Roger Bouillon

Emeritus Professor of Medicine at KU Leuven. Author of foundational work on the physiology of vitamin D binding protein, on the pleiotropic effects of the vitamin D endocrine system beyond bone, and on the discrepancy between the thresholds needed to prevent rickets and the thresholds compatible with adequate innate immunity, muscular function and metabolic regulation.

Why he matters here

Bouillon is one of the mainstream European voices whose work is regularly cited on both sides of the reference-range dispute. That the dispute is unresolved, in a nutrient this well-studied, is itself the argument. If the target concentration for a hormone-like molecule cannot be settled after four decades of intensive study, the fault lies not in the nutrient but in the framework that treats reference ranges as descriptive rather than normative.