The effect of exercise training on serum concentrations of chemerin in patients with metabolic diseases: a systematic review and meta-analysis.

CONTEXT: Elevated serum concentrations of chemerin is a significant factor in the development of metabolic disorders. OBJECTIVE: This systematic review and meta-analysis evaluated the influence of exercise training on serum concentrations of chemerin in patients with metabolic diseases. METHODS: Thirteen studies including 463 participants were included and analysed using a random-effects model to calculate weighted mean differences with 95% confidence intervals. RESULTS: Results indicated that exercise training significantly decreased serum concentrations of chemerin in patients with metabolic diseases when compared with controls. Subgroup analysis showed that exercise training resulted in decreases in serum concentrations of chemerin in men, however, this was not significant in women. Moreover, subgroup analyses based on the type of exercise did not reveal differential effects on serum concentrations of chemerin. CONCLUSION: Exercise training may produce improvements in serum concentrations of chemerin in patients with metabolic diseases. Further longer-term studies are needed to confirm these findings.

The effects of exercise training on serum concentrations of chemerin in individuals with overweight and obesity: a systematic review, meta-analysis, and meta-regression of 43 clinical trials.

CONTEXT: Elevated serum concentrations of chemerin is a significant factor in the development of metabolic disorders in individuals with overweight and obesity. OBJECTIVE: This systematic review, meta-analysis, and meta-regression evaluated the effects of exercise training on serum concentrations of chemerin in individuals with overweight and/or obesity. METHODS: Studies published up to January 2021 were identified through four databases. Forty-three studies including 1271 participants were included and analysed using a random-effects model to calculate weighted mean differences with 95% confidence intervals. RESULTS: Results indicated that exercise training significantly decreased serum concentrations of chemerin in individuals with overweight and/or obesity. Subgroup analysis showed that all types of exercise (aerobic, resistance, and combined training) interventions but not high-intensity interval training decreased serum concentrations of chemerin. Subgroup analysis based on baseline body mass index (BMI), gender, and intervention duration showed significant declines in serum concentrations of chemerin. Meta-regression analysis indicated a linear relationship between changes in body fat percentage (BFP) with serum concentrations of chemerin. CONCLUSION: Exercise training may decrease serum concentrations of chemerin in individuals with overweight and/or obesity. The chemerin-lowering effects of exercise might be related to declines in BFP. Further studies are needed to confirm these findings.

The effects of oral magnesium supplementation on glycaemic control in patients with type 2 diabetes: a systematic review and dose-response meta-analysis of controlled clinical trials.

The current systematic review and meta-analysis were conducted to evaluate the effects of oral Mg supplementation on glycaemic control in type 2 diabetes mellitus (T2DM) patients. Related articles were found by searching the PubMed, SCOPUS, Embase and Web of Science databases (from inception to 30 February 2020). A one-stage robust error meta-regression model based on inverse variance weighted least squares regression and cluster robust error variances was used for the dose-response analysis between Mg supplementation and duration of intervention and glycaemic control factors. Eighteen eligible randomised clinical trials were included in our final analysis. The dose-response testing indicated that the estimated mean difference in HbA1c at 500 mg/d was -0·73 % (95 % CI: -1·25, -0·22) suggesting modest improvement in HbA1c with strong evidence (P value: 0·004). And in fasting blood sugar (FBS) at 360 mg/d was -7·11 mg/dl (95 % CI: -14·03, -0·19) suggesting minimal amelioration in FBS with weak evidence (P value: 0·092) against the model hypothesis at this sample size. The estimated mean difference in FBS and HbA1c at 24 weeks was -15·58 mg/dl (95 % CI: -24·67, -6·49) and -0·48 (95 % CI: -0·77, -0·19), respectively, suggesting modest improvement in FBS (P value: 0·034) and HbA1c (P value: 0·001) with strong evidence against the model hypothesis at this sample size. Oral Mg supplementation could have an effect on glycaemic control in T2DM patients. However, the clinical trials so far are not sufficient to make guidelines for clinical practice.

Effects of betaine supplementation on cardiovascular markers: A systematic review and Meta-analysis.

Controversy regarding the effects of betaine supplementation on cardiovascular markers has persisted for decades. This systematic review and meta-analysis compared the effects of betaine supplementation on cardiovascular disease (CVD) markers. Studies examining betaine supplementation on CVD markers published up to February 2021 were identified through PubMed, the Cochrane Library, Web of Science, Embase, and SCOPUS. Betaine supplementation had a significant effect on concentrations of betaine (MD: 82.14 µmol/L, 95% CI: 67.09 to 97.20), total cholesterol (TC) (MD: 14.12 mg/dl, 95% CI%: 9.23 to 19.02), low-density lipoprotein (LDL) (MD: 10.26 mg/dl, 95% CI: 6.14 to 14.38)], homocysteine (WMD: -1.30 micromol/L, 95% CI: -1.61 to -0.98), dimethylglycine (DMG) (MD: 21.33 micromol/L, 95% CI: 13.87 to 28.80), and methionine (MD: 2.06 micromol/L, 95% CI: 0.23 to 3.88). Moreover, our analysis indicated that betaine supplementation did not affect serum concentrations of triglyceride (TG), high-density lipoprotein (HDL), fasting blood glucose (FBG), C-reactive protein (CRP), liver enzymes [alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT)], and blood pressure. Our subgroup analysis suggested that a maximum dose of 4 g/d might have homocysteine-lowering effects without any adverse effect on lipid profiles reported with doses of ≥4 g/d. In conclusion, the present systematic review and meta-analysis supports the advantage of a lower dose of betaine supplementation (<4 g/d) on homocysteine concentrations without the lipid-augmenting effect observed with a higher dosage.

Betaine supplementation fails to improve body composition: a systematic review and meta-analysis.

Previous studies evaluating the effects of betaine supplementation on body composition offer contradictory findings. This systematic review and meta-analysis assessed the effects of betaine supplementation on body composition indices (body mass (BM), BMI, body fat percentage (BFP), fat mass (FM), fat-free mass (FFM)), and dietary intakes. Studies examining the effects of betaine supplementation on body composition and dietary intakes published up to August 2021 were identified through PubMed, the Cochrane Library, Web of Science, Embase, SCOPUS and Ovid databases. Betaine supplementation failed to significantly affect BM ((weighted mean difference (WMD): -0·40 kg, 95 % CI -1·46, 0·64), P = 0·447), BMI ((WMD: -0·05 kg/m2, 95 % CI -0·36, 0·25), P = 0·719), BFP ((WMD: 0·26 %, 95 % CI -0·82, 1·36), P = 0·663), FM ((WMD: -0·57 kg, 95 % CI -2·14, 0·99), P = 0·473) and FFM ((WMD: 0·61 kg, 95 % CI -1·27, 2·49), P = 0·527). Subgroup analyses based on participant's age (< 40 and > 40 years), sex, BMI, trial duration (< 8 and ≥ 8 weeks), betaine supplementation dosage (< 4 and ≥ 4 g) and health status (healthy or unhealthy) demonstrated similar results. Other than a potential negligible increase in protein intake (WMD: 3·56 g, 95 % CI 0·24, 6·88, P = 0·035), no changes in dietary intakes were observed following betaine supplementation compared with control. The present systematic review and meta-analysis does not show any beneficial effects of betaine supplementation on body composition indices (BM, BMI, FM and FFM).

Effect of green coffee bean extract supplementation on liver function and inflammatory biomarkers: A meta-analysis of randomized clinical trials.

Inflammation is considered a major contributor to non-alcoholic fatty liver disease (NAFLD) and several chronic diseases such as, cardiovascular disease and type two diabetes. Green coffee bean extract (GCBE) supplementation has been suggested to enhancing antioxidant capacity in people with obesity but results across studies are mixed. We conducted a meta-analysis of randomized controlled trials of GCBE supplementation in overweight/obese with normal liver function and NAFLD adults with ALT, AST, γ-GTP, ALP, LDH, CRP, IL-6, and TNF-α as outcomes by searching PubMed and other databases. Eight studies were included, totaling 330 participants randomized to GCBE supplementation or placebo ranging from 50 mg/day to 1200 mg/day for 8-12 weeks. GCBE supplementation resulted in lower levels of TNF-α (mean difference = 1.37 pg/mL [95% CI = 0.97-1.76]; p < 0.00001). No significant difference was found in the remaining markers. In conclusion, GCBE supplementation attenuated TNF-α, a circulating inflammatory marker mediator which may be linked with lower systemic inflammation. However, potential cellular and molecular mechanisms by which GCBE exerts this positive effect warrants further investigations in human model studies.

The Effects of Magnesium Supplementation on Blood Pressure and Obesity Measure Among Type 2 Diabetes Patient: a Systematic Review and Meta-analysis of Randomized Controlled Trials.

In this study, we aimed to systematically review the literature to evaluate the effects of magnesium (Mg) supplementation on blood pressure (BP) and obesity measure among patients with type 2 diabetes mellitus (T2DM). Major electronic databases of Web of Science, the Cochrane library, PubMed, and Scopus were searched completely from the inception until 15 October 2019 to identify randomized clinical trials (RCTs) pertaining to the topic of interest. All outcomes were pooled using a random-effects model and expressed as weighted mean differences (WMD) with 95% confidential intervals (CI). Heterogeneity, sensitivity analysis, and publication bias were also assessed using standard methods. The pooled analysis of five RCTs showed that Mg supplementation did not affect body weight (WMD: - 0.01 kg, 95% CI: - 0.36 to 0.33), BMI (WMD: - 0.07, 95% CI: - 0.18 to 0.04), and waist circumference (WMD: 0.12, 95% CI: - 1.24 to 1.48) in T2DM patients compared to the control groups of the patients who received placebo. However, pooling seven RCTs together showed significant reduction of systolic blood pressure (WMD: - 5.78 mmHg, 95% CI: - 11.37 to - 0.19) and diastolic blood pressure (WMD: - 2.50 mmHg, 95% CI: - 4.58 to - 0.41) in T2DM patients. Furthermore, subgroup analysis by dose of intervention, intervention duration, and type of intervention suggested that Mg supplementation for > 12 weeks, in doses higher than 300 mg/day or inorganic forms, could significantly decrease both systolic and diastolic BP in T2DM patients. Based on the findings, Mg supplementation has beneficial effects on BP in type 2 diabetes patients independent of body weight status. However, further investigations are needed to provide more reliable evidences.

Effect of L-Carnitine Supplementation on Lipid Profiles of Patients with Liver Disease: A Systematic Review and Meta-Analysis.

Results of previous studies regarding the effect of L-carnitine on lipid profiles in the patients with liver diseases are contradictory. This meta-analysis was performed to assess the effect of L-carnitine on serum levels of low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglyceride (TG), and total cholesterol (TC) in overweight patients with liver diseases. A systematic search was carried out using the Web of Science, PubMed, Scopus, and Cochrane library databases to identify articles published before April 2019 investigating the effects of L-carnitine supplementation on patients with liver disease. There was no language or time limitation for the studies. A meta-analysis was carried out using both the random and fixed effects model where appropriate, and I2 index were used to evaluate heterogeneity. These results indicated that L-carnitine supplementation significantly reduces blood levels of TC and TG in patients with liver disease, whereas carnitine had no effect on the levels of HDL and LDL. The reducing effect of L-carnitine on both TC and TG was found following long-term carnitine supplementation (≥24 weeks), supplementation with doses less than or equal to 2,000 mg/d, and in patients with chronic hepatitis C. This meta-analysis indicates the beneficial effect of L-carnitine on TC and TG in overweight patients with liver disease, particularly patients with chronic hepatitis C, in both long-term and low doses.

The effects of L-carnitine supplementation on lipid concentrations inpatients with type 2 diabetes: A systematic review and meta-analysis of randomized clinical trials.

This meta-analysis was performed to assess the effect of L-carnitine supplementation on lipid profile. A systematic search were conducted in PubMed and Scopus to identify randomized clinical trials (RCTs) which evaluated the effects of L-carnitine on lipid profile. Pooled effect sizes were measured using random-effect model (Dersimonian-Laird). Meta-analysis showed that L-carnitine supplementation significantly reduced total cholesterol (TC) (weighted mean difference [WMD]: -8.17 mg/dL; 95% CI,-14.68 to -1.65, I2=52.2%, P = 0.041). Baseline level of TC was a source of heterogeneity, with a greater effect in studies with a baseline level of more than 200 mg/d (WMD: -11.93 mg/dL; 95% CI, -20.80 to-3.05). L-carnitine also significantly decreased low-density lipoprotein-cholesterol (LDL-C) (WMD:-5.22 mg/dL; 95% CI, -9.54 to -0.91, I2=66.7%, P = 0.010), and LDL-C level <100 mg/dL), trial duration,and L-carnitine dosage were potential sources of heterogeneity. L-carnitine supplementation appeared to have no significant effect on high-density lipoprotein-cholesterol (HDL-C) (WMD: -0.51 mg/dL;95% CI, -2.45 to 1.44) and triglyceride (TG) (WMD: 2.80 mg/dL; 95% CI, -8.09 to 13.69). This meta-analysisrevealed that L-carnitine may have favorable effects on lipid profile, especially LDL-C and TC. However, further RCTs are needed to confirm the veracity of these results, particularly among hyperlipidemic patients.

Effect of L-carnitine on liver enzymes and biochemical factors in hepatic encephalopathy: A systematic review and meta-analysis.

BACKGROUND AND AIMS: We aimed to investigate the effect of L-carnitine on biochemical factors including ammonia, bilirubin, albumin, alanine aminotransferase, aspartate aminotransferase (AST), blood urea nitrogen (BUN), and creatinine (Cr) in patients with hepatic encephalopathy (HE). METHODS: A systematic search was carried out in Web of Science, PubMed, Scopus, and Cochrane Library databases to find articles related to the effect of L-carnitine supplementation in patients with HE, up to 7 February 2019. There was no language and time limitation. Meta-analyses were carried out using both the random and fixed effects models where appropriate, and I2 index was used to evaluate the heterogeneity. RESULTS: Search yielded 3462 publications. Nine randomized clinical trials with 779 patients were eligible. L-carnitine supplementation significantly reduced blood levels of ammonia. Furthermore, our results indicated that L-carnitine supplementation significantly reduced blood levels of bilirubin, AST, BUN, and Cr in patients with HE. Subgroup analysis demonstrated that L-carnitine significantly reduced ammonia in patients with all the ages, long and short duration of the supplementation, doses less or higher than 4000 mg/day, any route of treatment (intravenous or oral), and in patients with any grade of the symptoms of HE. Moreover, we found that L-carnitine significantly increased circulating levels of albumin in HE patients. CONCLUSIONS: Present systematic review and meta-analysis revealed that L-carnitine supplementation significantly reduced blood levels of ammonia, bilirubin, AST, BUN, and Cr in HE patients. Moreover, we found that L-carnitine significantly increased circulating levels of albumin. However, further large-scale randomized clinical trials are needed.

Effect of Calcium­Vitamin D Co­Supplementation on Insulin, Insulin Sensitivity, and Glycemia: A Systematic Review and Meta-Analysis of Randomized Clinical Trials.

We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to assess the effect of calcium-vitamin D co­supplementation on insulin, insulin sensitivity, and glycemia. A systematic search was carried out in Web of Science, PubMed, EMBASE, Scopus, and Cochrane library without any language and time restriction up to 12 August 2018, to retrieve the RCTs, which examined the effect of calcium and vitamin D co-supplementation on fasting blood glucose (FBG), insulin, HOMA-B, HOMA-IR, and QUICKI. Meta-analyses were carried out using a random effects model, and I2 indexes were used to evaluate the heterogeneity. Search yielded 2225 publications. Twelve RCTs with 4395 patients were eligible. Results demonstrated that calcium and vitamin D co­supplementation had significantly reducing effects on FBG, HOMA-IR and circulating levels of insulin. As the subgroup analysis demonstrated, short-term (≤12 weeks) calcium and vitamin D co­supplementation had a significant reducing effect on FBG. However, beneficial effects of calcium and vitamin D co­supplementation on circulating level of insulin and HOMA-IR were seen in both short-term and long-term (>12 weeks) supplementations. Furthermore, we found that high doses of vitamin D and calcium co-supplementation (vitamin D≥2000 mg/day and calcium≥1000 mg/day) had significantly reducing effects on FBG, HOMA-IR and insulin. Present meta-analysis indicated the beneficial effects of high-dose and short-term combined vitamin D and calcium supplementation on insulin, insulin resistance and glycemia; however, further large-scale RCTs with adequate and multiple dosing schedules are needed.