The effects of vitamin D supplementation on metabolic profiles and liver function in patients with non-alcoholic fatty liver disease: A systematic review and meta-analysis of randomized controlled trials

Abstract

Background: A systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to summarize the evidence on the effect of vitamin D supplementation on metabolic profiles in patients with non-alcoholic fatty liver disease (NAFLD).

Methods: We systematically searched PubMed, EMBASE and five other databases to identify all RCTs investigating the association between vitamin D and NAFLD up until 5 October 2016. Seven RCTs with 452 participants (227 patients and 225 controls) were included in the meta-analysis.

Results: The results showed that vitamin D administration had no beneficial effect on fasting plasma glucose (FPG) (standardized mean difference [SMD]-0.23; 95% confidence interval [CI], -0.88, 0.42), insulin (SMD -1.09; 95% CI, -2.70,0.52) and homeostasis model assessment of insulin resistance (HOMA-IR) (SMD -1.89; 95% CI, -3.88,0.09). Vitamin D supplementation also had no effect on lipid profiles including triglycerides (SMD -0.36; 95% CI, -1.77, 1.04), and total-cholesterol (SMD -0.46; 95% CI: -1.3, 0.39), as well as on aspartate transaminase (AST) (SMD -0.53; 95% CI, -1.11, 0.05), alanine aminotransferase (ALT) (SMD -0.66; 95% CI, -1.43,0.11), and body mass index (BMI) (SMD -0.25; 95% CI, -0.76,0.27).

Conclusions: Vitamin D supplementation had no effect on FPG, insulin, HOMA-IR, triglycerides, total-, LDL-cholesterol, AST, ALT, and BMI.

Keywords: Liver function; Meta-analysis; Metabolic profiles; Non-alcoholic fatty liver disease; Vitamin D supplement.