Feel like ejecting a D debacle snippit this evening - the recognized experts in the field are all aligned on 32ng/ml being the minimum safe level, and PTH speaks to that also; arguably 40ng/ml would be a more optimal point. So what is the US population distribution - prize for the best guess is a properly functioning immune system!
No cheating - who got it?
Note: the horizontal % bars here show the observed percentage reductions associated with being HIGHER in 25(OH)D. For the cancer example, studies suggested being up at 38ng/ml might lower cancer rate by 35%, while being up at 52ng/ml might lower by up to 75%. Please do note that these are associational and case-control studies - they show that higher D tracks with much lower disease rates, but they don't PROVE that the D did it. But knowing the mechanisms now, and having studied widely, the preponderance of the data says that D has a strong causal nature in lowering disease like seen. In the seminar, I have a few actual experiments that illustrate the point, but sadly very few proper experiments have been carried out, at least the way I would have done them - with appropriate dosage, tracking of the physiological D levels attained, and proper control of the placebo group (it's amazing - some experiments gave tiny doses, and allowed everyone including placebo group to take D supplements willy-nilly).