American Journal of Clinical Nutrition, Vol 22, 437-446, Copyright © 1969 by The American Society for Clinical Nutrition, Inc.

Absorption and Metabolism of Vitamin D₃ in Man

¹ From the Department of Medicine, Jewish Hospital of St. Louis and Washington University School of Medicine, St. Louis, Missouri

Five decades following the recognition of the antirachitic properties of sunlight, renewed interest in the metabolism of vitamin D in man is proceeding at an accelerated pace. Incited by provocative demonstrations in laboratory animals and assisted by refinements of both biochemical methodology and radioisotopic synthetic techniques, the clinical investigator has proceeded in rapid succession to define the manner by which vitamin D is normally absorbed from the intestine, its metabolic conversion to a potent biologically active metabolite, and the deranged absorptive as well as altered metabolic patterns in some disorders of calcium and bone metabolism. Despite these achievements many lines of investigation may still be profitably followed since present concepts of vitamin D secretion, metabolism, and biological action are still inadequately defined in man.