A comparative study of the efficiency of intragastric and parenteral nutrition in man.

Solutions intended for parenteral nutrition were infused at constant rates intravenously and intragastrically in five healthy volunteers. Whole body utilization of nutrients was measured by indirect calorimetry and determination of nitrogen excretion in relation to circulating levels of substrates. Energy balance and urinary nitrogen excretion were the same in all subjects irrespective of whether nutrition was given intravenously or intragastrically. Minor differences in circulating levels of glucagon, alpha-amino nitrogen, and triglycerides were observed but had no impact on the energy and nitrogen metabolism. The results show that whole-body utilization of calories is the same with parenteral and enteral nutrition as evaluated over short time periods from the start of infusion. This is probably also true for amino acids.