Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Feb 14, 2015; 21(6): 1718-1727
Published online Feb 14, 2015. doi: 10.3748/wjg.v21.i6.1718
Vitamin D: A new player in non-alcoholic fatty liver disease?
Myrto Eliades, Elias Spyrou
Myrto Eliades, Division of Endocrinology, Diabetes and Nutrition, University of Maryland School of Medicine, Baltimore, MD 21201, United States
Elias Spyrou, Department of Internal Medicine, Medstar Washington Hospital Center, Washington, DC 20010, United States
Author contributions: Eliades M and Spyrou E contributed equally to this work.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Correspondence to: Myrto Eliades, MD, Division of Endocrinology, Diabetes and Nutrition, University of Maryland School of Medicine, 660 W. Redwood street, HH 496, Baltimore, MD 21201, United States.
Telephone: +1-410-7066284 Fax: +1-410-7066219
Received: August 27, 2014
Peer-review started: August 28, 2014
First decision: September 15, 2014
Revised: October 25, 2014
Accepted: December 5, 2014
Article in press: December 8, 2014
Published online: February 14, 2015

Vitamin D through its active form 1a-25-dihydroxyvtamin D [1,25(OH)2D] is a secosteroid hormone that plays a key role in mineral metabolism. Recent years have witnessed a significant scientific interest on vitamin D and expanded its actions to include immune modulation, cell differentiation and proliferation and inflammation regulation. As our understanding of the many functions of vitamin D has grown, the presence of vitamin D deficiency has become one of the most prevalent micronutrient deficiencies worldwide. Concomitantly, non-alcoholic fatty liver disease (NAFLD) has become the most common form of chronic liver disease in western countries. NAFLD and vitamin D deficiency often coexist and epidemiologic evidence has shown that both of these conditions share several cardiometabolic risk factors. In this article we provide an overview of the epidemiology and pathophysiology linking NAFLD and vitamin D deficiency, as well as the available evidence on the clinical utility of vitamin D supplementation in NAFLD.

Keywords: Steatohepatitis, Non-alcoholic fatty liver disease, Fatty liver, Vitamin D

Core tip: Non-alcoholic fatty liver disease (NAFLD) is a multifactorial disease and its pathogenesis is closely linked to the metabolic syndrome. Vitamin D deficiency, which also shares similar associations with obesity and sedentary lifestyle, is often found together with NAFLD. As our understanding of the many functions of vitamin D has grown, emerging evidence points to a closely linked and potentially causative relationship between vitamin D deficiency and NAFLD. As such, vitamin D is now emerging as an immunomodulatory and anti-fibrotic agent. However, in order to implement clinical recommendations larger, randomized, placebo-control trials are required to better evaluate the efficacy of vitamin D replacement in NAFLD.