Effect of oral citrulline supplementation on whole body protein metabolism in adult patients with short bowel syndrome: A pilot, randomized, double-blind, cross-over study

As citrulline is produced by small intestine, plasma citrulline concentration is decreased and may become essential in patients with short bowel syndrome (SBS). In a rat model of SBS, citrulline supplementation enhanced muscle protein synthesis. The aim of the study was to determine whether citrulline impacts whole body protein metabolism in patients with SBS. Nine adults with non-malignant SBS (residual small bowel 90 ± 48 cm; mean ± SD) who were in near-normal nutritional status without any artificial nutrition, were recruited long after surgery. They received 7-day oral supplementation with citrulline (0.18 g/kg/day), or an iso-nitrogenous placebo in a randomized, double-blind, cross-over design with a 13-day wash-out between regimens, and an intravenous 5-h infusion of L-[1–13C]-leucine in the postabsorptive state to assess protein metabolism after each regimen. Plasma citrulline concentration rose 17-fold (25 ± 9 vs. 384 ± 95 μmol/L) and plasma arginine 3-fold after oral citrulline supplementation (both p