It’s known that vitamin D is necessary for proper bone formation and maintenance. But recent decades have seen a torrent of studies suggesting that vitamin D can also affect many other aspects of health; some scientists have come to consider the daily recommended intake of 400 international units of vitamin D far too low. Michael Holick is a biochemist and endocrinologist at Boston University who has spent a career researching the effects of vitamin D (which is actually not a vitamin but a hormone precursor). His new book is The Vitamin D Solution (Hudson Street Press, 2010). Holick recently spoke with Science News biomedicine writer Nathan Seppa.
How much vitamin D do we need?