The efficacy of vitamin E in reducing non-alcoholic fatty liver disease: a systematic review, meta-analysis, and meta-regression

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) affects up to 30% of the population. Clinical trials have questioned the role of vitamin E in the treatment of NAFLD with or without other interventions, with still no firm conclusion reached. This study aims to examine the efficiency of vitamin E alone or combined in the management of NAFLD. METHODS: We performed a systematic literature search on PubMed, Scopus, Embase, Ovid, EBSCO host, Science Direct, Web of Science, and Cochrane CENTRAL for randomized controlled trials (RCTs) of the role of vitamin E alone or combined in NAFLD patients. Extracted manuscripts reported data on biochemical, histological, anthropometric, and metabolic outcomes. Baseline characteristics, settings, dosage, and frequency were also collected. RESEARCH: A total of 1317 patients from 15 RCTs were included in our systematic review and meta-analysis. Vitamin E was superior at improving alanine aminotransferase (ALT), aspartate aminotransferase (AST), NAFLD activity score (NAS), and fibrosis in short- and long-term follow up in the adult population, and long-term follow up in the pediatric population. Improvements in metabolic outcomes were best noticed in pediatric patients. Results from multiple regression models showed a significant association between ALT-AST levels and vitamin E dose. AST levels had a significant effect on NAS, and patients with a baseline AST > 50 IU/l showed more promising results. Changes in weight and body mass index (BMI) were strongly associated with changes in NAS. CONCLUSION: Current evidence affirms that vitamin E – whether alone or combined – improves biochemical and histological outcomes in adults and pediatric patients.