Post by deborah on May 13, 2019 15:34:36 GMT
Effect of Vitamin D on Non-Alcoholic Fatty Liver Disease: A Systematic Review of Randomized Controlled Clinical Trials
Abstract
New evidence suggests that low serum Vitamin D may cause nonalcoholic fatty liver disease (NAFLD).
Hypovitaminosis D is associated with the severity and incidence of NAFLD.
The objective of this study was to conduct a systematic review on randomized controlled trials (RCTs) assessing the effect of Vitamin D on serum metabolic profile among NAFLD patients. Databases including PubMed, Institute for Scientific Information Web of Science, Scopus, and Google Scholar were searched up to November 2016. RCTs which studied Vitamin D effect on metabolic profiles and liver function, and conducted among adults were included. Six articles were eligible to be considered in this systematic review. According to the result, Vitamin D supplementation might improve lipid profile and inflammatory mediators when compared with placebo. No article indicated significant effect of Vitamin D on liver enzymes except one article which revealed that Vitamin D together with calcium carbonate can reduce liver enzymes. Vitamin D supplementation may not improve anthropometric measures and glycemic index variables among patients with NAFLD. Vitamin D supplement might improve NAFLD symptoms, especially inflammatory mediators. More RCTs in different parts of world with different forms and doses of Vitamin D are necessary.
Introduction
Nonalcoholic fatty liver disease (NAFLD) is considered as the most common cause of liver disease.[1] NAFLD has a broad spectrum of diseases that vary from nonalcoholic steatohepatitis (NASH) to fibrosis and cirrhosis.[2] The prevalence of NAFLD in the general population is 20%, but in patients with type 2 diabetes, it is 90%.[2,3] During the last decades, different pharmacological and nutraceutical interventions for the treatment of NAFLD were assessed, but none indicated significant results; therefore, no medically approved medicine for NAFLD is available.[4] Due to the fact that obesity causes inflammation and insulin resistance which are the main causes of NAFLD, weight reduction is considered as a standard treatment for this disease.[5]
New evidence suggested that low serum Vitamin D may cause metabolic diseases[6,7,8] and NAFLD.[9] Hypovitaminosis D is associated with the severity[9] and incidence of NAFLD among patients who have normal liver enzymes.[10] According to the result of a recent meta-analysis, patients with NAFLD have a 26% additional risk for Vitamin D deficiency as compared to controls.[11]
Vitamin D through Vitamin D receptor (VDR) can affect the liver. VDR exists in hepatic cells, and its expression can reduce inflammation in chronic hepatic diseases.[12] In vitro studies indicated that VDR by the enhancement of glucose transporter-4 muscular expression and modulation of free fatty acids (FFAs) increased insulin sensitivity.[13] Vitamin D also has antifibrotic, antiproliferative, and anti-inflammatory effects on the liver.[14] Furthermore, Vitamin D can reduce the concentration of cytokeratin 18 apoptotic fragment M30 as a marker of hepatic damage.[15,16,17,18]
Moreover, some articles indicated that low concentration of serum 25-hydroxyvitamin D (25(OH)D) enhances the body, which is a risk factor for hepatic steatosis.[2] Animal studies have shown that high level of calcium can reduce body weight through the reduction of fatty acid synthesize and the enhancement of lipolysis.
All these effects make Vitamin D a promising supplement for the treatment of NAFLD by the inhibition of lipid accumulation in liver cells. Studies that assessed the effects of Vitamin D on NAFLD have controversies. Therefore, through a systematic review, the authors proposed to assess the effectiveness of Vitamin D in the treatment of NAFLD.
www.ncbi.nlm.nih.gov/pmc/articles/PMC6360993/
Abstract
New evidence suggests that low serum Vitamin D may cause nonalcoholic fatty liver disease (NAFLD).
Hypovitaminosis D is associated with the severity and incidence of NAFLD.
The objective of this study was to conduct a systematic review on randomized controlled trials (RCTs) assessing the effect of Vitamin D on serum metabolic profile among NAFLD patients. Databases including PubMed, Institute for Scientific Information Web of Science, Scopus, and Google Scholar were searched up to November 2016. RCTs which studied Vitamin D effect on metabolic profiles and liver function, and conducted among adults were included. Six articles were eligible to be considered in this systematic review. According to the result, Vitamin D supplementation might improve lipid profile and inflammatory mediators when compared with placebo. No article indicated significant effect of Vitamin D on liver enzymes except one article which revealed that Vitamin D together with calcium carbonate can reduce liver enzymes. Vitamin D supplementation may not improve anthropometric measures and glycemic index variables among patients with NAFLD. Vitamin D supplement might improve NAFLD symptoms, especially inflammatory mediators. More RCTs in different parts of world with different forms and doses of Vitamin D are necessary.
Introduction
Nonalcoholic fatty liver disease (NAFLD) is considered as the most common cause of liver disease.[1] NAFLD has a broad spectrum of diseases that vary from nonalcoholic steatohepatitis (NASH) to fibrosis and cirrhosis.[2] The prevalence of NAFLD in the general population is 20%, but in patients with type 2 diabetes, it is 90%.[2,3] During the last decades, different pharmacological and nutraceutical interventions for the treatment of NAFLD were assessed, but none indicated significant results; therefore, no medically approved medicine for NAFLD is available.[4] Due to the fact that obesity causes inflammation and insulin resistance which are the main causes of NAFLD, weight reduction is considered as a standard treatment for this disease.[5]
New evidence suggested that low serum Vitamin D may cause metabolic diseases[6,7,8] and NAFLD.[9] Hypovitaminosis D is associated with the severity[9] and incidence of NAFLD among patients who have normal liver enzymes.[10] According to the result of a recent meta-analysis, patients with NAFLD have a 26% additional risk for Vitamin D deficiency as compared to controls.[11]
Vitamin D through Vitamin D receptor (VDR) can affect the liver. VDR exists in hepatic cells, and its expression can reduce inflammation in chronic hepatic diseases.[12] In vitro studies indicated that VDR by the enhancement of glucose transporter-4 muscular expression and modulation of free fatty acids (FFAs) increased insulin sensitivity.[13] Vitamin D also has antifibrotic, antiproliferative, and anti-inflammatory effects on the liver.[14] Furthermore, Vitamin D can reduce the concentration of cytokeratin 18 apoptotic fragment M30 as a marker of hepatic damage.[15,16,17,18]
Moreover, some articles indicated that low concentration of serum 25-hydroxyvitamin D (25(OH)D) enhances the body, which is a risk factor for hepatic steatosis.[2] Animal studies have shown that high level of calcium can reduce body weight through the reduction of fatty acid synthesize and the enhancement of lipolysis.
All these effects make Vitamin D a promising supplement for the treatment of NAFLD by the inhibition of lipid accumulation in liver cells. Studies that assessed the effects of Vitamin D on NAFLD have controversies. Therefore, through a systematic review, the authors proposed to assess the effectiveness of Vitamin D in the treatment of NAFLD.
www.ncbi.nlm.nih.gov/pmc/articles/PMC6360993/