Immunonutrition and outcome

During the last few years, standard enteral preparations have been modified by the addition of immunonutrients, such as arginine, glutamine, omega-3 fatty acids, nucleotides and others. These substrates have been shown to up-regulate host immune response, to control inflammatory response, and to improve nitrogen balance and protein synthesis after injury. The majority of randomised trials focused on clinical outcome have been carried out in GI cancer elective-surgery patients. When immunonutrition was limited to the postoperative period the results are conflicting, probably because the amount of substrates given in the first few days after surgery is not sufficient to promptly reach adequate tissue and for plasma concentration to be active. Better results on outcome were obtained when the provision of the immune-enhancing diet was anticipated before surgery. Recently, it has been reported that in a series of well-nourished patients with GI cancer the simple oral preoperative supplementation of an immune-enhancing diet significantly reduced postoperative infections. In conclusion, based on available data, it seems that outcome of elective, well-nourished GI cancer patients may be improved when immunonutrition is administered pre-operatively.