LAUSR

Since the discovery of vitamin D at the beginning of the 20th century that was later given to children to treat rickets, the implications of vitamin D to our health nowadays are so diverse. It has been shown that vitamin D role is not only in the classical effects of maintaining calcium and phosphate homeostasis in the blood and therefore the formation and maintenance of bones and teeth, but a host of newly substantiated non-classical effects which include the protection against common cancers, cognitive function, cardiovascular disease and its risk factors, immune system function and coordination of innate and adaptive immune responses, multiple sclerosis in humans and others. This mini review is intended to highlight the dangers of the silent hypo vitaminosis D syndrome and the importance of achieving adequate serum vitamin D levels. A crucial issue is to urgently commence optimizing and validating assay methods for vitamin D and its metabolites, as most of these are not reliable or have not been fully validated. Vitamin D and precursors are present only in some foods, and therefore supplements might be necessary especially for people who do not expose themselves sufficiently to sun light or in winter months for northern countries, though few researchers have expressed caution at the present time. Citation: Emad Al-Dujaili. “Vitamin D; Multi-Potent Hormone”. EC Nutrition 3.3 (2016): 656-660. There is now an overwhelming body of evidence for the multiplicity of regulatory and functional roles of vitamin D in the human body exerted through vitamin D receptors (VDR), which are present in many tissues including endothelial cells [1]. The implications of vitamin D to our health are diverse, not only the classical effects of maintaining calcium and phosphate homeostasis in the blood and the formation of bones and teeth, but the newly substantiated non-classical effects which include the protection against common cancers, cardiovascular disease, potent coordination of innate and adaptive immune responses and multiple sclerosis in humans [2]. VDR have a role in the conversion of 25(OH)D [3] to its active form 1,25-di(OH)D, and this has many functions including anti-proliferative effects on vascular smooth muscle, immune and renin-angiotensin-aldosterone systems modulation and stimulating release of inflammatory cytokines [3]. Therefore, the discovery of vitamin D receptors in many tissues has provided new insights into the broad functions of vitamin D and the adverse effects of its deficiency [4]. Several studies suggest that low serum vitamin D levels are associated with hypertension, glucose intolerance, dyslipidaemia, coronary artery calcification and thus, the onset of CVD. Vitamin D is needed for bone growth and remodelling, modulation of cell growth, neuromuscular and immune function and reduction of inflammation. Although the most well-known adverse effect of vitamin D deficiency involves the musculoskeletal system, an increasing body of evidence suggests that low levels of vitamin D may adversely affect the cardiovascular, immune, reproductive systems and others [5,31]. Vitamin D deficiency is highly prevalent worldwide. Low levels of serum vitamin D are present in as many as 30-50% of otherwise healthy adults [5]. Limited synthesis due to inadequate sun exposure, low intake of Vitamin D rich food, pigmented skin, indoor lifestyle and use of sun-screen are the main causes of low serum vitamin D levels, while a poor dietary habits and intake of vitamin D in food or supplement also contributes to the risk of deficiency. Hypovitaminosis D is very common in winter months in the UK; synthesis of vitamin D3 is almost impossible and the majority of the UK population might be vitamin D deficient [6]. Hypovitaminosis D is defined as a serum vitamin D level of < 40 nmol/L [7], though some researchers recommend a level of >75nmol/L to be adequate [8] and 80 to 100nmol/L Vitamin D; Multi-Potent Hormone