Does alpha-lipoic acid affect lipid profile? A meta-analysis and systematic review on randomized controlled trials.

Randomized controlled trials (RCTs) have demonstrated that alpha lipoic acid (ALA) may change lipid profile, but their results are contradictory. The aim of this study is to conduct a meta-analysis to assess the effects of ALA on lipid profile. Electronic databases including ISI web of science, Ovid, PubMed/Medline, SCOPUS, and Google Scholar were searched up to February 2018. RCTs which assessed ALA effects on lipid profile were selected. Weighted mean difference (WMD) and 95% confidence intervals (CIs) in serum lipids concentrations were defined as intervention effects. Random effects model was used to estimate the pooled effect. Heterogeneity was measured by using I2 test. The protocol was registered with PROSPERO (No. CRD42017072365). Database search retrieved 12 articles. Serum total cholesterol (TC) and low density lipoprotein-cholesterol (LDL-) levels were significantly lower in subjects supplemented with alpha-lipoic acid compared with controls (WMD=-10.18 mg/dL; 95% CI: -16.16, -4.20 mg/dL; P = 0.001 and WMD=-9.22 mg/dL; 95% CI: -18.28, -0.16 mg/dL; P = 0.001, respectively), but no significant changes were found for high density lipoprotein-cholesterol (HDL-c) (WMD: 3.02 mg/dL; 95% CI: -0.39, 6.43; P = 0.082). The overall effect of ALA on serum triglyceride did not reveal any significant change, but in subgroup analysis based on health status (diabetic vs. non-diabetic), ALA decreased serum triglyceride levels in both diabetic and non-diabetic groups compared with controls. This meta-analysis revealed that ALA might favorably affect lipid profile especially LDL and TC. However, for confirming these results, more studies particularly among hyperlipidemic patients are needed.