Objective: Evidence indicates that NAFLD patients are vitamin D deficient. Vitamin D has new roles in lipid and glucose metabolism. The aim of this study was to examine the effects of calcitriol supplementation on the NAFLD progression based on liver lipid accumulation, serum lipid profile and insulin resistance.
Methods: We randomly assigned 73 patients with NAFLD-confirmed by ultra-sonography to 12 weeks of treatment with hypocaloric diet (reduction of 500 kcal per day) plus 25 µg of calcitriol supplement or a hypocaloric diet plus placebo. Before and after treatment, we assessed anthropometric parameters, grade of fatty liver, serum lipoproteins, liver enzymes and insulin level.
Result: Baseline variables were not significantly different between groups. A statistically significant reduction in anthropometric measures was observed over the 12 weeks in both groups. However, no significant differences were seen between groups after intervention. Compared with the placebo, reductions in triglyceride and an increase in HDL cholesterol were seen over the 12 weeks of intervention in the calcitriol group (P = 0.002 and P = 0.004). AST level was decreased in the calcitriol group (-4.2 ± 4.3 µmol/L, P < 0.001), but increased in the placebo group (12.6 ± 6.1 µmol/L, P = 0.02) after 12 weeks. Reductions in mean difference of ALT, insulin and HOMA were significantly higher in the calcitriol than placebo group (P = 0.01, P = 0.007 and 0.01).
Conclusions: Calcitriol supplementation combined with weight loss diet showed no significant effects on anthropometric measures in NAFLD patients. However, it may have positive effects on lipid profile, liver enzyme tests and insulin sensitivity during a weight-loss program.