The physiologic response and associated clinical benefits from provision of early enteral nutrition.

Provision of enteral nutrition (EN) to critically ill patients early upon admission to the intensive care unit exerts a beneficial physiologic effect that downregulates systemic immune responses, reduces oxidative stress, and improves patient outcome. Adding specific pharmaconutrient agents to EN in certain patient populations has a synergistic effect, magnifying the degree of this favorable physiologic response. In contrast, failure to provide enteral nutrients creates a physiologic profile that exacerbates oxidative stress and increases the systemic inflammatory response syndrome. Unfortunately, parenteral nutrition (PN) in the form and manner currently provided in North America does not appear to mimic the same physiologic response seen with EN. In the future, use of alternative fuel sources, steps to promote better tolerance of EN, and innovative strategies for delivery of both EN and PN may serve to further enhance the physiologic effect of nutrition therapy and to achieve even greater improvement in patient outcome.