The effects of dietary selenium supplementation on inflammatory markers among patients with metabolic diseases: a systematic review and meta-analysis of randomized controlled trials.

PURPOSE: Selenium (Se) is a trace element having significant effects on human metabolism. Recent studies suggest that Se supplementation have a pivotal effect on the inflammatory markers. Therefore, the aim of this study was to assess the effect of Se supplementation on plasma inflammatory markers including C-reactive protein (CRP) and high-sensitivity C-reactive protein (hs-CRP) and nitric oxide (NO) as a stress oxidative index, among patients with metabolic diseases. METHODS: To assess the effects of Se on the inflammatory markers, following the PRISMA-P guidelines, we systematically searched ISI/WOS, PubMed/MEDLINE, and Scopus for studies that assessed the effect of Se supplementation on the inflammatory markers. Data extraction was performed by two independent investigators. Using the random effects or fixed-effects model depending on the results of heterogeneity tests was used to estimate the pooled standardized mean difference (SMD). Heterogeneity between studies was assessed using Cochran's Q test and I2 index. RESULTS: The initial search revealed 3,320 papers. After screening process and considering inclusion criteria, 7 publications were eligible for inclusion in the meta-analysis. The meta-analysis results showed that Se supplementation did not significantly affect CRP and hs-CRP concentrations (mean difference (MD) = -0.15; 95% CI: -0.55- 0.23; P = 0.43). Subgroup analysis of CRP type showed that Se supplementation significantly decreased hs-CRP level (pooled SMD = -0.44; 95% CI: -0.67-0.21). Moreover, no significant change was observed in NO level by continuing to take Se supplementation, (pooled SMD: 0.003, 95%CI: -0.26, 0.26). CONCLUSIONS: This study revealed that Se supplementation would have desirable effects on cardio-metabolic indicators through affecting the levels of inflammatory markers. Given the importance of concerns, more attention should be given to more prospective studies with longer follow-up.

Food Insecurity and Dietary Intake Among Elderly Population: A Systematic Review.

BACKGROUND: This review seeks to determine the relationship between food insecurity among elderly people over the past decades and nutrient deficiency, which is rather unclear. We aim to systematically review the relationship between food insecurity and dietary intake among elderly population. METHODS: In this systematic review, we systematically searched the international databases including PubMed, Web of Sciences, and Scopus for scientifically related papers which have been published up until January 2018. For a more refined search, we used the Medical Subject Headings (MeSH) terms and Emtree. In terms of search protocol, no restrictions were placed on time and language. Two independent reviewers conducted the data refining processes. Validated form (PRISMA) was used to conduct quality assessment and data extraction. RESULTS: Eight cross sectional studies have been included in this review. Two of the studies were conducted in Asia and the remaining six studies were largely based in the United States and Canada. Food insecurity was associated with low levels of vitamin and mineral intakes such as vitamins E, A, B, and D and also zinc, calcium, magnesium, and iron. Most studies also reported insufficient energy, and micro and macronutrients intake among elderly people. CONCLUSIONS: The findings of this review evidence a considerable amount of food insecurity and nutrient deficiency, including vitamins E, C, D, B 2, and B 12 and zinc, phosphorus, and calcium among elderly population. These findings could be used as reliable evidence by policy makers and future complementary analyses.

Effect of glutamine supplementation on cardiometabolic risk factors and inflammatory markers: a systematic review and meta-analysis.

BACKGROUND: Evidence exists that glutamine plays multiple roles in glucose metabolism, insulin sensitivity, and anti-inflammatory effects. This systematic review and meta-analysis of controlled trials aimed to assess the effect of glutamine supplementation on cardio-metabolic risk factors and inflammatory markers. METHODS: The processes of systematic reviews and meta-analyses were performed according to the PRISMA checklist. PubMed, Web of Sciences, Cochrane library, and Scopus databases were search for relevant studies without time or language restrictions up to December 30, 2020. All randomized clinical trials which assessed the effect of glutamine supplementation on "glycemic indices", "level of triglyceride, "and "inflammatory markers" were included in the study. The effect of glutamine supplementation on cardio-metabolic risk factors and inflammatory markers was assessed using a standardized mean difference (SMD) and 95% confidence interval (CI). Heterogeneity between among studies was assessed using Cochran Q-statistic and I-square. Random/fixed-effects meta-analysis method was used to estimate the pooled SMD. The risk of bias for the included trials was evaluated using the Cochrane quality assessment tool. RESULTS: In total, 12 studies that assessed the effect of glutamine supplementation on cardio-metabolic risk factors were included in the study. Meta-analysis showed that glutamine supplementation significantly decreased significantly serum levels of FPG [SMD: - 0.73, 95% CI - 1.35, - 0.11, I2: 84.1%] and CRP [SMD: - 0.58, 95% CI - 0.1, - 0.17, I2: 0%]. The effect of glutamine supplementation on other cardiometabolic risk factors was not statistically significant (P > 0.05). CONCLUSION: Our findings showed that glutamine supplementation might have a positive effect on FPG and CRP; both of which are crucial as cardio-metabolic risk factors. However, supplementation had no significant effect on other cardio-metabolic risk factors.

Correction to: Effect of selenium supplementation on antioxidant markers: a systematic review and meta-analysis of randomized controlled trials.

The original version of this article, published on 10 December 2019 contained a mistake.

Lifestyle interventions in the maritime settings: a systematic review.

BACKGROUND: Evidence on workplace health promotion interventions at sea is scattered and includes different methodological approaches. The continued focus on lifestyle and health promotion on land-based industries makes it pertinent to evaluate available data from maritime settings to gain systematic knowledge on the field. METHODS: In this systematic review, we systematically searched PubMed and NLM Gateway (for MEDLINE), Institute of Scientific Information/Web of Science (ISI/WOS), and SCOPUS up to January 2019 using standard keywords including lifestyle interventions in the maritime setting. Two independent reviewers assessed papers and extracted the data. The quality of included studies was assessed using the Cochrane Risk of Bias tool. Due to significant heterogeneity between studies, the effectiveness of interventions was presented as a qualitative synthesis. RESULTS: After the initial search and refinement based on a total of 4432 records, ten articles met eligibility criteria and were included in the final review. Six studies originated from US maritime settings, 3 studies were conducted on Danish seafarers and one study came from Finland. The main focus of 6 studies was educational interventions including stress management, healthy eating, anti-smoking and anti-drinking sessions, sexual behavior program, and advice about preventive strategies. Four studies described the implementation of interventions, including micro-nutrient supplementation, physical activity, and pharmacotherapy. Follow-up assessments occurred over a time period ranging from 80 days to 2 years. Three studies found a positive though limited effect of structural and/or education interventions in maritime settings. The quality of all included studies was modest. CONCLUSION: Results of this systematic review show that a limited number of studies of lifestyle interventions in the maritime setting exist and that the quality of them is generally modest. Also, most of the interventions identified have failed to demonstrate substantial health benefits for seafarers. Systematic review registration number in PROSPERO: CRD42019134533.

Effects of Zinc Supplementation on Cardiometabolic Risk Factors: a Systematic Review and Meta-analysis of Randomized Controlled Trials.

The prevalence of cardiometabolic risk factors has been increasing worldwide. The results of reported studies on the effects of zinc supplementation on cardiometabolic risk factors are unequivocal. This systematic review and meta-analysis of randomized controlled trials was conducted to evaluate the effects of zinc supplementation on cardiometabolic risk factors. A systematic search was conducted through international databases (PubMed/Medline, Institute of Scientific Information, and Scopus) until December 2018 to include all randomized controlled trials (RCT), quasi-RCT, and controlled clinical trials which assessed the effect of zinc supplementation on cardiometabolic risk factors including lipid profile, glycemic indices, blood pressure, and anthropometric indices. Random- or fixed-effects meta-analysis method was used to estimate the standardized mean difference (SMD) and 95% confidence interval (CI). A total of 20 studies were included in the meta-analysis, which included a total of 1141 participants in the intervention group. Meta-analysis showed that zinc supplementation significantly decreased plasma levels of triglyceride (SMD - 0.66, 95% CI - 1.27, - 0.06), very-low-density lipoprotein (SMD - 1.59, 95% CI - 2.86, - 0.31), and total cholesterol (SMD - 0.65, 95% CI - 1.15, - 0.15). Similarly, zinc supplementation significantly decreased fasting blood glucose (SMD - 0.52, 95% CI - 0.96, - 0.07) and HbA1c (SMD - 0.64, 95% CI - 1.27, - 0.02). The effects of zinc supplementation on blood pressure and anthropometric indices were not statistically significant (P > 0.05). Zinc supplements had beneficial effects on glycemic indices and lipid profile. Thus, it appeared that zinc supplementation might be associated with a decrease in cardiometabolic risk factors contributing to a reduction in risk of atherosclerosis.

Effect of selenium supplementation on antioxidant markers: a systematic review and meta-analysis of randomized controlled trials.

AIM: The aim of this study is the systematic review and meta-analysis of controlled trial studies to assess the antioxidant effects of selenium (Se) supplementation. METHODS: The systematic review and meta-analysis were performed according to the previously published protocol. The PubMed, Web of Sciences, and Scopus databases were meticulously searched for relevant data, without time or language restriction, up to June 1, 2017. All clinical trials which assessed the effect of Se supplementation on antioxidant markers, including oxidative stress index (OSI), antioxidant potency composite (APC) index, plasma malonaldehyde (MDA), total antioxidant capacity (TAC), antioxidant enzymes (superoxide dismutase (SOD), glutathione peroxidase (GPX), catalase (CAT)), and total antioxidant plasma (TAP), were included. The effect of Se supplementation on antioxidant markers was assessed using standardized mean difference (SMD) and 95% confidence interval (CI). The random-effect meta-analysis method was used to estimate the pooled SMD. RESULTS: In total, 13 studies which assessed the effect of Se supplementation on antioxidant markers were included. The random-effect meta-analysis method showed that Se supplementation significantly increased GPX (SMD = 0.54; 95% CI = 0.21-0.87) and TAC (SMD = 0.39, 95% CI = 0.13, 0.66) levels and decreased MDA levels (SMD = - 0.54, 95% CI = - 0.78, - 0.30). The effect of Se supplementation on other antioxidant markers was not statistically significant (P > 0.05). CONCLUSION: The findings showed that Se supplementation might reduce oxidative stress by increasing TAC and GPX levels and decreasing serum MDA, both of which are crucial factors for reduction of oxidative stress.

Effects of Selenium Supplementation on Cardiometabolic Risk Factors, Inflammatory, and Antioxidant Markers: A Systematic Review and Meta-analysis Protocol.

BACKGROUND: Selenium (Se) is considered as an antioxidant trace element involved in key activities in human metabolism. Recent investigations indicate that Se plays a pivotal role in human health. Se supplementation considered as an intervention is both cost-effective and simple-to-use that may play an important role in the prevention of cardiometabolic risk factors (CRFs), inflammatory, and antioxidant markers. METHODS: This paper is a protocol study on systematic review of probable effects of Se supplementation on CRFs, inflammatory, and antioxidant markers. The aim was to achieve three international databases available related to the current publications including, PubMed, ISI/WOS, and Scopus. We attempted to search for randomized clinical trials (RCT) and cross-over trials pertaining to human subjects without any restriction on language and time. In addition, there was no limitation on the age of participants. For RCTs were included all studies in different target groups comprising diabetic patients, patients with polycystic ovarian syndrome, obese subjects, or even healthy controls. To investigate the effect of Se, we included all studies which Se is used either as single therapy or as combination therapy. All studies associated with articles and meta-analyses would be evaluated to review their references. CONCLUSIONS: The current study contained numerous outcomes. The result of this study can be led to make reliable scientific evidence on the probable effects of Se supplementation on CRFs, inflammatory factors, and antioxidant factors. In addition to these findings, other technical documents developed for a systematic review can be used for future studies.

Effect of selenium supplementation on glycemic indices: a meta-analysis of randomized controlled trials.

PURPOSE: The association between selenium supplementation and glycemic indices seems to be a controversial issue. This systematic review and meta-analysis was conducted to evaluate the effect of selenium supplementation on glycemic indices. METHODS: We systematically searched PubMed/MEDLINE, ISI/WOS, and Scopus (from their commencements up to Jan 2016) for relevant studies examining the association between intake of selenium and glycemic indices. The data were extracted from relevant qualified studies and estimated using the random-effect or pooled model and standardized mean difference (SMD) with 95% confidence interval (CI). RESULTS: Twelve articles published between 2004 and 2016 were included. In all the studies, the participants were randomly assigned to an intervention group (n = 757) or a control group(n = 684). All the studies were double blind, placebo controlled trials. Selenium supplementation resulted in a significant decrease in homeostasis model of assessment-estimated ß-cell function (HOMA-B) (SMD: -0.63; 95%CI: -0.89 to -0.38) and a significant increase in quantitative insulin sensitivity check index (QUICKI) (SMD: by 0.74; 95%CI: 0.49 to 0.1) as compared with the controls. There were no statistically significant improvements in glycemic indices, such as fasting plasma glucose (FPG), insulin, homeostasis model of assessment-estimated insulin resistance (HOMA-IR), Hemoglobin A1c (HbA1c) and adiponectin. CONCLUSION: This meta-analysis indicated that selenium supplementation significantly decreased HOMA-B and increased QUICKI score. There was no statistically significant improvement in FPG, insulin, HOMA-IR, HbA1c and adiponectin indices following selenium supplementation.

Effect of Selenium Supplementation on Lipid Profile: A Systematic Review and Meta-Analysis.

Selenium is an essential mineral that plays a key role in plenty of major metabolic processes. A growing body of literature has shown that selenium deficiency leads to an increase in plasma TC and TG levels. This study explores the effect of selenium supplementation on serum level of lipid profile [total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL), very low density lipoprotein (VLDL)]. We systematically searched PubMed/MEDLINE, ISI/WOS, and Scopus (from their commencements to Jan 2016) to identify the papers investigating the association between the intake of selenium and lipid profile. Data extracted from the relevant studies were screened. The pooled standardized mean difference was estimated using the random or fixed effects model. Heterogeneity among the studies was assessed using Q-test. Of the potentially relevant articles screened, 11 articles including 1221 participants were included in this meta-analysis. Results of meta-analysis showed that intake of selenium resulted in a statistically significant improvement in TC, [(SMD): -0.13, 95% CI: (-0.24, -0.02)], TG [(SMD): -0.19, 95% CI: (-0.38, -0.01)] and VLDL [(SMD): -0.34, 95% CI: (-0.63, -0.05)]. The selenium supplementation did not significantly improve lipid profile such as LDL [(SMD): -0.08, 95% CI: (-0.036, 0.19)], HDL [(SMD): 0.01, 95% CI: (-0.164, 0.18)], HDL/TC ratio [(SMD): 0.025, 95% CI: (-0.11, 0.16)], non-HDL-C [(SMD): 0.018, 95% CI: (-0.13, 0.16)]. This meta-analysis suggests that the effect of selenium supplementation on the serum levels of TG and VLDL is marginally significant. However, the supplementation has no effect on other serum lipids. Moreover, the study shows that the effect of selenium supplementation on lipid profile is negative.