Vitamin D and non-alcoholic fatty liver disease: a meta-analysis of randomized controlled trials.
Study Goal
The researchers aimed to evaluate whether vitamin D supplementation has beneficial effects on alanine aminotransferase (ALT) and other metabolic markers in patients with non-alcoholic fatty liver disease (NAFLD).
Results Summary
The study found that vitamin D supplementation marginally reduced ALT levels (-0.18; 95%CI: -0.39, 0.04) and significantly improved glycemic control and insulin sensitivity, but did not significantly affect AST, TC, HDL-C, or LDL-C levels.
Population
544 subjects with non-alcoholic fatty liver disease (NAFLD).
Effective Dosage
Not specified in the abstract.
Duration
Not specified in the abstract.
Interactions
None mentioned.
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
supplemental vitamin D | decrease | serum/plasma fasting glucose | NAFLD subjects | -0.22; 95%CI: -0.39, -0.04 | significantly reduced | #1 |
supplemental vitamin D | decrease | insulin | NAFLD subjects | -0.68; 95%CI: -1.22, -0.14 | significantly reduced | #2 |
supplemental vitamin D | decrease | HOMA-IR | NAFLD subjects | -1.32; 95%CI: -2.30, -0.34 | significantly reduced | #3 |
supplemental vitamin D | decrease | ALT | NAFLD subjects | -0.18; 95%CI: -0.39, 0.04 | marginally reduced | #4 |
supplemental vitamin D | decrease | TAG | NAFLD subjects | -10.38; 95%CI: -21.09, 0.34 | marginally reduced | #5 |
supplemental vitamin D | no change | AST | NAFLD subjects | - | did not support that was beneficial for | #6 |
supplemental vitamin D | no change | TC | NAFLD subjects | - | did not support that was beneficial for | #7 |
supplemental vitamin D | no change | HDL-C | NAFLD subjects | - | did not support that was beneficial for | #8 |
supplemental vitamin D | no change | LDL-C | NAFLD subjects | - | did not support that was beneficial for | #9 |
supplemental vitamin D | decrease | glycemic control | NAFLD patients | - | has favorable effects on | #10 |
supplemental vitamin D | increase | insulin sensitivity | NAFLD patients | - | has favorable effects on | #11 |
The results of randomized controlled trials (RCTs) investigating supplemental vitamin D on aminotransferases and cardio-metabolic risk factors in subjects with non-alcoholic fatty liver disease (NAFLD) have been inconsistent. The present study aimed to quantitatively evaluate whether supplementation with vitamin D has beneficial effects in treatment of NAFLD. A systematical literature search was performed with Cochrane Library, PubMed, Scopus databases and Web of Science up to June 2020. The mean changes in alanine aminotransferase (ALT), aspartate aminotransferase (AST), fasting glucose, insulin, homeostasis model assessment of insulin resistance (HOMA-IR), total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), and triglyceride (TAG) were calculated as standard mean difference (SMD) using a random-effects model. Pre-specified subgroup and univariate meta-regression analyses were performed to identify the sources of heterogeneity. Ten trials with a total of 544 NAFLD subjects were included for data synthesis. The summary estimates indicated that supplemental vitamin D significantly reduced the levels of serum/plasma fasting glucose (-0.22; 95%CI: -0.39, -0.04), insulin (-0.68; 95%CI: -1.22, -0.14) and HOMA-IR (-1.32; 95%CI: -2.30, -0.34), and marginally reduced the ALT (-0.18; 95%CI: -0.39, 0.04) and TAG (-10.38; 95%CI: -21.09, 0.34) levels. However, the pooled effect did not support that supplemental vitamin D was beneficial for concentrations of AST, TC, HDL-C and LDL-C. The present study provides substantial evidence that supplemental vitamin D has favorable effects on glycemic control and insulin sensitivity in NAFLD patients. Vitamin D could be as an adjuvant pharmacotherapy of NAFLD.