Vitamin D in the light of current knowledge

Abstract

Vitamin D, i.e. 1,25(OH) 2D, is an essential factor, not only of homeostasis of calcium and phosphorus, but also of cell proliferation, differentiation and apoptosis, immune and hormonal regulation, as well as other body processes. Thus, its optimal presence in the body is of exceptional significance for health, both of children, as well as adults and elderly persons. Today, it is known that the lack of vitamin D, besides having negative effects on the skeleton and teeth, also contributes to the development of various malignancies, primarily of the large bowel, prostate and breasts, as well as of autoimmune and allergic diseases, diabetes mellitus type II, arterial hypertension and others. Considered from the biological aspect, physiological requirements in vitamin D are achieved by cutaneous synthesis from 7-dehydrocholesterol during sun exposure, while, except rarely, it is very scarce in food. Having in mind extensive evidence that sun exposure presents a high risk for the development of skin malignancies, primarily melanoma, it is clear that humans are deprived of the natural and basic source of vitamin D. In accordance, as well as based on numerous epidemiological studies showing the increase of diseases, in the basis of which vitamin D deficiency plays the important role, next led to the recommended dietary allowance of vitamin D, regardless of age. According to current attitudes, it is recommended that the daily dietary allowances of vitamin D. i.e. the quantity of oral intake that would safely cover the optimal body requirements should be 400 IU for ages 0-18 years, 600 IU for ages 19-70 years and 800 IU for persons aged over 70 years.Vitamin D, odnosno 1,25(OH)2D, jeste esencijalni cinilac ne samo homeostaze kalcijuma i fosfora, nego i proliferacije, diferencijacije i apoptoze celija, imunske i hormonske regulacije i drugih procesa u organizmu. Otuda je njegov optimalan nivo u telu coveka veoma znacajan za zdravlje, kako dece, tako i odraslih i starih ljudi. Nedostatak vitamina D, pored losih posledica na skelet i zube, doprinosi pojavi razlicitih maligniteta, pre svega debelog creva, prostate i dojke, zatim autoimunoloskih i alergijskih oboljenja, dijabetesa tip II, arterijske hipertenzije i dr. Posmatrano sa bioloskog aspekta, fizioloske potrebe za vitaminom D ostvaruju se kutanom sintezom iz 7-dehidroholesterola tokom suncanja, dok je hrana, sem retkih izuzetka, veoma oskudna u njemu. Imajuci u vidu brojne dokaze da je izlaganje suncu veliki rizik za pojavu maligniteta koze (prevashodno melanoma), jasno je da je covek ostao bez svog prirodnog i osnovnog izvora vitamina D. U skladu s tim, kao i na osnovu raznih epidemioloskih istrazivanja koja ukazuju na povecanje broja oboljenja u cijoj osnovi bitno ucesce ima nedostatak vitamina D, usledile su preporuke da se on, bez obzira na zivotno doba, mora unositi. Prema savremenim stavovima, preporucena dnevna doza vitamina D, tj. kolicina koja oralno uneta zadovoljava optimalne potrebe organizma, jeste 400 IJ u uzrastu do 18 godina, 600 IJ u periodu izmedju 19. i 70. godine, odnosno 800 IJ posle 70. godine.