Vitamin D and Its Importance for the Metabolism

Vitamin D, accept as a steroid hormone, is an ergosterol (vit-D2) of plant and animal origin. It is classified as cholecalciferol (vit-D3) derived from 7-dehydrocholesterol in the skin. Vitamins D are also called as calciferols. Vitamins D2 and D3 are metabolised in the same way, and at first, they are converted to 25-(OH) D3 in the liver, then they are migrated to kidney and converted to 1,25-(OH)2 D3 is an active form of vitamin D. Vitamin D has many functions in metabolism, particularly in osseous and skeletal system. By having a part in calcium and phosphor metabolisms, it enables them to be absorbed in the intestines. It has also protective effects against a number of diseases and cancer types. Hypovitaminosis D manifests itself generally as bone and skeletal system disorders in metabolism. The most frequently observed diseases related to hypovitaminosis D are mainly the rickets in children and osteomalacia in adults. Limited exposure to the sunlight is among the most important reasons lying behind hypovitaminosis D. Further, the excessive intake of vitamin D leads to toxic effects and irreversible problems in the metabolism.