The effect of high-polyphenol extra virgin olive oil on cardiovascular risk factors: A systematic review and meta-analysis

Abstract

The polyphenol fraction of extra-virgin olive oil may be partly responsible for its cardioprotective effects. The aim of this systematic review and meta-analysis was to evaluate the effect of high versus low polyphenol olive oil on cardiovascular disease (CVD) risk factors in clinical trials. In accordance with PRISMA guidelines, CINAHL, PubMed, Embase and Cochrane databases were systematically searched for relevant studies. Randomized controlled trials that investigated markers of CVD risk (e.g. outcomes related to cholesterol, inflammation, oxidative stress) were included. Risk of bias was assessed using the Jadad scale. A meta-analysis was conducted using clinical trial data with available CVD risk outcomes. Twenty-six studies were included. Compared to low polyphenol olive oil, high polyphenol olive oil significantly improved measures of malondialdehyde (MD: ?0.07µmol/L [95%CI: ?0.12, ?0.02µmol/L]; I²: 88%; p?=?0.004), oxidized LDL (SMD: ?0.44 [95%CI: ?0.78, ?0.10µmol/L]; I²: 41%; P?=?0.01), total cholesterol (MD 4.5 mg/dL [95%CI: ?6.54, ?2.39 mg/dL]; p<0.0001) and HDL cholesterol (MD 2.37 mg/dL [95%CI: 0.41, 5.04 mg/dL]; p?=?0.02). Subgroup analyses and individual studies reported additional improvements in inflammatory markers and blood pressure. Most studies were rated as having low-to-moderate risk of bias. High polyphenol oils confer some CVD-risk reduction benefits; however, further studies with longer duration and in non-Mediterranean populations are required.     

Lipid-modifying activity of curcuminoids: A systematic review and meta-analysis of randomized controlled trials

Objective: The aim of this systematic review and meta-analysis was to determine and clarify the impact of curcuminoids on serum lipid levels. Methods: Randomized controlled trials (RCTs) investigating the effects of curcuminoids on plasma lipids were searched in PubMed-Medline, Scopus, Web of Science databases (from inception to April 3^rd, 2017). A random-effects model and generic inverse variance method were used for quantitative data synthesis. Sensitivity analysis was conducted using the leave-one-out method. A weighted random-effects meta-regression was performed to evaluate the impact of potential confounders on lipid concentrations. Results: A meta-analysis of 20 RCTs with 1427 participants suggested a significant decrease in plasma concentrations of triglycerides (WMD: ?21.36 mg/dL, 95% CI: ?32.18, ?10.53, p < 0.001), and an elevation in plasma HDL-C levels (WMD: 1.42 mg/dL, 95% CI: 0.03, 2.81, p = 0.046), while plasma levels of LDL-C (WMD: ?5.82 mg/dL, 95% CI: ?15.80, 4.16, p = 0.253) and total cholesterol (WMD: ?9.57 mg/dL, 95% CI: ?20.89, 1.75, p = 0.098) were not altered. The effects of curcuminoids on lipids were not found to be dependent on the duration of supplementation. Conclusion: This meta-analysis has shown that curcuminoid therapy significantly reduces plasma triglycerides and increases HDL-C levels.     

Effects of quercetin supplementation on lipid profile: A systematic review and meta-analysis of randomized controlled trials

Background: In spite of promising experimental findings, randomized controlled trials (RCTs) have yielded mixed results on the impact of quercetin supplementation on plasma lipid levels.

Aim: The present study aimed to quantify the effects of quercetin on plasma lipids using a meta-analysis of RCTs.

Methods: A systematic literature search of Medline was conducted for RCTs that investigated the efficacy of quercetin supplementation on plasma lipids comprising total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides. Weighted mean differences (WMDs) and 95% confidence intervals (CIs) were calculated for net changes in lipid concentrations using a random-effects model. Meta-regression analysis was conducted to assess the effect of quercetin dose and duration of supplementation as moderators on the calculated effect measures.

Results: Five RCTs totaling 442 subjects (221 in the quercetin and 221 in the control group) fulfilled the eligibility criteria and selected for analyses. Combined estimate of effect size for the impact of quercetin on plasma LDL-C (WMD: 1.43 mg/dL, 95% CI: ?0.92–3.78, p = 0.23), HDL-C (WMD: 0.26 mg/dL, 95% CI: ?0.74–1.25, p = 0.61) and triglycerides (WMD: ?9.42 mg/dL, 95% CI: ?27.80–8.96, p = 0.32) was not statistically significant. However, a borderline significant but clinically non-relevant increase in total cholesterol was observed (WMD: 3.13 mg/dL, 95% CI: ?0.01–6.27, p = 0.05). When the analysis was confined to the subgroups of studies with quercetin doses ≥500 mg/day and follow-up of ≥ 4 weeks, a significant increase in total cholesterol (WMD: 3.57 mg/dL, 95% CI: 0.21–6.92, p = 0.04) and a decline in triglycerides (WMD: ?24.54 mg/dL, 95% CI: ?33.09 to ?15.99, p < 0.00001) was observed, but LDL-C and HDL-C concentrations remained unchanged (p > 0.05). Changes in plasma triglycerides, but not other indices of lipid profile, were significantly associated with quercetin dose (slope: ?0.057; 95% CI: ?0.103 to ?0.010; p = 0.02) and duration of supplementation (slope: ?5.314; 95% CI: ?9.482 to ?1.147; p = 0.01).

Conclusion: Available evidence from RCTs does not suggest any clinically relevant effect of quercetin supplementation on plasma lipids, apart from a significant reduction of triglycerides at doses above 50 mg/day.     

The effects of supplementation with conjugated linoleic acid on anthropometric indices and body composition in overweight and obese subjects: A systematic review and meta-analysis

Abstract

Clinical trials have indicated conflicting results on the effects of conjugated linoleic acid (CLA) on obesity. The present study aimed to systematically review controlled clinical trials examining the effects of CLA on anthropometric indices and body composition in overweight and obese subjects. Pubmed, Scopus, Web of science, and Cochrane databases were searched between 2000 and December 2017 with no language restriction. Placebo-controlled clinical trials that reported anthropometric indices and body composition in overweight and obese subjects were included. Random-effect model was used to pool the effect estimates. Of 4032 publications, 13 trials were included for the meta-analysis. Pooled effect sizes indicated that CLA significantly reduced body weight (WMD: ?0.52 kg, 95% CI: ?0.83, ?0.21; I²: 48.0%, p?=?0.01), BMI (WMD: ?0.23 kg/m², 95% CI: ?0.39,???0.06; I²: 64.7%, p?=?0.0001), FM (WMD: ?0.61 kg, 95% CI: ?0.98, ?0.24; I²: 53.8%, p?=?0.01) and increased LBM (WMD: 0.19 kg, 95% CI: 0.04, 0.34; I²: 81.4%, p?=?0.0001) compared to the placebo group. However, the effects of CLA on WC (WMD: 0.05 cm, 95% CI: ?0.01, 0.1; I²: 0%, p?=?0.93) was not significant. Additionally, its impact on body weight in subjects older than 44 year (WMD: ?1.05 kg, 95% CI: ?1.75, ?0.35; I²: 57.0%, p?=?0.01), with longer duration (more than 12 weeks) (WMD: ?1.29 kg, 95% CI: ?2.29, ?0.29; I²: 70.3%, p?=?0.003) and dosage more than 3.4 g/day (WMD: ?0.77 kg, 95% CI: ?1.28, ?0.25; I²: 62.7%, p?=?0.004) were greater than comparative groups. Supplementation with CLA can slightly reduce body weight and FM and increase LBM in overweight and obese subjects. However, its efficacy was not clinically considerable. Further studies with high methodological quality are needed to shed light on the effects of CLA on anthropometric indices in overweight and obese subjects.     

The effects of psyllium supplementation on body weight,body mass index and waist circumference in adults: A systematic review and dose-response meta-analysis of randomized controlled trials

Abstract

Background: Previous studies reported inconsistent findings regarding the effects of psyllium supplementation on obesity measures. This systematic review and meta-analysis was performed to summarize data from available randomized clinical trials (RCTs) on the effect of psyllium supplementation on body weight, body mass index (BMI), and waist circumference (WC) in adults.

Methods: PubMed, SCOPUS, Cochrane Library, and Google Scholar were searched to identify relevant articles up to August 2018. The effect sizes were presented as weighted mean difference (WMD) and 95% confidence intervals (CI) by using random effects model. To detect dose-response relationships, we used fractional polynomial modeling.

Results: A total of 22 RCTs were included. Meta-analysis did not find any significant effect of psyllium supplementation on body weight (MD: ?0.28?kg, 95% CI: ?0.78, 0.21, p?=?0.268), BMI (MD: ?0.19?kg/m², 95% CI: ?0.55, 0.15, p?=?0.27) and WC (MD: ?1.2?cm, 95% CI: ?2.6, 0.2, p?=?0.09). Subgroup analysis showed that psyllium dosage, kind of psyllium administration, duration of trial, study design, sample size, and gender were potential sources of heterogeneity. Moreover, there was nonlinear association between duration of psyllium consumption, BMI and WC.

Conclusion: Psyllium supplementation does not reduce body weight, BMI, and WC significantly.     

The effects of chitosan supplementation on body weight and body composition: a systematic review and meta-analysis of randomized controlled trials

Abstract

Although several clinical trials studied the efficacy of chitosan on weight loss, controversial results have been found. Herein, we evaluated randomized controlled trials (RCTs) of chitosan consumption in adult participants on body weight and body composition through a meta-analysis with trial sequential analysis (TSA). We searched EMBASE, MEDLINE, Web of Science, and CENTRAL databases. The primary body composition indices including body weight, body mass index (BMI), waist circumference, body fat, and hip circumference were extracted. The quality of included articles was assessed according to the Cochrane risk of bias tool. Data were pooled using the random-effects models and calculated as weighted mean difference (WMD) with 95% confidence intervals (CI). Heterogeneity investigated using I² statistics. TSA, subgroup analyses, sensitivity analysis, meta-regression and publication bias were also evaluated. Overall, 15 eligible trials (18 treatment arms) with 1130 subjects were included. The pooled analyses revealed a significant reduction in body weight (WMD, ?0.89?kg; 95% CI, ?1.41 to ?0.38; P?=?0.0006), BMI (WMD, ?0.39?kg/m²; 95% CI, ?0.64 to ?0.14; P?=?0.002) and body fat (WMD, ?0.69%; 95% CI, ?1.02 to ?0.35; P?=?0.0001) receiving chitosan supplementation. Subgroup analyses also showed that consuming chitosan in dose (>2.4?g/d), shorter-term (<12?weeks), studies with parallel design and studies including participants with obese or overweight had positive effects on body composition. TSA provided conclusive evidence for the benefit of chitosan supplementation. Our findings provided evidence that chitosan consumption might be a useful adjunctive pharmacological therapeutic tool for body weight management particularly in overweight/obese participants. Further well-constructed clinical trials that target body weight and body composition as their primary outcomes are needed.     

Comparison of blood lipid-lowering effects of olive oil and other plant oils: A systematic review and meta‐analysis of 27 randomized placebo‐controlled clinical trials

Objective: We aim to report a systematic review and meta-analysis of randomized controlled trials (RCTs) on effects of olive oil consumption compared with other plant oils on blood lipids.

Methods: PubMed, web of science, Scopus, ProQuest, and Embase were systematically searched until September 2017, with no age, language and design restrictions. Weighed mean difference (WMD) and 95% confidence interval (CI) were expressed as effect size. Sensitivity analyses and pre specified subgroup was conducted to evaluate potential heterogeneity. Meta-regression analyses were performed to investigate association between blood lipid-lowering effects of olive oil and duration of treatment.

Results: Twenty-seven trials, comprising 1089 participants met the eligibility criteria. Results of this study showed that compared to other plant oils, high-density lipoprotein level increased significantly more for OO (1.37 mg/dl: 95% CI: 0.4, 2.36). Also OO consumption reduced total cholesterol (TC) (6.27 mg/dl, 95% CI: 2.8, 10.6), Low-density lipoprotein (LDL-c) (4.2 mg/dl, 95% CI: 1.4, 7.01), and triglyceride (TG) (4.31 mg/dl, 95% CI: 0.5, 8.12) significantly less than other plant oils. There were no significant effects on Apo lipoprotein A1 and Apo lipoprotein B.

Conclusion: This meta-analysis suggested that OO consumption decreased serum TC, LDL-c, and TG less but increased HDL-c more than other plant oils.     

Effect of egg consumption on inflammatory markers: a systematic review and meta-analysis of randomized controlled clinical trials

There is little evidence about whether eggs affect inflammation. The aim of this meta-analysis was to explore the effects of egg consumption on inflammation. A systematic search of online databases (Institute for Scientific Information (ISI), Scopus, Ovid, PubMed, Cochrane) was used to gather clinical trials that assessed the effect of egg consumption on circulating inflammatory biomarkers. Using a random-effects model, pooled weighted mean differences (WMD) and corresponding standard deviations (SD) were calculated. Of the 21 eligible studies found, nine trials were eligible for analysis. Eight trials assessed high-sensitivity C-reactive protein (hs-CRP), four trials assessed interleukin-6 (IL-6), and five trials assessed tumor necrosis factor-alpha (TNF-α). Egg consumption did not affect hs-CRP (WMD 0.24 mg/L; 95% CI: -0.43, 0.90; I² = 53.8; P = 0.48), IL-6 (WMD 0.20 pg/mL; 95% CI: -0.71, 1.11; I² = 69.3; P = 0.50), and TNF-α (WMD: -0.38 pg/mL; 95% CI: -0.87, 0.10; I² = 0.00; P = 0.12) relative to controls. Overall, this meta-analysis revealed that egg consumption had no significant effect on serum biomarkers of inflammation in adults. © 2019 Society of Chemical Industry     

Effect of pistachio on brachial artery diameter and flow-mediated dilatation: A systematic review and meta-analysis of randomized,controlled-feeding clinical studies

Background: Results of previous clinical trials evaluating the effect of pistachio supplementation on endothelial reactivity (ER) are controversial. Aims: We aimed to assess the impact of pistachio on ER through systematic review of literature and meta-analysis of available randomized, controlled-feeding clinical studies (RCTs). Methods: The literature search included SCOPUS, PubMed-Medline, ISI Web of Science and Google Scholar databases up to 1st August 2017 to identify RCTs investigating the impact of pistachio on ER. Two independent reviewers extracted data on study characteristics, methods and outcomes. Overall, the impact of pistachio on ER was reported in 4 trials. Results: The meta-analysis did not suggest a significant change in brachial artery flow-mediated dilatation (FMD) (WMD: +0.28%; 95%CI: ?0.58, 1.13; p = 0.525) while brachial artery diameter (BAD) improved (WMD: +0.04%; 95%CI: 0.03, 0.06; p<0.001) following pistachios consumption. Conclusion: The present meta-analysis suggests a significant effect of pistachios on ER, affecting BAD but not FMD.     

Potato consumption and risk of all cause,cancer and cardiovascular mortality: a systematic review and dose-response meta-analysis of prospective cohort studies

Abstract

A systematic review and meta-analysis of prospective cohort studies was conducted to examine the association of potato consumption and risk of all-cause, cancer and cardiovascular mortality in adults. We searched PubMed, Scopus databases up to September 2018 for all relevant published papers. All analyses were performed on HRs or RRs and 95% CIs. In twenty prospective studies, 25,208 cases were reported for all-cause mortality, 4877 for cancer mortality and 2366 for CVD mortality. No significant association was found between potato consumption and risk of all-cause (0.90; 95% CI: 0.8, 1.02, p?=?0.096) and cancer (1.09; 95% CI: 0.96, 1.24, P?=?0.204) mortality. In addition, no significant linear association was found between each 100?g/d increments in potato consumption and risk of all-cause (P?=?0.7) and cancer (P?=?0.09) mortality. Moreover, nonlinear association between potato consumption and risk of cancer mortality was non-significant (P-nonlinearity?=?0.99). In addition, two of three studies which examined the association of potato consumption with CVD mortality did not find any significant relationship. There was no evidence for publication bias in this study. We failed to find significant association between potato consumption and risk of mortality. Further studies are required to confirm this issue.     

Effects of EPA and DHA on blood pressure and inflammatory factors: a meta-analysis of randomized controlled trials

Abstract

The present study aimed to clarify whether eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have differential effects on blood pressure and inflammatory mediators. A systematic literature search was conducted in PubMed and Scopus updated to Apr. 2018. The mean changes in risk factors of chronic diseases were calculated as weighted mean difference (WMD) by using a random-effects model. Twenty randomized controlled trials (RCTs) were included. The summary estimate showed that EPA intervention significantly reduced systolic blood pressure (SBP) (-2.6?mmHg; 95%confident interval (CI): -4.6, -0.5?mmHg), especially in subjects with dyslipidemia (-3.8?mmHg; 95%CI: -6.7, -0.8?mmHg). The pooled effect indicated that supplemental DHA exerted a significant reduction in diastolic blood pressure (DBP) in subjects with dyslipidemia (-3.1?mmHg; 95%CI: -5.9, -0.2?mmHg). Both EPA (-0.56?mg/L; 95%CI: -1.13, 0.00) and DHA (-0.5?mg/L; 95%CI: -1.0, -0.03) significantly reduced the concentrations of C-reactive protein (CRP), respectively, especially in subjects with dyslipidemia and higher baseline CRP concentrations. Given that limited trials have focused on EPA or DHA intervention on concentrations of interleukin (IL)-6 and tumor necrosis factor (TNF)-α, further RCTs should be explored on these inflammatory factors. The present meta-analysis provides substantial evidence that EPA and DHA have independent (blood pressure) and shared (CRP concentration) effects on risk factors of chronic diseases, and high-quality RCTs with multi-center and large simple-size should be performed to confirm the present findings.     

Effect of resveratrol on blood pressure: A systematic review and meta-analysis of randomized,controlled, clinical trials

Introduction: Results of previous clinical trials evaluating the effect of resveratrol supplementation on blood pressure (BP) are controversial.

Purpose: We aimed to assess the impact of resveratrol on BP through systematic review of literature and meta-analysis of available randomized, controlled clinical trials (RCTs).

Methods: Literature search included SCOPUS, PubMed-Medline, ISI Web of Science and Google Scholar databases up to 17th October 2017 to identify RCTs investigating the impact of resveratrol on BP. Two review authors independently extracted data on study characteristics, methods and outcomes. Overall, the impact of resveratrol on BP was reported in 17 trials.

Results: Administration of resveratrol did not significantly affect neither systolic BP [weighted mean difference (WMD): ?2.5 95% CI:(-5.5, 0.6) mmHg; p=0.116; I²=62.1%], nor diastolic BP [WMD: ?0.5 95% CI:(-2.2, 1.3) mmHg; p=0.613; I²=50.8], nor mean BP [MAP; WMD: ?1.3 95% CI:(-2.8, 0.1) mmHg; p=0.070; I²=39.5%] nor pulse pressure [PP; WMD: ?0.9 95% CI:(-3.1, 1.4) mmHg; p=0.449; I²=19.2%]. However, significant WMDs were detected in subsets of studies categorized according to high resveratrol daily dosage (≥300 mg/day) and presence of diabetes. Meta-regression analysis revealed a positive association between systolic BP-lowering resveratrol activity (slope: 1.99; 95% CI: 0.05, 3.93; two-tailed p= 0.04) and Body Mass Index (BMI) at baseline, while no association was detected neither between baseline BMI and MAP-lowering resveratrol activity (slope: 1.35; 95% CI: ?0.22, 2.91; two-tailed p= 0.09) nor between baseline BMI and PP-lowering resveratrol activity (slope: 1.03; 95% CI: ?1.33, 3.39; two-tailed p= 0.39). Resveratrol was fairly well-tolerated and no serious adverse events occurred among most of the eligible trials.

Conclusion: The favourable effect of resveratrol emerging from the current meta-analysis suggests the possible use of this nutraceutical as active compound in order to promote cardiovascular health, mostly when used in high daily dose (≥300 mg/day) and in diabetic patients.     

The effects of caffeine intake on weight loss: a systematic review and dos-response meta-analysis of randomized controlled trials

Abstract

This systematic review and meta-analysis of randomized controlled trials (RCTs) was performed to summarize the effect of caffeine intake on weight loss. We searched the following databases until November 2017: MEDLINE, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials. The relevant data were extracted and assessed for quality of the studies according to the Cochrane risk of bias tool. We estimated an intake-status regression coefficient (Beta) for each primary study and estimated the overall pooled Beta and SE using random effects meta-analysis on a double-log scale. Heterogeneity between studies was assessed by the Cochran Q statistic and I-squared tests (I²). Thirteen RCTs with 606 participants were included in the meta-analyses. The overall pooled Beta for the effect of caffeine intake was 0.29 (95%CI: 0.19, 0.40; Q = 124.5, I²?=?91.2%) for weigh, 0.23 (95%CI: 0.09, 0.36; Q = 71.0, I²?=?93.0%) for BMI, and 0.36 (95% CI: 0.24, 0.48; Q = 167.36, I²?=?94.0%) for fat mass. For every doubling in caffeine intake, the mean reduction in weight, BMI, and fat mass increased 2 Beta-fold (20.29 = 1.22, 20.23 = 1.17, and 20.36 = 1.28), which corresponding to 22, 17, and 28 percent, respectively. Overall, the current meta-analysis demonstrated that caffeine intake might promote weight, BMI and body fat reduction.     

The effects of quercetin supplementation on lipid profiles and inflammatory markers among patients with metabolic syndrome and related disorders: A systematic review and meta-analysis of randomized controlled trials

Abstract

Aims: This systematic review and meta-analysis of randomized controlled trials (RCTs) was performed to determine the effect of quercetin administration on lipid profiles and inflammatory markers among patients with metabolic syndrome (MetS) and related disorders.

Methods: We searched systematically online databases including Cochrane Library, EMBASE, MEDLINE, and Web of Science to identify the relevant RCTs until November 2018. Q-test and I² statistics were applied to assess heterogeneity among included studies. Data were combined using fixed- or random-effects model and presented as standardized mean difference (SMD) with 95% confidence interval (CI).

Results: Out of 591 citations, 16 RCTs were included in the meta-analysis. The pooled findings showed that quercetin consumption significantly decreased total-cholesterol (SMD = ?0.98; 95% CI, ?1.48, ?0.49; p?<?0.001; I²: 94.0), LDL-cholesterol (SMD = ?0.88; 95% CI, ?1.35, ?0.41; p?<?0.001; I²: 92.7) and C-reactive protein (CRP) levels (?0.64; 95% CI, ?1.03, ?0.25; p?=?0.001; I²: 90.2). While, quercetin supplementation did not significantly affect triglycerides (TG) (SMD = ?0.32; 95% CI, ?0.68, 0.04; p?=?0.08; I²: 84.8), HDL-cholesterol (SMD = 0.20; 95% CI, ?0.20, 0.24; p?=?0.84; I²: 70.6), interleukin 6 (IL-6) (SMD = ?0.69; 95% CI, ?1.69, 0.31; p?=?0.17; I²: 94.5) and tumor necrosis factor-alpha (TNF-α) levels (SMD = ?0.06; 95% CI, ?0.25, 0.14; p?=?0.58; I²: 35.6)

Conclusions: In summary, the current meta-analysis demonstrated that quercetin supplementation significantly reduced total-cholesterol, LDL-cholesterol, and CRP levels, yet did not affect triglycerides, HDL-cholesterol, IL-6 and TNF-α among patients with MetS and related disorders.     

Does cocoa/dark chocolate supplementation have favorable effect on body weight,body mass index and waist circumference? A systematic review,meta-analysis and dose-response of randomized clinical trials

ABSTRACT

Background: Cocoa and dark chocolate (DC) have been reported to be effective for health promotion; however the exact effect of cocoa/DC on anthropometric measures have not been yet defined. Methods: A comprehensive search to identify randomized clinical trials investigating the impact of cocoa/DC on body weight, body mass index (BMI) and waist circumference (WC) was performed up to December 2017. A meta-analysis of eligible studies was performed using random effects model to estimate pooled effect size. Fractional polynominal modeling was used to explore dose-response relationships. Results: A total of 35 RCTs investigated the effects of cocoa/DC on weight, BMI and WC were included. Meta-analysis did not suggest any significant effect of cocoa/DC supplementation on body weight (?0.108 kg, 95% CI ?0.262, 0.046 P = 0.168), BMI (?0.014 kg/m² 95% CI ?0.105, 0.077, P: 0.759,) and WC (0.025 cm 95% CI ?0.083, 0.129, P = 0.640). Subgroup analysis revealed that that weight and BMI were reduced with cocoa/DC supplementation ≥ 30 g chocolate per day in trials between 4-8 weeks. Cocoa/DC consumption resulted in WC reduction in non-linear fashion (r = 0.042, P-nonlinearity = 0.008).Conclusion: Cocoa/DC supplementation does not reduce anthropometric measures significantly. However subgroup analysis regarding dose (≥ 30 g/day) and duration (between 4 to 8 weeks) revealed significant reduction of body weight and BMI.     

The effects of ginger intake on weight loss and metabolic profiles among overweight and obese subjects: A systematic review and meta-analysis of randomized controlled trials

This systematic review and meta-analysis of randomized controlled trials (RCTs) was performed to summarize the effect of ginger intake on weight loss, glycemic control and lipid profiles among overweight and obese subjects. We searched the following databases through November 2017: MEDLINE, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials. The relevant data were extracted and assessed for quality of the studies according to the Cochrane risk of bias tool. Data were pooled using the inverse variance method and expressed as Standardized Mean Difference (SMD) with 95% Confidence Intervals (95% CI). Heterogeneity between studies was assessed by the Cochran Q statistic and I-squared tests (I²). Overall, 14 studies were included in the meta-analyses. Fourteen RCTs with 473 subjects were included in our meta-analysis. The results indicated that the supplementation with ginger significantly decreased body weight (BW) (SMD ?0.66; 95% CI, ?1.31, ?0.01; P = 0.04), waist-to-hip ratio (WHR) (SMD ?0.49; 95% CI, ?0.82, ?0.17; P = 0.003), hip ratio (HR) (SMD ?0.42; 95% CI, ?0.77, ?0.08; P = 0.01), fasting glucose (SMD ?0.68; 95% CI, ?1.23, ?0.05; P = 0.03) and insulin resistance index (HOMA-IR) (SMD ?1.67; 95% CI, ?2.86, ?0.48; P = 0.006), and significantly increased HDL-cholesterol levels (SMD 0.40; 95% CI, 0.10, 0.70; P = 0.009). We found no detrimental effect of ginger on body mass index (BMI) (SMD ?0.65; 95% CI, ?1.36, 0.06; P = 0.074), insulin (SMD ?0.54; 95% CI, ?1.43, 0.35; P = 0.23), triglycerides (SMD ?0.27; 95% CI, ?0.71, 0.18; P = 0.24), total- (SMD ?0.20; 95% CI, ?0.58, 0.18; P = 0.30) and LDL-cholesterol (SMD ?0.13; 95% CI, ?0.51, 0.24; P = 0.48). Overall, the current meta-analysis demonstrated that ginger intake reduced BW, WHR, HR, fasting glucose and HOMA-IR, and increased HDL-cholesterol, but did not affect insulin, BMI, triglycerides, total- and LDL-cholesterol levels.     

Mediterranean diet,cardiovascular disease and mortality in diabetes: A systematic review and meta-analysis of prospective cohort studies and randomized clinical trials

Abstract

To update the clinical practice guidelines for nutrition therapy of the European Association for the Study of Diabetes, we conducted a systematic review and meta-analysis of prospective cohort studies and randomized clinical trials (RCTs) to evaluate the effect of the Mediterranean diet (MedDiet) on the prevention of cardiovascular disease (CVD) incidence and mortality. We searched Medline, EMBASE (through April 20, 2018) and Cochrane (through May 7, 2018) databases. Pooled relative risks (RRs) and 95% confidence interval (CI) were calculated by the generic inverse variance method. A total of 41 reports (3 RCTs and 38 cohorts) were included. Meta-analyses of RCTs revealed a beneficial effect of the MedDiet on total CVD incidence (RR: 0.62; 95% CI: 0.50, 0.78) and total myocardial infarction (MI) incidence (RR: 0.65; 95% CI: 0.49, 0.88). Meta-analyses of prospective cohort studies, which compared the highest versus lowest categories of MedDiet adherence, revealed an inverse association with total CVD mortality (RR: 0.79; 95% CI: 0.77, 0.82), coronary heart disease (CHD) incidence (RR: 0.73; 95% CI: 0.62, 0.86), CHD mortality (RR: 0.83; 95% CI: 0.75, 0.92), stroke incidence (RR: 0.80; 95% CI: 0.71, 0.90), stroke mortality (RR: 0.87; 95% CI: 0.80, 0.96) and MI incidence (RR: 0.73; 95% CI: 0.61, 0.88). The present study suggests that MedDiet has a beneficial role on CVD prevention in populations inclusive of individuals with diabetes.     

Effects of iron supplementation versus dietary iron on the nutritional iron status: Systematic review with meta-analysis of randomized controlled trials

ABSTRACT

This meta-analysis compared the effects of dietary intervention versus iron supplementation on biochemical parameters related to the iron nutritional status in humans. The PubMed, CENTRAL, LILACS, SCIELO, OPENGREY.EU and ClinicalTrials.gov databases were searched for randomized clinical trials that assigned individuals to a dietary intervention or to an iron supplementation regimen, for 12 weeks or more. The primary outcome was the hemoglobin concentration, and secondary outcomes were ferritin, RDW, mean corpuscular volume, soluble transferrin receptor, total iron binding capacity, serum iron, and transferrin saturation. From the 6095 records identified, twelve studies were included, six with children, five with adolescents/adults, and one with pregnant women. In the subgroup of studies that included anemic/iron deficient children, supplementation significantly increased the hemoglobin concentration (weighted mean difference (WMD): 3.19 g/L [95% CI: 1.31, 5.07]) and induced a significantly greater reduction of the soluble transferrin receptor (WMD: ?0.46 mg/L [95% CI: ?0.70, ?0, 21]), when compared to dietary intervention. It also induced a greater reduction of the total binding capacity of iron in adolescents/adults (WMD: ?6.96 μmol/L [95% CI: ?12.70, ?1.21]). Supplementation showed a better effect on hemoglobin recovery in anemic/iron deficient children, while no differences were observed between supplementation and dietary intervention in treating adolescents/adults.     

Efficacy of synbiotic supplementation in patients with nonalcoholic fatty liver disease: A systematic review and meta-analysis of clinical trials: Synbiotic supplementation and NAFLD

ABSTRACT

Objective: We systematically reviewed available randomized clinical trials (RCTs) to elucidate the overall effects of synbiotic supplementation in patients with nonalcoholic fatty liver disease (NAFLD).

Methods: PubMed, Scopus, ISI Web of science and Google Scholar were searched up to December, 2017. All RCTs using synbiotic supplements to treat NAFLD included in this systematic review and meta-analysis. Mean Difference (MD) was pooled using a random-effects model.

Results: Eleven eligible databases from seven RCTs were identified for the present meta-analysis. Our results showed that synbiotic supplementation can decrease body weight, fasting blood sugar, insulin, low density lipoprotein cholesterol, total cholesterol, triglyceride, high-sensitivity C-reactive protein, tumor necrosis factor alpha, alanine transaminase and aspartate transaminase levels among patients with NAFLD. In contrast, synbiotic did not have favorable effects on body mass index (BMI), waist circumference, homeostasis model assessment for insulin resistance (HOMA-IR), and high density lipoprotein cholesterol (HDL) levels compared with the placebo group.

Conclusion: The current study revealed that synbiotic supplementation has favorable effect on inflammatory factors, liver enzymes and some anthropometric indices, lipid profiles and glucose homeostasis parameters in patients with NAFLD.     

Efficacy of vitamin D fortified foods on bone mineral density and serum bone biomarkers: A systematic review and meta-analysis of interventional studies

Abstract

Vitamin D fortified foods (VDFs) were taken into consideration due to the high prevalence of osteoporosis worldwide. However, the efficacy of VDFs on bone health has not been fully examined. The current meta-analysis was conducted in order to summarize the impacts of VDFs on serum 25-hydroxyvitamin D (25(OH)D), bone mineral density (BMD), and bone turnover markers (BTM). A systematic search up to October 2017 was done via PubMed and Scopus search engines. To pool mean differences, random-effects model (the DerSimonian-Laird estimator) was used. Heterogeneity among studies was examined by Cochrane Q test. 20 trials involving 1786 subjects were included in this meta-analysis. Based on random effect model, there were significant effects of VDFs on serum 25(OH)D (MD:16.94?nmol/L 95% CI: 13.38, 20.50; p?<?0.001, I²?=?99.0%), BMD (MD: 0.03?gr/cm²; 95% CI: (0.02, 0.05); p?<?0.001, I²?=?58.8%) and paratormone hormone (PTH; MD:?9.22; 95% CI: (?14.97, ?3.46); p?=?0.002, I²?=?98.8%). VDFs may increase serum 25(OH)D and BMD while decrease serum PTH levels. We did not find any beneficial effect of VDFs on BTM.