Vitamin E supplementation in the treatment on nonalcoholic fatty liver disease (NAFLD): Evidence from an umbrella review of meta‐analysis on randomized controlled trials

Objective We conducted this umbrella review of meta‐analysis on randomized controlled trials to clarify the effects of vitamin E administration on alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma‐glutamyl transferase (GGT), degrees of steatosis and fibrosis in patients with nonalcoholic fatty liver disease (NAFLD). Methods PubMed, MEDLINE, SCOPUS, EMBASE, and Web of Science were searched to identify pertinent articles published up to June 2023. To calculate the overall effect size (ES) and confidence intervals (CI), random‐effects model was used. Results Six meta‐analyses were included in the umbrella review. By pooling ES based on the random‐effects model, we found that vitamin E supplementation significantly decreased ALT (ES −6.47, 95% CI −11.73 to −1.22, P = 0.01), AST (ES −5.35, 95% CI −9.78 to −0.93, P = 0.01), degrees of fibrosis (ES −0.24, 95% CI −0.36 to −0.12, P < 0.001) and steatosis (ES −0.67, 95% CI −0.88 to −0.45, P < 0.001) in NAFLD patients, but had no effect on GGT. In the subgroup analyses, we detected that fibrosis scores notably decreased when vitamin E dosage was >600 IU/day (ES −0.25, 95% CI −0.41 to −0.10, P = 0.002) and when the treatment duration was ≥12 months (ES −0.24, 95% CI −0.37 to −0.12, P < 0.001). Conclusion Vitamin E administration improves ALT, AST, fibrosis, and steatosis in NAFLD subjects. Fibrosis scores were significantly reduced when vitamin E dosage exceeded 600 IU/day or with a treatment duration of at least 12 months.