Effect of vitamin D supplementation on various parameters in patients with non-alcoholic fatty liver disease: An updated meta-analysis

Aim of the study:
The current updated meta-analysis aimed to explore the effects of vitamin D supplementation on various parameters in patients with non-alcoholic fatty liver disease (NAFLD), using the latest trials available.

Material and methods:
PubMed, Embase, and the Cochrane Library were screened for the collection of randomized controlled trials (RCTs) that compared the efficacy of additional vitamin D vs. the placebo group on NAFLD patients in the last 5 years. Trials included were focused on the assessment of anthropometric and biochemical indices.

Results:
Our results revealed that additional vitamin D greatly increased serum 25-hydroxyvitamin D (25(OH)D), and decreased the low-density lipoprotein-cholesterol (LDL-C) levels. However, no significant differences were found in terms of triglyceride (TG), total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), c-glutamyltransferase, fasting blood glucose (FBG), homeostasis model assessment of insulin resistance (HOMA-IR) and Ca²⁺ levels between the supplementation of vitamin D and placebo.

Conclusions:
The present study demonstrated the advantageous impact of supplementary vitamin D on the levels of 25(OH)D and LDL-C in NAFLD patients. However, the results failed to provide evidence for the superiority of additional vitamin D in relation to the concentrations of serum ALP, AST, TC, Ca, g-glutamyl transferase (GGT), TC, FBG, IR and HDL-C.