Effects of melatonin supplementation on blood lipid concentrations: A systematic review and meta-analysis of randomized controlled trials.

Melatonin supplementation may be associated with blood lipids improvement; however, the current evidence from randomized controlled trials (RCTs) is inconsistent. The present study aimed to systematically review and analyze RCTs assessing the effects of melatonin supplementation on blood lipids. A comprehensive literature search in several database was performed up to January 2017. Quantitative data synthesis was performed using a fixed or random-effects model, with weight mean difference (WMD) and 95% confidence intervals (CI). Standard methods were used for assessment of heterogeneity, meta-regression, sensitivity analysis and publication bias. A total of 8 RCTs were eligible. Meta-analysis suggested a significant association between melatonin supplementation and a reduction in triglycerides (WMD: -31.54 mg/dL, 95% CI: -50.71, -12.38, p = 0.001), and total cholesterol levels (WMD: -18.48 mg/dL, 95% CI: -35.33, -1.63, p = 0.032), while no significant effect on LDL-C (WMD: -2.37 mg/dL, 95% CI: -11.61, -6.86, p = 0.615) and HDL-C (WMD: 1.28 mg/dL, 95% CI: -0.66, 3.23, p = 0.197) was found. In sub-group analysis, a significant decrease in triglycerides was found at doses ≥8 mg/d and when trials last ≥8 weeks. In addition, a significant decrease of total cholesterol was found at doses ≥8 mg/d and when total cholesterol baseline levels were ≥200 mg/dL. Melatonin supplementation has significant effects on triglycerides and total cholesterol levels, which was more evident in higher dose and longer duration and also in a higher concentration of cholesterol levels. Further studies are required to determine the benefits of melatonin on lipid profile.

Mohammadi-Sartang M ，Ghorbani M ，Mazloom Z 《-》

Nigella sativa (black seed) effects on plasma lipid concentrations in humans: A systematic review and meta-analysis of randomized placebo-controlled trials.

The effects of Nigella sativa (NS) on plasma lipid concentrations are controversial. A systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to obtain a conclusive result in humans. PubMed-Medline, SCOPUS, Web of Science, and Google Scholar databases were searched (up to August 2015) to identify RCTs investigating the impact of NS on total cholesterol, LDL-cholesterol (LDL-C), HDL-cholesterol (HDL-C), and triglycerides concentrations. A random-effects model and the generic inverse variance weighting method were used for quantitative data synthesis. Meta-regression, sensitivity analysis, and publication bias assessments were performed using standard methods. A total of 17 RCTs examining the effects of NS on plasma lipid concentrations were included. Meta-analysis suggested a significant association between NS supplementation and a reduction in total cholesterol (weighed-mean-difference [WMD]: -15.65mg/dL, 95% CI: -24.67, -6.63, p=0.001), LDL-C (WMD: -14.10mg/dL, 95% CI: -19.32, -8.88, p<0.001), and triglyceride levels (WMD: -20.64mg/dL, 95% CI: -30.29, -11.00, p<0.001). No significant effect on HDL-C concentrations (WMD: 0.28mg/dL, 95% CI: -1.96, 2.53, p=0.804) was found. A greater effect of NS seed oil versus seed powder was observed on serum total cholesterol and LDL-C levels, and an increase in HDL-C levels was found only after NS seed powder supplementation. NS has a significant impact on plasma lipid concentrations, leading to lower total cholesterol, LDL-C, and TG levels while increased HDL-C is associated with NS powder only. Further RCTs are needed to explore the NS benefits on cardiovascular outcomes.

Sahebkar A ，Beccuti G ，Simental-Mendía LE ，Nobili V ，Bo S ... -  《-》

A systematic review and meta-analysis of the impact of Spirulina supplementation on plasma lipid concentrations.

The impact of Spirulina supplementation on plasma lipid concentrations has not been conclusively studied. Therefore the aim of the meta-analysis was to assess the effect of Spirulina supplementation on plasma lipid concentrations. We searched PubMed and Scopus (up to July 03, 2015) to identify randomized controlled trials (RCTs) that investigate the effect Spirulina supplementation on plasma lipid concentrations. Meta-analysis and meta-regression were performed using random-effects models. Random-effect meta-analysis of data from 7 RCTs showed a significant effect of supplementation with spirulina in reducing plasma concentrations of total cholesterol (WMD: -46.76 mg/dL, 95% CI: -67.31 to -26.22, p < 0.001), LDL-C (WMD: -41.32 mg/dL, 95% CI: -60.62 to -22.03, p < 0.001) and triglycerides (WMD: -44.23 mg/dL, 95% CI: -50.22 to -38.24, p < 0.001), and elevating those of HDL-C (WMD: 6.06 mg/dL, 95% CI: 2.37-9.76, p = 0.001). The impact of spirulina on plasma concentrations of total cholesterol (slope: -1.32; 95% CI: -8.58 to 5.93; p = 0.720), LDL-C (slope: -1.01; 95% CI: -8.03 to 6.02; p = 0.778), triglycerides (slope: -1.39; 95% CI: -4.26 to 1.48; p = 0.342) and HDL-C (slope: 1.79, 95% CI: -0.48 to 4.05; p = 0.122) was independent of administered dose. Regarding duration of supplementation with Spirulina, significant associations were found with changes in plasma concentrations of total cholesterol (slope: -1.77; 95% CI: -3.48 to -0.07; p = 0.042), LDL-C (slope: -1.73; 95% CI: -3.40 to -0.06; p = 0.042) HDL-C (slope: 0.91; 95% CI: 0.68-1.14; p < 0.001) and triglycerides (slope: -1.39; 95% CI: -2.28 to -0.50; p = 0.002). This meta-analysis showed a significant effect of supplementation with Spirulina in reducing plasma concentrations of total cholesterol, LDL-C, triglycerides and elevating those of HDL-C.

Serban MC ，Sahebkar A ，Dragan S ，Stoichescu-Hogea G ，Ursoniu S ，Andrica F ，Banach M ... -  《-》

The effects of cinnamon supplementation on blood lipid concentrations: A systematic review and meta-analysis.

Cinnamon is a rich botanical source of polyphenols, whose positive effects on blood lipid concentrations have been hypothesized, but have not been conclusively studied. The objective of the study was to systematically review and evaluate the effect of administration of cinnamon on blood lipid concentrations. We assessed 13 randomized controlled trials with 750 participants investigating the effect of cinnamon supplementation on blood lipid concentrations. A meta-analysis was performed using random effect models, with weighted mean differences (WMDs; with 95% confidence interval [CI]) for endpoints calculated using a random effects model. No statistically significant effect of cinnamon was observed on blood low-density lipoprotein cholesterol (LDL-C; WMD: -0.16 mmol/L [-6.19 mg/dL], 95% CI: -0.35, 0.03 [-13.53, 1.16], P = .10) and high-density lipoprotein cholesterol (HDL-C; WMD: 0.05 mmol/L [1.92 mg/dL], 95% CI: -0.03, 0.12 [-0.03, 4.64], P = .21) concentrations. However, a statistically significant reduction in blood triglycerides (WMD: -0.27 mmol/L [-23.91 mg/dL], 95% CI: -0.39, -0.14 [-34.54, -12.40], P < .01) and total cholesterol concentrations (WMD: -0.36 mmol/L [-13.92 mg/dL], 95% CI: -0.63, -0.09 [-24.36, -3.48], P < .01) was observed. HDL-C was significantly elevated after the omission of 1 study (WMD: 0.04 mmol/L [1.54 mg/dL], 95% CI: 0.03, 0.06 [1.16, 2.32], P < .01) during our sensitivity analysis. A meta-regression analysis was conducted, and no significant association was found between changes in lipid parameters and cinnamon dose. In contrast, changes in blood levels of total cholesterol (slope: 0.09; 95% CI: 0.02, 0.16; P < .01), LDL-C (slope: 0.05; 95% CI: 0.001, 0.10; P = .05) and triglycerides (slope: 0.06; 95% CI: 0.04, 0.09; P < .01) were significantly and positively associated with the duration of supplementation. No statistically significant association was found between blood HDL-C changes and duration of supplementation. Cinnamon supplementation significantly reduced blood triglycerides and total cholesterol concentrations without any significant effect on LDL-C and HDL-C.

Maierean SM ，Serban MC ，Sahebkar A ，Ursoniu S ，Serban A ，Penson P ，Banach M ，Lipid and Blood Pressure Meta-analysis Collaboration (LBPMC) Group ... -  《-》

The Effects of L-Carnitine Supplementation on Serum Lipids: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

The findings of trials investigating the effects of L-carnitine administration on serum lipids are inconsistent. This meta-analysis of randomized controlled trials (RCTs) was performed to summarize the effects of L-carnitine intake on serum lipids in patients and healthy individuals. Two authors independently searched electronic databases including MEDLINE, EMBASE, Cochrane Library, Web of Science, PubMed and Google Scholar from 1990 until August 1, 2019, in order to find relevant RCTs. The quality of selected RCTs was evaluated using the Cochrane Collaboration risk of bias tool. Cochrane's Q test and I-square (I2) statistic were used to determine the heterogeneity across included trials. Weight mean difference (SMD) and 95% CI between the two intervention groups were used to determine pooled effect sizes. Subgroup analyses were performed to evaluate the source of heterogeneity based on suspected variables such as, participant's health conditions, age, dosage of L-carnitine, duration of study, sample size, and study location between primary RCTs. Out of 3460 potential papers selected based on keywords search, 67 studies met the inclusion criteria and were eligible for the meta-analysis. The pooled results indicated that L-carnitine administration led to a significant decrease in triglycerides (WMD: -10.35; 95% CI: -16.43, -4.27), total cholesterol (WMD: -9.47; 95% CI: - 13.23, -5.70) and LDL-cholesterol (LDL-C) concentrations (WMD: -6.25; 95% CI: -9.30, -3.21), and a significant increase in HDL-cholesterol (HDL-C) levels (WMD: 1.39; 95% CI: 0.21, 2.57). L-carnitine supplementation did not influence VLDL-cholesterol concentrations. When we stratified studies for the predefined factors such as dosage, and age, no significant effects of the intervention on triglycerides, LDL-C, and HDL-C levels were found. This meta-analysis demonstrated that L-carnitine administration significantly reduced triglycerides, total cholesterol and LDL-cholesterol levels, and significantly increased HDL-cholesterol levels in the pooled analyses, but did not affect VLDL-cholesterol levels; however, these findings were not confirmed in our subgroup analyses by participant's health conditions, age, dosage of L-carnitine, duration of study, sample size, and study location.

Fathizadeh H ，Milajerdi A ，Reiner Ž ，Kolahdooz F ，Chamani M ，Amirani E ，Asemi Z ... -  《-》