The effect of L-carnitine supplementation on lipid profile in adults: an umbrella meta-analysis on interventional meta-analyses.

Introduction: Previous meta-analyses investigating the therapeutic effects of L-carnitine on lipid profiles have demonstrated inconsistent results. The present umbrella meta-analysis aimed to investigate the impact of efficacy of L-carnitine on lipid profiles in adults. Methods: Databases including PubMed, Scopus, and Embase, Web of Science, and Google Scholar were searched up to June 2023. Meta-analysis was performed using a random-effects model. Results: Our results from thirteen meta-analyses indicated that L-carnitine supplementation significantly total cholesterol (TC) (ES = -1.05 mg/dL, 95% CI: -1.71, -0.39; p = 0.002), triglycerides (TG) (ES = -2.51 mg/dL; 95% CI: -3.62, -1.39, p < 0.001), and low-density lipoprotein-cholesterol (LDL-C) (ES = -4.81 mg/dL; 95% CI: -6.04, -3.59; p < 0.001). It also increased high-density lipoprotein-cholesterol (HDL-C) (ES: 0.66 mg/dL, 95% CI: 0.20, 1.12, p = 0.005) levels. Conclusion: The present umbrella meta-analysis suggests supplementation with L-carnitine in a dosage of more than 2 g/day can improve lipid profile. Thus, L-carnitine supplementation can be recommended as an adjuvant anti-hyperlipidemic agent.

Vitamin D protects against depression: Evidence from an umbrella meta-analysis on interventional and observational meta-analyses.

Meta-analyses of interventional and observational studies investigating the efficacy and the relationship between vitamin D and depression provided inconsistent results. The current umbrella meta-analysis was conducted to assess the available evidence and provide a conclusive outcome in this regard. The following international databases were systematically searched till March 2022: PubMed, Scopus, Embase, Web of Science, and Google Scholar. Random-effects model was carried out to calculate the pooled point estimates and their respective 95 % confidence intervals (CI). Ten meta-analyses of randomised controlled trials (RCTs) revealed significant reduction in depression symptoms comparing participants on vitmain D supplements to those on placebo (Pooled standardised mean difference: - 0.40; 95 % CI: - 0.60, - 0.21, p < 0.01: I2 = 89.1 %, p < 0.01). Four meta-analyses of cohort studies (with one having two subgroups) revealed that participants with lower levels of serum vitamin D were at increased odds of depression than those with higher levels of serum vitamin D (Pooled odds ratio: 1.60; 95 % CI: 1.08, 2.36, p < 0.01; I2 = 91.3 %, p < 0.01). The present umbrella meta-analysis confirms the potential benefits of vitamin D supplementation and higher serum vitamin D levels in reducing the development and symptoms of depression.

Cinnamon, an effective anti-obesity agent: Evidence from an umbrella meta-analysis.

The evidence provided by meta-analyses on the beneficial impacts of cinnamon supplementation on anthropometric indices are still conflicting. Present study's aim was to evaluate the effects of cinnamon on obesity indices by an umbrella meta-analysis. The electronic databases including Web of Science, PubMed, EMBASE, Scopus were systematically searched up to March 2021. Data for the effects of cinnamon on anthropometric indices were collected from the meta-analyses. An umbrella meta-analysis was carried out using a random-effects model. The pooled effects of 7 meta-analyses showed that cinnamon supplementation significantly reduced body weight (ES: -0.67 kg; 95% CI: -0.99, -0.35, p Ë‚ .001), body mass index (ES: -0.45 kg/m2 ; 95% CI: -0.57, -0.33, p Ë‚ .001) in comparison to control group. However, the effects of cinnamon on waist circumference (ES: -1.05 cm; 95% CI: -2.26, 0.15, p = .087) were not considerable. According to results, cinnamon could be suggested as a complementary weight loss agent. Favorable results were obtained at a dose of ≥3 g/day. In this study, a comprehensive study was performed on meta-analyses performed on the effect of cinnamon on anthropometric indices. This study could be considered as a final conclusion about the effect of cinnamon on anthropometric indices. The results of this study showed that supplementation with cinnamon significantly reduces BMI and body weight. The impacts were greater in doses of ≥3 g/day and in PCOS patients. PRACTICAL APPLICATIONS: In this study, a comprehensive study was performed on meta-analyses performed on the effect of cinnamon on anthropometric indices. This study could be considered as a final conclusion about the effect of cinnamon on anthropometric indices. The results of this study showed that supplementation with cinnamon significantly reduces BMI and body weight. The impacts were greater in doses of ≥3 g/day and in PCOS patients.

Saffron, as an adjunct therapy, contributes to relieve depression symptoms: An umbrella meta-analysis.

BACKGROUND: Saffron is a traditional herbal medicine that has been used to treat various ailments such as depressive mood. However, the findings of several meta-analyses regarding anti-depressive properties of saffron (Crocus sativus L.) are controversial. The current umbrella meta-analysis was carried out to determine the magnitude and direction of saffron administration on depression. METHODS: Relevant studies were searched in international databases including PubMed, Scopus, EMBASE, Web of Science, and Cochrane Central Library up to June 2021. Meta-analysis studies investigating the effects of saffron on depression were considered to include in the study. Random-effects model was used to perform the meta-analysis. Additional analyses including subgroup and sensitivity analyses were carried out. RESULTS: Overall, 7 meta-analyses were included in the study. The results demonstrated that the consumption of saffron resulted in a significant reduction in BDI scores (ES: -3.87; 95% CI: -5.27, -2.46). However, saffron did not change the HAMD scores (ES: -2.10; 95% CI: -5.05, 0.86, p = 0.164) and mixed scores (HAM-D/BDI/DASS) (ES: 0.02; 95% CI: -0.39, 0.43,p = 0.941). CONCLUSION: Present umbrella meta-analysis demonstrated that saffron intake might contribute to alleviation of depression disorder, however, it cannot be considered as a single therapeutic approach to treat depression.

Flaxseed Oil Supplementation Augments Antioxidant Capacity and Alleviates Oxidative Stress: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

OBJECTIVE: Studies have reported controversial findings regarding the flaxseed oil effect on antioxidant status biomarkers. The present meta-analysis aimed to determine the impact of flaxseed oil on the serum level of biomarkers of oxidative stress. METHODS: A systematic search was conducted up to November 2020 on PubMed, Embase, Web of Science, Scopus, and Cochrane Central Library. Random-effects model was employed to perform meta-analysis. Subgroup analysis was carried out to determine the effect across different ranges of dosages and durations. RESULTS: Eight trials were included with a total sample size of 429 individuals with a mean age range of 25 to 70 years. The results indicated that flaxseed oil supplementation led to a significant decrease in malondialdehyde (MDA) levels (SMD: -0.52 µmol/L; 95% CI: -0.89, -0.15; P=0.006, I 2 = 71.3, P < 0.001) and increase in total antioxidant capacity (TAC) levels (WMD: 82.84 mmol/L; 95% CI: 19.80, 145.87; P=0.006, I 2 = 92.7, P < 0.001). No significant effect was observed on glutathione (GSH). CONCLUSION: Our findings revealed that flaxseed oil supplementation might play a beneficial role in the reinforcement of the antioxidant defense system and amelioration of oxidative stress in adults.