Imagine you are a doctor and a 49-year-old patient with kidney failure comes to the emergency room with dangerously low blood calcium levels. He is taking activated vitamin D and calcium but still his blood calcium is perilously low.
This actually happened to Dr. Karin Amrein, of the Medical University of Graz, working with Professor Harald Dobnig, who not only helped the patient, they discovered what some had only previously suspected about vitamin D and calcium absorption.
Amrein K, Worm HC, Schilcher G, Krisper P, Dobnig H. A Challenging Case of Hypocalcemia Supporting the Concept That 25-Hydroxyvitamin D Status Is Important for Intestinal Calcium Absorption. J Clin Endocrinol Metab. 2012 Mar 14.