Vitamin D is liposoluble vitamin that is created in the organism by exposure to ultraviolet (UV) rays from the sun, by using certain types of food, or by using certain supplements in the form of Vitamin D3  (Cholecalciferol) or Vitamin D2 (Ergocalciferol).

Basic physiological function of Vitamin D is maintaining the serum concentration of calcium and phosphorus on the level that supports the cell processes, neuro skeletal function and bone formation. Therefore vitamin D has important role in the growth and development, the normal mineralization and bone maintenance and good teeth health. At the same time the vitamin D is important for normal muscle function. This vitamin has important role in regulating the cell division and differentiation.

Vitamin D also has important role in regulating the function of the immune system and the immune response. It is particularly important to pay attention to the regular and adequate administration of Vitamin D in the periods when sun exposure is limited. Adequate usage of this Vitamin is important for children in the period of growth and development. Vitamin D is important for older people as well diminishing the risk of bone fracture.