Postprandial thermogenesis in human milk-fed very low birth weight infants.

Postprandial thermogenesis in 10 human milk-fed very low birth weight infants was studied by indirect calorimetry at thermoneutrality. Throughout a period of 5-6 weeks each infant was tested once weekly which enabled the authors to explore the relationship between postprandial metabolism and postnatal age as well as growth rate. A feed of human milk caused, on the average, a 15% increase in metabolism. The effect reached its peak value between 50 and 80 min; thereafter it began to fall and approached the preingestion level at 120 min. The response obtained in the 4th, 5th and 6th postnatal week was more pronounced than in the first 3 weeks. Analysis based on growth rate showed that infants exhibiting a rapid weight gain responded by a larger increase in postprandial metabolism than the non- or slow-growing infants.