be a little confused.<p>Certainly, what the writer is getting at has been the Achilles heel of the whole take-your-vitamins movement: just because some chemical is good to have in your body, does not mean that taking that chemical in pill form is a helpful thing. While she does not mention it, this idea seems to be particularly applicable to vitamin C. It is certainly an important part of general health. However, if I understand the research correctly, beyond the small amount necessary to prevent scurvy, studies have shown no benefits at all to taking vitamin C supplements (corrections are welcome!).<p>So: the first few paragraphs suggest that, while high vitamin D levels seem to correlate with good health, that does not mean that supplements help. Correlation does not equal causation, etc.<p>That is all fine. However, she then goes on to cite studies, <i>all</i> of which were concerned not with vitamin D levels in the body, but with supplementation.<p>Furthermore, she rather strangely says that the Women's Health Initiative study "found no overall benefit", and yet also found that vitamin D + calcium supplementation correlated with reduced incidence of hip fracture. How is that not a benefit?<p>In any case, I welcome the direction that research seems to be going. Whenever there is an easy way to improve the health of large numbers of people, it is a good idea to find it.