Grains or Veins: Is Enteral Nutrition Really Better Than Parenteral Nutrition? A Look at the Evidence

Background: Enteral nutrition is said to be better than parenteral nutrition for providing nutrition support to humans. Purpose: To assess the literature documenting the assertions that enteral nutrition is superior to parenteral nutrition with respect to cost, safety, physiology, intestinal structure and function, bacterial translocation, and outcome. Data identification: Sources included MEDLINE search, personal files, and references from human comparative studies of enteral vs parenteral nutrition. Study selection: The goal was to include all human studies directly addressing questions of comparative efficacy of enteral and parenteral nutrition. Emphasis was given to prospective randomized controlled studies where available. Retrospective comparisons were not included. Data extraction: An attempt was made to briefly summarize methodology and findings of relevant studies. No general attempt was made to assess quality of individual studies. Results of data synthesis: Enteral nutrition appears to be less expensive than parenteral nutrition, but new economic analyses are needed given the newer aggressive access techniques for enteral nutrition. Enteral nutrition is associated with meaningful morbidity and mortality. The little comparative data existent suggest no differences in safety. Comparative studies of physiology and metabolism as well as comparative and noncomparative studies of intestinal function and structure do not support putative advantages of enteral nutrition. There is no evidence that enteral nutrition prevents bacterial translocation in humans. Enteral nutrition probably reduces septic morbidity compared with parenteral nutrition in abdominal trauma. Otherwise, there is no evidence that enteral nutrition consistently improves patient outcome compared with parenteral nutrition. Conclusions: With the exception of decreased cost and probable reduced septic morbidity in acute abdominal trauma, the available literature does not support the thesis that enteral nutrition is better than parenteral nutrition in humans. (Journal of Parenteral and Enteral Nutrition 22:167-182, 1998)