Comparison of L-arginine and L-citrulline oral supplementation in head trauma ICU patients receiving enteral nutrition: A randomized clinical trial

Objective: This study aimed to compare the effect of L-arginine and L-citrulline supplementation on overall prognosis of critically ill patients. Methods: A total of 105 head trauma ICU patients were randomized to three groups (Arginine, Citrulline, and Control). Patients in the treatment groups took 10 gr per day of oral L-arginine or L-citrulline for 10 days. Demographic characteristics and measurements were recorded. Nitric oxide (NO), prealbumin, pro-oxidant–antioxidant balance (PAB), fasting blood sugar, lipid profile, hepatic enzymes, serum electrolytes, blood urea nitrogen, creatinine, and serum amino acids were measured. Gastrointestinal complications, overall time on a ventilator, length of hospital stay, and 28-day mortality rate were recorded. Results: We observed no significant changes in NO and PAB (p = 0.8, p = 0.1 respectively). There was a significant increase in serum LDL (p = 0.02), which was greater in the control group after 10 days of supplementation. There was a nonsignificant increase in serum L-arginine in all three groups (p = 0.36). However, the change in serum L-arginine was only significant in the citrulline group (p = 0.048). Serum L-citrulline was higher in the citrulline group compared with the arginine group (p = 0.04). Conclusion: L-arginine and L-citrulline supplementation did not increase NO levels beyond that observed in the control group. Also, PAB balance was not different among the intervention groups and the control group. L-arginine and L-citrulline had no significant effects on length of hospital stay, mortality rate, overall time on a ventilator, and other factors evaluated in this study.