In recent years, standard nutrition preparations have been modified by adding specific nutrients, such as arginine, ω-3 fatty acids, glutamine, and others, which have been shown to upregulate host immune response, modulate inflammatory response, and improve protein synthesis after surgery. Most randomized trials and several meta-analyses have shown that perioperative administration of enteral arginine, ω-3 fatty acids, and nucleotides (immunonutrition) reduced infection rate and length of hospital stay in patients with upper and lower gastrointestinal (GI) cancer. The most pronounced benefits of immunonutrition were found in subgroups of high-risk and malnourished patients. Promising but not conclusive results have been found in non-GI surgery, especially in head and neck surgery and in cardiac surgery, but larger trials are required before recommending immunonutrition as a routine practice. Conflicting results on the real benefit of parenteral glutamine supplementation in patients undergoing elective major surgery have been published. In conclusion, enteral diets supplemented with specific nutrients significantly improved short-term outcome in patients with cancer undergoing elective GI surgery. Future research should investigate a molecular signaling pathway and identify specific mechanisms of action of immune-enhancing substrates.
Keywords: GI surgery; arginine; glutamine; immunonutrition; postoperative infections; ω-3 fatty acids.