Dvitaminban

Dvitaminban, commonly known as vitamin D, is a fat-soluble secosteroid essential for calcium and phosphate metabolism and bone health. It exists in two major dietary forms: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). D3 is produced in the skin from 7-dehydrocholesterol upon exposure to UVB radiation, while D2 is derived from plant sources and fungi.

After absorption, Dvitaminban is transported to the liver where it is hydroxylated to 25-hydroxyvitamin D [25(OH)D], the main circulating form used to assess status. It is then converted in the kidney and some other tissues to the active hormone 1,25-dihydroxyvitamin D [1,25(OH)2D], which binds to the vitamin D receptor to regulate genes involved in calcium and phosphate homeostasis and bone mineralization.

Functions extend beyond bones to influence immune function, muscle health, and cell growth regulation, though evidence for non-skeletal effects varies.

Deficiency can lead to rickets in children and osteomalacia in adults, and may be associated with increased fracture risk. Risk factors include limited sun exposure, living at high latitudes, dark skin, malabsorption, kidney or liver disease, and older age.

Intake recommendations vary by country; general guidance often suggests daily intakes of a few hundred to about 800-1000 IU for adults, with higher doses for those at risk of deficiency. Vitamin D toxicity is rare but can occur with very high intakes, causing hypercalcemia.