Effects of Arginine and Citrulline supplementation on inflammatory markers in critically ill patients

Background: Citrulline is a nonessential amino acid that is a main precursor of arginine and therefore could be a best alternative for arginine supplementation. The current study aimed to assess the effects of L-arginine and L-citrulline administration on inflammatory factors (C-reactive protein (CRP), interlukine-6 (IL-6)). Methods: A total of 102 patients in 5 trauma intensive care units (ICU) were divided into three groups: Arginine, Citrulline and Control. Patients received 10 g/d L-arginine powder (Arginine Group) or 10 g/d L-citrulline powder (Citrulline Group) for 10 days. Serum level of CRP and IL-6 were determined in all patients before (day 0) and after intervention (day 11). Results: There were significant reduction in IL6 levels only in Citrulline group (P=0.009). Moreover, serum levels of CRP decreased in both experimental group but it was elevated during study period in Control group (mean changes in control group were 0.28 ±19.66, in Citrulline group 11.16 and in arginine group it was 1.12) which was only significant in Citrulline group (P= 0.025). Conclusion: L-citrulline supplementation could have modulatory effects on inflammatory biomarkers.