The effects of vitamin C supplementation on glycemic control in patients with type 2 diabetes: A systematic review and meta-analysis.

BACKGROUND AND AIM: It has been suggested that taking vitamin C supplements may improve glycemic control in patients with type 2 diabetes mellitus (T2DM). However, there has not been a thorough evaluation of the actual impact or certainty of the findings. This systematic review and meta-analysis was conducted to determine the effect of vitamin C supplementation on glycemic profile in T2DM patients. METHODS: A systematic search was performed across online databases including Scopus, Web of Science, and PubMed/Medline to identify relevant randomized controlled trials (RCTs) published until July 2022. A random-effects model was applied for the meta-analysis. RESULTS: The present meta-analysis included a total of 22 RCTs with 1447 patients diagnosed with T2DM.A pooled analysis revealed a significant decrease in levels of serum hemoglobin A1c (HbA1c), fasting insulin, and fasting blood glucose (FBG) in vitamin C-treated T2DM patients compared with their untreated counterparts. The dose-response evaluation displayed a substantial linear association between the intervention duration and changes in serum HbA1c levels. However, the analysis did not demonstrate any significant effect of vitamin C on serum values of homeostasis model assessment of insulin resistance(HOMA-IR) in diabetic patients. Subgroup analyses indicated that high-dose vitamin C administration (≥1000 mg/d) considerably decreased serum HOMA-IR levels. CONCLUSION: These findings suggest that long-term (≥12 weeks) and high-dose vitamin C supplementation (≥1000 mg/d) may ameliorate glycemic profile in T2DM patients. However, additional high-quality RCTs are necessary to validate these results.

The impact of Emblica Officinalis (Amla) on lipid profile, glucose, and C-reactive protein: A systematic review and meta-analysis of randomized controlled trials.

BACKGROUND AND AIMS: Emblica Officinalis (Amla) is a plant often utilized in traditional medicine due to its purported anti-inflammatory, antioxidant, hypoglycemic, and hypolipidemic properties. However, current evidence regarding its potential for preventing and treating metabolic abnormalities associated with chronic diseases remains unclear. METHODS: This systematic review and meta-analysis aimed to examine the effects of Amla supplementation on lipid profile, glucose, and C-reactive protein (CRP) concentrations in adults. We completed a systematic search (current as of December 2022) of all available randomized controlled trials (RCTs) in the database including ISI Web of Science, PubMed, Scopus, and Embase. Any effect's mean difference (MD) was calculated using a random-effects model. Weighted mean difference (WMD) and 95% confidence intervals (CIs) were calculated also calculated using a random-effects model. RESULTS: Five RTCs were included in the meta-analysis. Following Amla supplementation, pooled results showed a significant reduction in CRP (p = 0.002), fasting blood glucose (FBG) (p < 0.001), low-density lipoprotein cholesterol (LDL-c) (p < 0.001), total cholesterol (TC) (p < 0.001), and serum triglyceride (TG) (p < 0.001) concentrations as well as an increase in high-density lipoprotein cholesterol (HDL-c) (p < 0.001). The baseline concentration of biochemical indicators was used for subgroup analysis. CONCLUSION: Amla supplementation shows promise for improving metabolic parameters in adults. In general, the populations included in the analysis were generally 40-58 years with an average BMI of 25.5 and a length of intervention ranging from 3 to 12 weeks. Thus additional investigations are warranted to confirm and expand the findings presented herein.

The effects of conjugated linoleic acid supplementation on lipid profile in adults: A systematic review and dose-response meta-analysis.

Background: The findings of trials investigating the effect of conjugated linoleic acid (CLA) administration on lipid profile are controversial. This meta-analysis of randomized controlled trials (RCTs) was performed to explore the effects of CLA supplementation on lipid profile. Methods: Two authors independently searched electronic databases including PubMed, Web of Science, and Scopus until March 2022, in order to find relevant RCTs. The random effects model was used to evaluate the mean and standard deviation. Results: In total, 56 RCTs with 73 effect sizes met the inclusion criteria and were eligible for the meta-analysis. CLA supplementation significantly alter triglycerides (TG) (WMD: 1.76; 95% CI: -1.65, 5.19), total cholesterols (TC) (WMD: 0.86; 95% CI: -0.42, 2.26), low-density lipoprotein cholesterols (LDL-C) (WMD: 0.49; 95% CI: -0.75, 2.74), apolipoprotein A (WMD: -3.15; 95% CI: -16.12, 9.81), and apolipoprotein B (WMD: -0.73; 95% CI: -9.87, 8.41) concentrations. However, CLA supplementation significantly increased the density lipoprotein cholesterol (HDL-C) (WMD: -0.40; 95% CI: -0.72, -0.07) concentrations. Conclusion: CLA supplementation significantly improved HDL-C concentrations, however, increased concentrations of TG, TC, LDL-C, apolipoprotein A, and apolipoprotein B. Systematic review registration: https://www.crd.york.ac.uk/prospero/#recordDetails, identifier: CRD42022331100.

The effects of conjugated linoleic acid supplementation on liver function enzymes and malondialdehyde in adults: A GRADE-assessed systematic review and dose-response meta-analysis.

BACKGROUND: Previous research reported inconsistent findings regarding the effects of conjugated linoleic acid (CLA) supplementation on liver enzymes. This systematic review and meta-analysis was conducted to summarize data from available randomized clinical trials (RCTs) on the effect of CLA supplementation on alanine aminotransferase (ALT), aspartate aminotransferase (AST) and malondialdehyde (MDA) in adults. METHODS: Google Scholar, PubMed, Web of Science, Scopus, and the Cochrane databases were investigated to identify relevant articles up to July 2022. The weighted mean differences (WMD) and 95 % confidence intervals (CI) were calculated via a random-effects model to evaluate the effect size. Between studies, heterogeneity was evaluated by the Cochran's Q test and I2. RESULTS: 22 RCTs with 26 effect sizes were included. The effect size for ALT (IU/L), AST (IU/L), and MDA (µmol/L) were 19, 19 and 6 respectively. The pooled analysis demonstrated CLA decreases MDA (p = 0.003). However, ALT and AST levels did not change after CLA supplementation compared with control group. CONCLUSION: CLA supplementation may significantly reduce MDA levels as a marker of oxidative stress. However, supplementing with CLA failed to alter ALT and AST.