Vitamin D, also called ” sunshine vitamin “, is essential for the proper functioning of the nervous, vascular and immune systems. Our body can produce it itself under the influence of the sun, but it is a very complicated process and even in the summer we may suffer from its deficiency. Regular supplementation with vitamin D regulates the calcium-phosphate metabolism in the body, or key elements for the condition of teeth, bones and joints. It is also necessary in the prevention of osteoporosis. Vitamin D helps to absorb calcium and transport it to the bone. It is very important because thanks to this the bones retain the right density. Another important feature of vitamin D is its effect on glucose. Its deficiency may cause disturbances in the level of sugar in the blood, and this poses the risk of diabetic complications. In addition, it has an activity supporting the building of muscle mass. This is because it is involved, among others, in the synthesis of testosterone, which is an anabolic hormone. So that’s why it is important to provide the body with the right dose of vitamin D. Unfortunately, the conditions prevailing in Europe are conducive to shortages of this vitamin.