Physiological needs and effective doses of vitamin D for deficiency correction. Current state of the problem

Abstract

In addition to classic role of vitamin D in musculoskeletal health over the last decade it was shown that low blood serum concentrations of 25(OH)D are associated with a number of non-skeletal disorders including cancer, high blood pressure, age-related cognitive decline, disorders of the immune and reproductive systems, etc. The prevention of the development of these diseases is reached under considerably higher concentrations of the vitamin in the blood serum, than is necessary to maintain the normal state of the bone tissue, to regulate calcium absorption and homeostasis. To maintain the concentration of the circulating form of vitamin D 25(OH)D in blood serum at a level ensuring optimum course of vitamin D-dependent biochemical processes (greater than 50 nmol/l), a higher intake of vitamin D is necessary. Reduced blood concentration of vitamin D (less than 30 ng/ml) occurs in 50-92% of the adult population of working age in our country, regardless of the season. The causes of vitamin D deficiency are the low efficiency of its endogenous synthesis in the skin due to insufficient sun exposure owing to the geographical position of our country, and inadequate intake of the vitamin from food as a result of rare consumption of the main source of this vitamin - oil-rich sea fishes. In the Russian Federation the current daily norm of physiological need (10 mcg) to some extent allows to maintain skeletal features, but such consumption does not allow to achieve adequate levels of the circulating form of vitamin D in the blood, which provide optimal manifestation of nonskeletal functions of this vitamin. The analysis of the available information and the prevalence of vitamin D deficiency point to the need to increase the physiological needs of vitamin D to 15 micrograms (600 IU/day). Simultaneously it should be recognized that vitamin D daily intake of 25 micrograms (1000 IU/day) is an effective dose to improve vitamin D status and at the same time is safe. Higher vitamin D intake can reliably eliminate the existing deficit of this vitamin in the population and maintain blood concentration of 25(OH)D at an optimum level, which will provide health benefits.