Immunonutrients in critically ill patients: an analysis of the most recent literature

Modulation of inflammatory and immune response to critical illness has been the goal of much research in the last decade and a variety of drugs and nutrients (so called 'immunonutrients') have been tested in experimental models with promising results. Though, in the clinical setting of intensive care, their efficacy have been inconsistently proven, most likely because the effects of each drug may vary in relation to the timing, the dose, the route of administration, the interaction with other nutrients, the severity of illness and many other factors. Though the early studies of the beginning of this century (2000-2009) have shown some clinical benefits, recent multicenter trials (2011-2015) have failed to prove a consistent benefit of immunonutrition in terms of mortality or other clinical endpoints. Reviewing the latest evidence-based documents on this subject (multicenter trials, systematic reviews, meta-analyses and international guidelines), there is no convincing evidence that immunonutrients may be beneficial in the critically ill. Considering that these substances invariably increase the costs of health care and may be unsafe or even harmful in some subgroups, particularly in septic patients, we conclude that routine administration of immune-nutrients (glutamine, arginine, omega-3 fatty acids, selenium, etc.) cannot be currently recommended in the critically ill.