Forum Diagnosticum No.05/2012
25(OH)D, Insulin Resistance and Inflammation in Men with Central Obesity
25(OH)D is a fat-soluble vitamin that will be trapped in fat cells if one is overweight or obese and results in the decline of the bioavailability of vitamin D. The changes on calcium and vitamin D homeostasis are related to insulin resistance, beta cells dysfunction, metabolic syndrome, impaired glucose tolerance and DM. Vitamin D can affect the activity of insulin either directly by stimulating the expression of insulin receptor, or indirectly by its roles in regulating extracellular calcium, as well as ensuring that the calcium influx passing through the cell membrane is normal and that the amount of intracellular cytosolic calcium is sufficient. Moreover, vitamin D can repair insulin sensitivity and secretion, improve endothelial vasodilation, as well as hamper coagulation and inflammation activity. Thus, the low concentration of vitamin D may reduce the ability of calcium to affect insulin secretion.
Author: Anggi Kartikawati (PT Prodia Widyahusada)