The effect of Alpha-lipoic acid supplementation on endothelial function: A systematic review and meta-analysis

There is evidence that alpha-lipoic acid (ALA) supplementation plays an important role in preventing cardiovascular diseases. However, its effect, specifically, on endothelial function (EF) is unclear. Therefore, this systematic review and meta-analysis aimed to evaluate the effects of ALA supplementation on EF. Databases including PubMed/Medline, Scopus, and ISI Web of Science were searched to identify eligible publications from inception up to April 2020. Randomized controlled trials assessing the effect of ALA supplementation on flow-mediated dilation (FMD) levels in adults were included. The pooled results were obtained using the random-effects model and are expressed as weighted mean differences (WMD) with 95% confidence intervals (CI). Five studies including six effect sizes and 300 participants were included. ALA supplementation significantly increased FMD levels by 2.36% (95% CI: 1.21-3.51; p < .001), compared with the control. Subgroup analyses suggested that the effects of ALA on FMD could be changed by age and health status of the participants. Dose-response analysis also showed that ALA dosage had a significant non-linear effect on FMD levels. The results showed that ALA supplementation appears to improve the EF. However, the role of ALA supplementation in improving other biomarkers of EF requires further research.