The body naturally produces vitamin D when exposed to direct sunlight.
However, the actual exposure to UV rays and the synthesis of vitamin D depend on many factors (for example, seasons, situation, time, age, smog or the darkness of the skin).
Vitamin D is found naturally in foods as vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol), but it can also be taken as a supplement.
Vitamin D contributes to the normal functioning of the immune system and muscles, to the maintenance of normal bones and teeth, and also to the normal absorption and utilization of calcium and phosphorus.