Effect of Oral and parenteral routes of vitamin D supplementation on serum 25(OH) vitamin D levels in patients with non-alcoholic fatty liver disease

Background: Due to the interruption of the EHC pathway in NAFLD patients, we hypothesized that parenteral vitamin D supplementation is superior to oral in vitamin D insufficient patients with NAFLD. Therefore, this study aimed to compare the efficacy of oral and parenteral routes of vitamin D supplementation on serum 25(OH) vitamin D levels in patients with NAFLD. Methods: In this prospective randomized trial, 66 NAFLD cases with vitamin D deficiency were studied. For 33 cases, oral vitamin D was supplemented, whereas the other 33 patients were given an intramuscular injection of vitamin D. Laboratory tests and liver ultrasound were performed at the beginning and the end of the trial for each subject. Results: Regardless of the drug administration route, at the end of this trial the mean of serum 25-hydroxy vitamin D level increased from 8.74±2.47 to 33.16±17.61 (P=0.00), and the mean±SD for serum triglyceride decreased from 191.46±92.79 to 166.00±68.30 (P=0.02), both were statistically significant. Liver ultrasound reported statistically significant changes in the grade of fatty liver disease (P=0.003). In the comparison between the two groups, serum 25-hydroxy vitamin D level changes were not statistically significant (P=0.788). Conclusion: The intramuscular method of supplementation was not better than the oral route in improving serum 25(OH) vitamin D levels in NAFLD patients. In this study, the impaired EHC and vitamin D absorption inhibitor factors in NAFLD patients did not affect the final result of serum vitamin D levels significantly.