Alpha Lipoic Acid Supplementation and Iron Homeostasis: A Comprehensive Systematic Review and Meta-Analysis of Randomized Controlled Clinical Trials.

Abstract

Background: A growing body of evidence indicates the regulating effects of alpha-lipoic acid on iron metabolism. However, findings from clinical trials are equivocal. This systematic review and meta-analysis aimed to evaluate the quantitative effect of alpha lipoic acid (ALA) supplementation on iron metabolism parameters including serum iron, total iron binding capacity, hemoglobin, and ferritin.

Methodology: Online databases, including PubMed, Scopus, and Web of Science were searched, up to 29 May 2022, to obtain all relevant studies.

Results: A total of 1901 publications were identified in the systematic search; of which, 10 studies with a total of 529 participants were included in this meta-analysis. Pooled analysis of the studies showed no statistically significant effects of ALA on ferritin (weighted mean difference (WMD) = -11.01 ng/mL; 95% CI: -40.07, 18.05 ng/mL; I² = 0.0%, p = 0.670), serum iron (WMD = -0.47 μ/dL; 95% CI: -24.48, 23.54 μ/dL; I² = 94.7%, p < 0.001), hemoglobin (WMD = 0.49 g/dL; 95% CI: -0.54, 1.52 g/dL; I² = 95.7%, p < 0.001), and total iron binding capacity (TIBC) (WMD = 3.95 μ/dL; 95% CI: -21.3, 29.2 μ/dL; I² = 53.1%, p = 0.094). In subgroup analysis, ALA significantly increased hemoglobin in patients with hematological disorders (WMD = 1.23 g/dL; 95% CI: 1.00, 1.45 g/dL; I² = 96.6%, p < 0.001) and in studies with durations longer than 8 weeks (WMD = 1.03 g/dL; 95% CI: 0.82, 1.25 g/dL; I² = 96.5%, p = 0.02).

Conclusion: ALA supplementation had no statistically significant effect on iron-related parameters. Subgroup analysis revealed a significant increasing effect of ALA on hemoglobin in patients with hematological disorders and in studies with durations >8 weeks.