Effect of the quality of infused energy on substrate utilization in the newborn receiving total parenteral nutrition.
Newborn infants (n = 26), subdivided into three groups in which only the nonprotein energy was manipulated, were studied during continuously administered total parenteral nutrition. Nonprotein energy intake was provided as a glucose/fat mixture, and fat energy represented 18% (group A), 29% (group B), and 40% (group C). Energy expenditure and substrate utilization were measured by indirect calorimetry during a 6-h period. Other analyses included 24-h urinary nitrogen excretion, glycemia, and lipid profile. The results showed that glucose oxidation increased with increasing total glucose intake (p < 0.05). Net fat oxidation was observed in all groups and increased with increasing percentage of energy infused as fat. The maximal oxidative glucose disposal rate observed was in group A (11.2 g/kg/d). Maximal fat oxidation observed was in group C (2 g/kg/d), in which energy delivered by fat represented 40%. This group was more energy efficient than the others. Oxygen consumption was not affected by modification of the source of energy, but carbon dioxide production was higher in group A (p < 0.05), as was the nonprotein respiratory quotient (p < 0.05). Despite differences in carbon dioxide production, arterial capillary PCO2 was not affected and, together with the higher (p < 0.05) minute ventilation, suggests that adequate pulmonary compensation occurred during the low-fat regimen. Arterial capillary PO2 was lower during the high-fat regimen (p < 0.05). Protein oxidation was greater in group A (1.14 +/- 0.32 g/kg/d) than in group B (0.70 +/- 0.21 g/kg/d) or group C (0.78 +/- 0.28 g/kg/d).(ABSTRACT TRUNCATED AT 250 WORDS)
Salas-Salvadó
J
J
Research Unit on Human Nutrition and Growth, Pediatrics, University of Barcelona, Reus, Spain.
Molina
J
J
Figueras
J
J
Massó
J
J
Martí-Henneberg
C
C
Jimenez
R
R
D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D007227:Infant Nutritional Physiological Phenomena; D007231:Infant, Newborn / Q000378:metabolism* / Q000502:physiology; D008297:Male; D010289:Parenteral Nutrition, Total; D011506:Proteins / Q000378:metabolism; D011659:Pulmonary Gas Exchange
D004040:Dietary Carbohydrates; D004041:Dietary Fats; D011506:Proteins