Abstract
Nutritional supplementation has become the standard of care for management of critically ill patients. Traditionally, nutritional support in this patient population was intended to replete substrate deficiencies secondary to stress-induced catabolism. Recognition of the influence of certain nutrients on the immune and inflammatory response of the critically ill has led to the evolution of more sophisticated nutritional strategies and concepts. Administration of immune-enhancing formulas supplemented with a combination of glutamine, arginine, omega-3 fatty acids (omega-3 FA), and nucleotides have been shown in most studies to reduce infectious outcomes. More recently, the separation of nutritional support from the provision of key nutrients has led to a further appreciation of the immunomodulatory and anti-inflammatory benefits of isolated nutrients, such as glutamine and antioxidants. The purpose of this article is to review the molecular mechanisms that are unique to each class of frequently utilized nutrients. A better understanding of the specific molecular targets of immunonutrients will facilitate application of more refined nutritional therapies in critically ill patients.