Perioperative nutrition prevents the early protein losses in patients submitted to gastrointestinal surgery

Background & aims: The metabolic response to surgery includes a net loss of proteins that influences negatively the clinical evolution of the patients. We investigated the effect of perioperative nutrition on protein metabolism alterations immediately after surgery. Methods: A control group of 21 surgery patients were submitted to conventional perioperative nutritional protocol (18 h of fasting plus low-dose glucose after surgery). An experimental group of eight similar patients was given complete parenteral nutrition during 24 h before and 24 h after surgery. Nitrogen balance, whole body protein synthesis, breakdown, and 3-methylhistidine were determined before surgery and 24 h after surgery. Results: The immediate response to surgery with conventional nutritional management was a net protein loss (−1.023 g prot. kg−1 day−1), caused by an increase in the protein breakdown (137.9% of preoperative values), while the protein synthesis remained unchanged (98.4%). The 3-methylhistidine excretion was not increased in respect to perioperative values, suggesting that the degraded protein was not from muscular origin. The experimental group with perioperative nutrition showed neither protein loss (+0.075 g prot. kg−1 day−1) nor changes in protein synthesis or breakdown vs. preoperative values (96.3% and 88.0%, respectively). Conclusion: Perioperative nutrition prevents the early protein losses after gastrointestinal surgery.