Effects of Citrulline on Non-alcoholic Fatty Liver Disease: A Randomized-controlled Clinical Trial

Background and Objectives: Citrulline (cit.) is a non-essential amino acid derived from watermelon, which affects improving glucose tolerance and lipid and energy metabolisms. The aim of this study was to investigate effects of citrulline supplementation on non-alcoholic fatty liver.  Materials & Methods: In this randomized clinical trial, 50 patients with NAFLD were randomly assigned to receive either cit. or placebo. Patients received four capsules of 500 mg (cit. or placebo) daily. Both groups were advised to follow energy-balanced diets and physical activities. Liver enzymes and hepatic steatosis and fibrosis were assessed at the baseline and end of the study. Paired t-test, t-test and chi-2 were used for data analysis. Results: No significant differences were observed for the monitored variables between the two groups at the baseline. After treatment, the experimental group consuming cit. supplementation showed a statistically significant decrease for ALT and hepatic steatosis, compared to control group (P<0.05). Furthermore, serum levels of AST and GGT and also hepatic fibrosis showed no significant differences between the two groups (P≥0.05). Conclusion: Results of this study showed that citrulline could decrease ALT and degrees of steatosis in cit. group with no significant differences between the two groups. In cit. group, liver enzymes of alanine aminotransferase  decreased (7.26 IU/L), compared to control group (7.19 IU/L). Moreover, citrulline demonstrated no significant effects on hepatic fibrosis and other liver enzymes. To investigated effects of citrulline on liver, further studies with various doses and periods of time are necessary.