The old conservative dose rule of thumb is 400 IU per day.... like in a typical multivitamin pill. The latest studies say 1000 IU or more per day is needed to maintain ~80 nmol/L of circulating D3. Holicks book also says so. However they caution against swallowing lots of pills because too much analog D can be toxic.
Vitamin D resulting from photoconversion of 7-DHC by UVB light however has not been shown to be toxic. In fact the body begins to self-regulate levels of D after 1.5-2 MED exposure.
Isl Cove: A 1 MED dose of UVB has been shown to result in 1000 IU of D3 on 10% body exposure per in vivo tests of percent conversion of 7-DHC by many vitamin D scientists. The meter is basically reading 16.667 IU/min per MED/hr... which works out to the same conversion rate.
You guys are making me get complicated not simple!
Bottom line is the meter actually quantifies a positive effect of UV.
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