Shawn,
First, Holick is the foremost vitamin D researcher in North America if not the world. While he's probably biased in favour of more Vitamin D, I wouldn't discount his recommendations lightly.
Second, IMO, it's impossible to give a "one size fits all" recommendation re exceeding the current safe upper limit of 2000 units daily.
If you're old, you're less efficient at producing D.
If you're obese, D is preferentially stored in fat making it unavailable for vital processes.
If you're dark skinned, you're less efficient at producing D.
Several foods are either fortified with D or naturally contain it.
I think that there's more than enough evidence showing benefits in being in the top half of the normal range. If you live north of Atlanta, get a test done, then decide what action, if any, is needed. If you're young, thin, light skinned living south of Atlanta and get outside daily with exposed skin that's not protected with sunblock, you're probably safe to ignore all this Vitamin D stuff.
Almost everyone else would benefit from taking a supplement.
Ian |
