A narrative review on effects of vitamin D on main risk factors and severity of Non-Alcoholic Fatty Liver Disease.

The global prevalence of Non-alcoholic fatty liver disease (NAFLD) is increasing rapidly. Many studies have been conducted on the treatment of NAFLD; nevertheless, there is still no approved drug treatment for this disease. Although the pathogenesis of NAFLD is not fully understood, but inflammation, insulin resistance, oxidative stress, obesity and dyslipidemia are among the main causes. Epidemiological studies have shown that hypovitaminosis D is associated with these factors causing NAFLD. In addition, rate of Vitamin D deficiency has been shown to be directly related to the severity of NAFLD. Accordingly, it is believed that vitamin D may help to treatment of NAFLD by improving the above-mentioned risk factors. The purpose of this review is to survey the recent advances in the field of Vitamin D efficacy on risk factors and the severity of NAFLD based on existing evidence, especially the clinical efficiency of vitamin D supplementation in patients with NAFLD.