Nutrient Supplementation Policies Of Different Countries And A Meta-analysis About The Effect Of Vitamin D Supplementation On Blood Pressure

Dietary supplements are a preferred choice by majority of people since all required nutrients by the body cannot be met in our diet sometimes.In areas that have long winters and a limited exposure to sunlight chances are that they often use supplementation with vitamin D.Emphasis however,has to be on lookout for the required amount of intake according to the different guidelines in different countries.With controversies stemming from cardiovascular risk,diabetes,kidney diseases,cancers and usage of dietary supplementation it is worthwhile mentioning that with available information on government websites and regulatory authority websites,people will take responsibility in purchasing the right choice of nutrient supplements tailored to why they want them.Every country has access to dietary supplements though some may not be able to transact or buy specific types on grounds of what is or not considered a nutrient supplement a particular country.Part I:Nutrient supplementation policies in different countriesThere is considerable evidence that dietary supplements alleviate symptoms,improve health status,reclaim or delay the risk of onset of morbidity in different population groups such as unborn babies,postmenopausal women and pregnant women.However,concerns have come up concerning dosage,safety and regulation in different parts of the world some stipulating whether consumption is significant or not.Europe and America demonstrate that they have had the good time of dietary supplementation up to when the act was revised and the food and drug administration was no longer putting stringent regulations on nutrient supplement manufacturers such as chemical analysis,identification and quantification of the ingredients used.It is mandatory for the development of strict and authentic regulatory environment that encourages approval of various forms of nutritional supplements including botanicals,metabolites and drugs is emphasized.It is predictable that for a bright future in nutrition and stability of supplementation use to the diet it will be appreciated in medical practice.However,this will be when governments invest more in their policy formulation and ensure efficacy and safety of these supplements to the general population.Part Ⅱ:A Meta-analysis about the effect of vitamin D supplementation on blood pressure.Objective:This meta-analysis seeks to determine the effects of vitamin D supplementation on blood pressure.Methods:A systematic search for randomized controlled trials of vitamin D was undertaken,published studies were identified from PubMed and Web of Science(July 2016-April 2017).The keywords and Medical Subject Headings(MeSH)for the population and the intervention were:"vitamin D","cholecalciferol","randomized","controlled trial","clinical trial" cardiovascular outcome,coronary artery disease;hypertension,myocardial infarction,heart failure and stroke of which some were adopted as appropriate for Web of Science as well.PubMed and Web of Science were searched for studies examining the effect vitamin D supplementation on various cardiovascular markers.Data were analyzed using weighted mean difference(effect size)and pooled mean difference for the differences in both systolic and diastolic blood pressures.Random effect models were used for the pooled estimates with 95%confidence intervals(CI)to analyze the effects of vitamin D supplementation on blood pressure because heterogeneity statistic 12 were 65.5%and 64.5%for systolic and diastolic blood pressure respectively which were considered moderate.Studies were small with varying methodological quality.Quality of the clinical trials was assessed using the Jadad score and reporting on the following items were of special interest;randomization,double blinding,withdrawal and dropouts was used for quality evaluation of the trials used in the study.Studies used had a score range between 4 and 5 which rendered them of good quality whereby 0 score meant bad and 5 best.Sensitivity analysis was used to detect the stability of the results of the meta-analysis,and the potential publication bias was analyzed using Begg funnel as they indicated no evidence of possible publication bias.Results:Initial searches yielded 98 articles.Of these original results,8 met specific selection criteria of which 6 randomized controlled trials with a total of 1415 participants were assessed for the effect of vitamin D supplementation with placebo on blood pressure and were included in the meta-analysis.Participants included healthy individuals,elderly people and those with hypertension and diabetes.Data concerning author’s name,year of publication,study design,study duration,geographical location of population,and participant characteristics interventions was included.Majority of the clinical trials were conducted in high income countries especially in Europe,United States and one in Korea,total number of study duration of study was between 2 months and 1 year,mean age where stated ranged between 36 and 77 years.The vitamin D supplementation interventions showed a higher mean difference in change of blood pressure readings(mean difference =-0.08,95%CI;0.30 to 0.14,P=0.013 and I2 65.5%for Systolic Blood Pressure.Mean difference=0.00,95%Cl;-0.22 to 0.22,P=0.015 and I2= 64.6%for Diastolic blood pressure).Conclusions:Studies showed no significant reduction in blood pressure as a result of vitamin D supplementation in both the experimental and placebo groups.From this meta-analysis vitamin D has a potentially significant role in improving blood pressure levels although the results were not statistically significant.It can therefore be considered appropriate and safe for hypertensive patients and the general population much as the change was not statistically significant.However,RCT studies with larger sample sizes and for a longer duration need to confirm this in healthy individuals.