Vitamin D

Abstract

Vitamin D has received a lot of attention recently as a result of a meteoric rise in the number of publications showing that vitamin D plays a crucial role in a plethora of physiological functions and associating vitamin D deficiency with many acute and chronic illnesses including disorders of calcium metabolism, autoimmune diseases, some cancers, type 2 diabetes mellitus, infectious diseases and cardiovascular disease. The recent data on vitamin D from experimental, ecological, case-control, retrospective and prospective observational studies, as well as smaller intervention studies, are significant and confirm the sunshine vitamin’s essential role in a variety of physiological and preventative functions. The results of these studies justify the recommendation to improve the general vitamin D status in children and adults by means of a healthy approach to sunlight exposure, consumption of foods containing vitamin D and supplementation with vitamin D preparations. In general, closer attention should therefore be paid to vitamin D deficiency in medical and pharmaceutical practice than has been the case hitherto.

Vitamin D in Oxidative Stress and Diseases

“…Recently, vitamin D 3 deficiency has been connected with sarcopenia (age-related loss of muscle mass) mainly of type II skeletal muscle fibers. Vitamin D supplementation reduces incidence of fractures, actually decreasing the number of falling [4,7]. Sarcopenia was initially defined as "disease of the elderly" and a degenerative consequence of ageing, but successively it can be also diagnosed at younger age [23].…”

“…Recently, elevated levels of PTH emerged as a possible risk factor for cardiovascular diseases since they could promote development of hypertension; in addition, hyperparathyroidism could cause heart hypercontractility and calcification of the myocardium. Vitamin D 3 could overcome these processes, promoting, for example, synthesis of anti-inflammatory cytokines [4]. Severe vitamin D 3 deficiency in humans is associated with cardiomyopathy [52], and in a number of large epidemiologic studies, the association of increased cardiovascular disease risk with low vitamin D 3 blood levels has been found [53].…”

“…Classical vitamin D-responsive tissues are bones, intestine, kidney, and parathyroid glands [1][2][3] and in this case, vitamin D induces skeletal effects. In addition many other organs respond to vitamin D, such as prostate, breast, immune cells, skeletal muscle, cardiac tissue, parathyroid glands, skin, and brain; all these organs express vitamin D receptor (VDR) and the enzyme 1α-hydroxylase and vitamin D exert extraskeletal effects [4]. Vitamin D exerts its activity through two mechanisms: the hormone signaling, in which the biologically active form reaches target cells through the bloodstream; and the autocrine/paracrine signaling, in which locally produced-vitamin D 3 affects the surrounding cells [5].…”

“…These include the significant impact of the vitamin D hormone on the cardiovascular system, central nervous system, endocrine system, and immune system as well as on cell differentiation and cell growth [4]. The term "vitamin D" refers to two different forms playing an important role in humans: vitamin D2 (ergocalciferol), which is made in some plants but largely in fungi [6], and vitamin D 3 (cholecalciferol), which is made by human skin when exposed to sunlight via the UV irradiation of 7-dehydrocholesterol [6].…”

What is the definition of "vitamin D deficiency" and who is considered "vitamin D deficient"? Urgent need for a national consensus

“…The spectrum of vitamin D health effects is quite wide, from bone and muscles (so-called calcemic effects) to a variety of non-calcemic effects including cardiovascular, insulin function, adipogenesis, obesity, immunity and mental status. Consequently, having an optimal vitamin D status has attracted a huge attention (4)(5)(6)(7)(8).…”