Vitamin D Deficiency and its Importance - A Global Problem of Today, Realistic or Not?

Vitamin D, also known as the “sun vitamin” in the literature, has been examined for many years and still arouses researchers’ interest due to the pleiotropic effects achieved in the human body. Because of the influence on mineral homeostasis, the initially observed effects of vitamin D on the prevention and treatment of rickets, have now been extended to a large number of diseases with different aetiologies such as cardiovascular, autoimmune, endocrine, infectious, neurological, malignant and other diseases. Due to the large number of experimental studies in animals and humans, we have exact information about the role of vitamin D in many of these conditions. Reaching an adequate level of 25(OH)D in the human body is a basic requirement for the realization of these effects; 25(OH)D is a metabolic product that reflects the vitamin D status but that does not have any biological activity. The biological activities of vitamin D can occur only after the formation of a second metabolic product, 1,25(OH)₂D, in the kidneys. The three main sources of acquiring vitamin D are through food, skin and supplementation. Food is not a rich source of vitamin D; it is clear that the most important influences to achieve an optimal vitamin D status in the human body are vitamin D synthesis at the skin and adequate supplementation intake. An alarming fact is that vitamin D deficiency is detected in an increasing number of people from one day to another in the general world population and that this condition has pandemic dimensions. Introducing the beneficial effects and sources of vitamin D to the general population and to medical experts with adequate supplementation regime can decrease the number of people who are vitamin D deficient.