Thesis (MNutr)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The possible advantages of vitamin D supplementation on various cardiometabolic conditions have been examined over the past few years. Vitamin D supplementation has possibly shown effects on each of the individual components of the metabolic syndrome i.e.: obesity, hypertension, dyslipidaemia and glucose intolerance. The aim of this systematic review was to ascertain whether or not vitamin D supplementation has any effect on any of the components of the metabolic syndrome. We searched the (Cochrane Central Register of Controlled Trails (Central), Medline, Science direct, ISI Web of knowledge and Scopus during 2010 (repeated search in 2012). We found four randomized controlled trials that met our inclusion and exclusion criteria. Three hundred and seventy three patients were included in these four randomized controlled trails comparing vitamin D supplementation with placebo. Duration of treatment was a minimum of 4 weeks, through to a maximum of on-year. The different trials looked at various components of the metabolic syndrome as outcomes. The results were not consistent amongst the trials and the results could not be combined in a meta-analysis due to heterogeneity in study design and outcomes measured. The current systematic review highlights the shortcomings in the published data and we recommend further trials be undertaken before vitamin D supplementation can be recommended as beneficial for patients with the metabolic syndrome. / AFRIKAANSE OPSOMMING: Die moontlike voordele van vitamien D-aanvullings op verskillende kardiometaboliese toestande is oor die afgelope paar jaar ondersoek. Daar is aangetoon dat vitamien Daanvullings uitwerkings het op elk van die individuele komponente van die metaboliese sindroom naamlik vetsug, hipertensie, dislipidemie en glukose-intoleransie. Die doel van hierdie sistematiese oorsig was om vas te stel of vitamien D-aanvullings enige uitwerking het op enige van die komponente van die metaboliese sindroom of nie. Ons het gedurende 2010 soektogte uitgevoer op die Cochrane Sentrale register van gekontroleerde proewe (Central), Medline, Science Direct, ISI Web of Knowledge en Scopus (soektog is in 2012 herhaal). Ons het vier verewekansigde gekontroleerde proewe wat aan ons insluiting- en uitsluitingskriteria voldoen het, opgespoor. Driehonderd drie en sewentig pasiënte is by die vier proewe ingesluit. Al vier proewe het vitamien D-aanvullings met plasebo vergelyk. Die duur van behandeling het van 4 weke tot een jaar gestrek. Die verskillende proewe het gekyk na verskillende komponente van die metaboliese sindroom as uitkomste. Die resultate van die onderskeie proewe was nie konsekwent nie. Die huidige sistematiese oorsig belig die tekortkominge in die gepubliseerde data en ons beveel aan dat verdere proewe onderneem word om vas te stel of dit nuttig is om vitamien D aanvullings vir pasiënte met die metaboliese sindroom aan te beveel, en of dit dalk skadelik kan wees.

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published_or_final_version / Community Medicine / Master / Master of Public Health

Vitamin D insufficiency/deficiency is widespread in asthma, and epidemiological studies point to an association between low serum 25-hydroxyvitamin D level and poor asthma control and increased severity. In humans. Vitamin D is principally derived from sunlight induced cutaneous conversion of 7-dehydrocholesterol to vitamin D and oral supplementation. We sought to determine if established and chronic-persistent adult asthma patients from a South-Florida pulmonary patient population, with abundant sunshine availability and oral vitamin D supplementation exhibit vitamin D insufficiency/deficiency. A trend to vitamin D insufficiency was observed in approximately 65% of both adult asthma patients and apparently healthy (non-asthmatic) volunteers. . The transcription factors required for Th9 conversion, PU.1 and IRF-4, were down-regulated by vitamin D. The generation of Th9 cells was inhibited equally by vitamin D and dexamethasone when used alone, but the effect was additive when both steroids were used in combination. Our studies using non-specifically stimulated cells were extended by analyzing the effect of vitamin D on allergen specific stimulation. The response of CD4+ T cells obtained from the blood of house dust mite positive asthmatics was studied. House dust mite allergen elicited a classical Th2 phenotype response (IL-4, IL-5, IL-9, and IL-13 cytokine profile) and vitamin D effectively inhibited those key Th2 cytokines. We conclude that vitamin D appears to be of significant clinical benefit in our cohort of patients, i.e., established chronic adult human asthma, by down-regulating key immune cells including Th9, Th17, and Th2 involved in this disorder. / by Amjad Munim. / Thesis (Ph.D.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.