"The ideal blood level of vitamin D was roughly between 50 to 100, with 70 nmol/L being the optimal level."
"the optimal level" ? ? ? Optimal for whom ? ? Does he mean the highest frequency in those living longest in that (large) "prospective" study group - if so, that's not the same as the "optimal" - a wrong choice of word, perhaps ?
Like any/all(?) HORMONES too much is more than likely to be as bad as too little, Goldilocks !
Holick, a big calcium supplement-recommending "cheese" in the "vit D" world artificially holds his blood level of 25(OH)D3 at 125nmol/L ( - if I recall correctly).
BEWARE: TOO much calcium will shorten life; most of us who drink milk & eat cheese, get enough according to Prof Veith, another "vit D" expert, who supplements with "only" 25mcg/day (= 1000IU) - but what blood level does that give him thru' summer & winter, I wonder ? ? ? No doubt over 50nmol/L, but maybe not over 100, at its lowest late winter, point ? ? ?
[Many more of us, who drink milk & eat cheese are more likely to be short of MAGNESIUM, which tis' said, is best supplemented with Mg FLAKES ( - either sprayed on skin, or added to drinking water). Came across an INTERESTING view recently that cells with inadequate T3 cannot use the magnesium, & so split it out - would love to see a citation for that; anyone come across it already ? ? ?].
Yet, some of us ( - for reasons I'm still hoping to understand better) can't get their blood levels into the 80s with hugh supplementation with (or without) feeling ILL. Any clues on this "endocrinological ceiling" ? [Inadequate supplies of other hormones or nutrients ?]. Researched pointers or wild guesses more than welcome !