The effect of crocin supplementation on lipid concentrations and fasting blood glucose: A systematic review and meta-analysis and meta-regression of randomized controlled trials.

OBJECTIVE: This meta-analysis aimed to assess the effects of crocin supplementation on fasting blood glucose (FBG) and lipid profile levels in clinical trial studies. DESIGN: A systematic literature search was performed in PubMed, Scopus, Embase, Web of Science, and the Cochrane Library databases for clinical trials published from the beginning up to November 2019. Of the 547 papers identified from all searched databases, eight eligible studies with nine effect sizes have all needed criteria for inclusion in this meta-analysis. RESULTS: Results of the pooled random-effect size analysis showed just a significant decreasing effect of crocin supplementation on FBG (WMD: -6.52 mg/l, 95 % CI, -11.96, -1.08; p = 0.019) and TC (WMD: -4.64 mg/l, 95 % CI, -8.19, -1.09; p = 0.010). Crocin supplements did not have any significant effect on serum TG (p = 0.144) levels, LDL-C (p = 0.161), and HDL-C (p = 0.872) levels. Results showed that crocin supplementation could beneficially have effect on TG level only when trial duration less than 12 weeks and LDL-C levels in trials that used high dose intervention and trials that conducted on subjects with metabolic disorders. However, crocin supplementation did not significantly change FBG in trials that used low dose intervention. Meta-regression analysis indicated a linear relationship between the duration of intervention and significant change in FBG (p = 0.019). CONCLUSION: Results of this systematic review and meta-analysis study have shown that crocin supplementation can decrease significantly FBS and TC without any beneficial effects on TG, LDL-C, and HDL-C levels.

The effects of carnitine supplementation on clinical characteristics of patients with non-alcoholic fatty liver disease: A systematic review and meta-analysis of randomized controlled trials.

OBJECTIVE: The beneficial effects of carnitine supplementation on nonalcoholic fatty liver disease are unclear. We conducted a systematic review and meta-analysis to evaluate the effects of carnitine supplementation on liver function, lipid profile, body mass index, body weight, and homeostasis model assessment of insulin resistance in patients with nonalcoholic fatty liver disease. METHODS: A comprehensive search of PubMed, Web of Science, Scopus, Cochrane Library, and Google Scholar databases were performed. Only randomized placebo-controlled human studies that examined the effects of carnitine supplementation on liver function, lipid profile, body mass index, body weight, and homeostasis model assessment of insulin resistance up to September 2019 were included. Fixed effects or random-effects models were applied to compute the pooled effect size. Heterogeneity assessments were performed using Cochran's Q test and I-squared statistics. The quality of the studies was assessed using the Jaded scale. RESULTS: A total of 5 articles were selected, including 334 individuals (167 in control and 167 in intervention groups). The results demonstrated that carnitine supplementation significantly reduced homeostasis model assessment of insulin resistance (HOMA-IR) (WMD: -0.91; 95 % CI: -1.11, -0.72; p < 0.001, I2 = 0.0 %) and the levels of aspartate aminotransferase (AST) (WMD: -16.62; 95 % CI: -28.11, -5.14; IU/l; p = 0.005, I2 = 93.5 %), alanine aminotransferase (ALT) (WMD: -33.39; 95 % CI: -45.13, -21.66; IU/l; p < 0.001, I2 = 93.4 %), and triglycerides (TG) (WMD: -22.13; 95 % CI: -38.91, -5.34; mg/dl; p = 0.01; I2 = 0.0 %). However, the results of the pooled effect size did not show any significant effect of carnitine supplementation on body mass index (BMI) (WMD: 0.07; 95 % CI: -0.15, 0.29; p = 0.55; I2 = 0.0 %), body weight (WMD: -0.28; 95 % CI: -2.23, 1.68; p = 0.78; I2 = 45.7 %), the levels of gamma-glutamyl transferase (γGT) (WMD: -11.31; 95 % CI: -24.35, 1.73; IU/l; p = 0.09, I2 = 61.1 %), cholesterol (WMD: -13.58; 95 % CI: -46.77, 19.60; mg/dl; p = 0.42; I2 = 94.9 %), high-density lipoprotein-cholesterol (HDL-C) (WMD: 1.36; 95 % CI: -0.96, 3.68; mg/dl; p = 0.25; I2 = 64.7 %), and low density lipoprotein-cholesterol (LDL-C) (WMD: -14.85; 95 % CI: -45.43, 15.73; mg/dl; p = 0.34; I2 = 96.4 %). CONCLUSIONS: This analysis shows that carnitine supplementation for patients with nonalcoholic fatty liver disease demonstrates a reduction in AST, ALT, TG levels and HOMA-IR. However, no significant effect of carnitine supplementation was observed on BMI, body weight, the levels of γGT, TC, HDL-cholesterol and LDL-cholesterol.

Effects of ginseng on C-reactive protein level: A systematic review and meta-analysis of clinical trials.

OBJECTIVE: The aim of this meta-analysis was to assess effects of ginseng supplementation on CRP/hs-CRP levels in clinical trial studies. DESIGN: A systematic literature search was carried out for clinical trials published in ISI web of Science, Scopus, PubMed and Cochrane Library databases from the beginning to 16th February 2018. Of 83 articles found in the first step of the systematic search, seven studies with nine arms included in this meta-analysis. RESULTS: Results of pooled random-effect size analysis of nine trials showed non-significant decreasing effects of ginseng supplementation on CRP level (WMD: -0.1 mg/l, 95% CI, -0.26, 0.1; P = 0.27) with significant heterogeneity shown within the studies. The subgroup analysis showed that ginseng supplementation could significantly reduce CRP level by 0.51 (95% CI: -0.68, -0.34; P < 0001, test for heterogeneity: P = 0.44, I2 = 0.0%) in patients with a baseline serum CRP level of greater than 3 mg/dl. Trial duration and dose of ginseng supplementation included no significant effects on CRP level in this meta-analysis. CONCLUSION: Results of the current meta-analysis study have shown that ginseng supplementation can decrease significantly serum CRP/hsCRP levels in patients with elevated serum level of this inflammatory marker.

Effect of Q10 supplementation on body weight and body mass index: A systematic review and meta-analysis of randomized controlled clinical trials.

AIMS: This meta-analysis study was carried out to assess the effects of coenzyme Q10 supplementation on body weight and body mass index of patients in randomized controlled clinical trial studies. MATERIALS AND METHODS: A comprehensive systematic search of literature was performed through ISI web of sciences, PubMed, Scopus and Cochrane library databases up to February 2018 which was supplemented by manual search of the references list of included studies. From a total of 1579 identified articles, only 17 trials with 14 and 14 effect-sizes were included for pooling the effects of co-enzyme Q10 supplementation on body weight and body mass index, respectively. RESULTS: Results of random-effect size meta-analysis showed that supplementation with coenzyme Q10 had no significant decreasing effects on body weight (WMD: 0.28 kg; 95% CI = -0.91, 1.47; P = 0.64) and BMI (WMD: -0.03; 95% CI = -0.4, 0.34; P = 0.86) of study participants. Subgroup analysis revealed that dosage of Q10 and trial duration could not differ the results of Q10 supplementation. CONCLUSION: Results of this meta-analysis study failed to show any beneficial effect of coenzyme Q10 supplementation on body weight and BMI of patients in clinical trial studies.

Association between Circulating Irisin and C-Reactive Protein Levels: A Systematic Review and Meta-Analysis.

BACKGROUND: Although previous studies have demonstrated that irisin plays an anti-inflammatory role in the body, conflicting results have been reported regarding the correlation between serum levels of irisin and C-reactive protein (CRP). The present meta-analysis was conducted to further investigate the correlation between irisin and CRP levels. METHODS: We systematically searched PubMed, the Cochrane Library, Web of Science, Embase, SCOPUS, and Ovid to retrieve studies assessing the correlation between irisin and CRP levels. Meta-analyses were performed using a random-effects model, and the I² index was used to evaluate heterogeneity. RESULTS: Of the 428 studies that were initially found, 14 studies with 2,530 participants met the inclusion criteria for the meta-analysis. The pooled effect size was calculated as 0.052 (95% confidence interval, -0.047 to 0.152; P=0.302). Subgroup analyses identified s ignificant, positive, but weak correlations between CRP and irisin levels in cohort studies, studies conducted among healthy participants, studies in which the male-to-female ratio was less than 1, in overweight or obese subjects, and in studies with a sample size of at least 100 participants. CONCLUSION: The present meta-analysis found no overall significant correlation between irisin and CRP levels, although a significant positive correlation was found in overweight or obese subjects. Well-designed studies are needed to verify the results of the present meta-analysis.

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.

Effect of vitamin E supplementation on blood pressure: a systematic review and meta-analysis.

Although emerging evidence suggests that vitamin E may contribute to blood pressure improvement, the effects of vitamin E on systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) are still controversial. The aim was to evaluate the influence of vitamin E on SBP, DBP, and MAP through meta-analysis. We identified all studies that assessed the effect of vitamin E supplementation on SBP, DBP, and MAP from PubMed/Medline, SCOPUS, and Google scholar up to March 2018. Weighted mean differences (WMD) and 95% confidence interval (CI) were expressed as effect size. Pre-specified subgroup analysis was conducted to evaluate potential sources of heterogeneity. Meta-regression analyses were performed to investigate association between blood pressure-lowering effects of vitamin E and duration of follow-up and dose of treatment. Eighteen trials, comprising 839 participants met the eligibility criteria. Results of this study showed that compared to placebo, SBP decreased significantly in vitamin E group (WMD = -3.4 mmHg, 95% CI = -6.7 to -0.11, P < 0.001), with a high heterogeneity across the studies (I2 = 94.0%, P < 0.001). Overall, there were no significant effects on DBP and MAP. This meta-analysis suggested that vitamin E supplements decreased only SBP and had no favorable effect on DBP and MAP.