Effect of vitamin E in non-alcoholic fatty liver disease: a systematic review and meta-analysis of randomised controlled trials

Abstract

The efficacy of vitamin E among patients with non-alcoholic fatty liver disease (NAFLD) is unclear. The current qualitative and quantitative analyses aimed to ascertain the efficacy of vitamin E on clinical outcomes of patients with NAFLD. A systematic search of randomised controlled trials (RCTs) was performed using databases (PubMed, ProQuest, Scopus, EBSCOhost and Ovid) from inception to July 2018. Trials meeting the inclusion criteria were subjected to quality assessment using the Jadad Scoring. All trials meeting the prerequisites information for meta-analysis were subjected to quantitative synthesis of results. Nine RCTs (five in adults and four in children) were included. Four of the five RCTs on adults demonstrated significant improvements in alanine transaminase and other liver function surrogates in patients with NAFLD. On the other hand, only one of the four RCTs conducted on children showed significant improvements in liver functions with the use of vitamin E. Although quantitative synthesis of available data revealed insignificant differences between vitamin E and placebo, still the use of vitamin E improves the level of alanine transaminase and aspartate transaminase by −1.96 and −0.59, with heterogeneity of I2=67% and I2=0%, respectively. Adjuvant vitamin E therapy provides significant biochemical and histological improvements in adult patients with NAFLD, while paediatric patients showed insignificant efficacy compared with placebo. Lifestyle interventions along with vitamin E can provide much better results. Data, including the impact of vitamin E on hepatic histology, are still lacking. Moreover, the short duration of trials limits the conclusion on the safety and efficacy of proposed treatments.