A Mathematical Model for Determining the Body’s Fluctuating Need for and Synthesis of Active Vitamin D

Abstract

The process by which 1,25(OH)2D3 is synthesized and degraded and how it is transported out of the cell and body is described. The changing demand for the synthesis of 1-25(OH)2D3 during different conditions experienced by the body is reviewed. A method of determining 1,25(OH)2D3 synthesis and demand, and the percent utilization of 25(OH)D3 to make 1,25(OH)2D3 is presented based on the measurement of the end metabolites of 1,25(OH)2D3 and of its immediate precursor, 25(OH)D3. A mathematical model has been developed to allow the calculation of 1,25(OH)2 D synthesis, and demand, and the percent utilization of 25(OH)D3. Simple algebraic equations have been derived which allow the calculation of these new parameters using the concentrations of the end metabolites of 1,25(OH)2D3 and its immediate precursor, 25(OH)D3 in the serum and urine. Vitamin D plays an important role in combating invading bacteria and viruses and in subduing the body’s associated inflammatory response. This new approach to evaluating vitamin D status may help clinicians determine 25(OH)D3 and 1,25(OH)2D3 levels needed to suppress bacterial infections, viral replication during new viral infections and the reactivation of latent viruses, and to downregulate the inflammatory responses caused by bacteria and viruses.