It’s now quite clear that our ancestral vitamin D status was a lot higher than most citizens of the industrialized nations achieve today. A prudent person, knowing that, would strive to elevate his or her 25(OH)D level into that range by taking the amount of vitamin D needed to get back to ancestral status. The burden of proof should be placed on anyone who says we can get by on less.

Robert P Heaney, MD#

Professor, Department of Medicine, Division of Endocrinology, Creighton University