[quote="Crider"] There are absolutely zero studies showing harm from daily supplementation of a useful amount of D.
I don't consider 'lack of harm' to be a valid recommendation. Still, like nutrition in general, this is a VERY complex issue, of which science is yet only scratching the surface.
This video lecture by Dr. Bruce Hollis describes a model of how vitamin D is used at a cellular level by our bodies for such things as immune function and how its half-life of only 24 hours is another reason why daily doses of vitamin d make so much sense.
There may well be something to the possible extra benefit of DAILY sun exposure, but Vit. D produced by the body is likely NOT the same as a synthetic supplement. It may well function differently, and half-life measurements may not relate. However, the all too common refrain encountered when searching for relevant studies: ("vitamin D deficiency has become a global epidemic"!!) reminds me to remain suspicious on this subject. The vitamin D research industry has apparently become a major employer, and it seems every study ends with: "more research is needed".
Here's a
video rundown by Cedric F. Garland
Dr. Garland's body habitus makes it quite obvious that 'dietary health' is not near the top of HIS priorities! It's relationship to disease and (OH)D status is never mentioned. The most interesting aspect of his lecture was the comment at the very end re: a BMJ article supposedly suggesting that inflammatory disease DOES NOT accelerate (OH)D metabolism (which would be contrary to Dr. McD.'s supposition). I found plenty of data online about Vit. D's effect on inflammation, but nothing on the reverse.