The Effect of Vitamin E Supplementation on Serum Aminotransferases in Non-Alcoholic Fatty Liver Disease (NAFLD): A Systematic Review and Meta-Analysis

Νon-alcoholic fatty liver disease (NAFLD) is a common cause of end-stage liver disease in developed countries. Oxidative stress plays a key role during the course of the disease and vitamin E supplementation has shown to be beneficial due to its antioxidative properties. We aim to investigate the effect of vitamin E supplementation on serum aminotransferase levels in patients with NAFLD. Three electronic databases (MEDLINE, CENTRAL, and Embase) were reviewed for randomized trials that tested vitamin E supplementation versus placebo or no intervention in patients with NAFLD, published until April 2023. A total of 794 patients from 12 randomized trials were included in this meta-analysis. Notwithstanding the studies' heterogeneity and moderate internal validity in certain cases, among studies testing vitamin E supplementation at 400 IU/day and above, the values of alanine aminotransferase (ALT) were reduced compared with placebo or no intervention [ALT Mean Difference (MD) = -6.99 IU/L, 95% CI (-9.63, -4.35), for studies conducted in Asian countries and MD = -9.57 IU/L, 95% CI (-12.20, -6.95) in non-Asian countries]. Regarding aspartate aminotransferase (AST), patients in the experimental group experienced a reduction in serum levels, though smaller in absolute values [AST MD = -4.65 IU/L, 95% CI (-7.44, -1.86) in studies conducted in Asian populations] and of lower precision in non-Asian studies [MD = -5.60 IU/L, 95% CI (-11.48, 0.28)].