Differences in energy expenditure in human donor milk versus formula milk in preterm newborns: A crossover study

Energy expenditure and body composition in infants with bronchopulmonary dysplasia at term age

In this cross-sectional study, conducted in a cohort of infants with a gestational age of < 32 weeks, we aimed to evaluate and compare resting energy expenditure (REE) and body composition between infants who developed bronchopulmonary dysplasia (BPD) and those who did not. REE and body composition were assessed at term equivalent age using indirect calorimetry and air displacement plethysmography. Anthropometric measurements (weight, head circumference, and length) were obtained and transformed into Z-scores per the Fenton (2013) growth curve, at birth and at term equivalent age. Forty-two infants were included in this study, of which 26.2% developed BPD. Infants with BPD had significantly higher energy expenditure at term equivalent age, with no difference in body composition between the two groups.

CONCLUSION

Despite expending more energy, infants with BPD maintained a similar body composition distribution to those without BPD, and this is likely due to the recommended nutritional approach.

WHAT IS KNOWN

• Greater resting energy expenditure impairs growth of preterm infants with bronchopulmonary dysplasia.

WHAT IS NEW

• Although preterm infants with bronchopulmonary dysplasia had a higher resting energy expenditure at the corrected term age, this did not affect their body composition and growth.

Energy Expenditure, Protein Oxidation and Body Composition in a Cohort of Very Low Birth Weight Infants

The nutritional management of preterm infants is a critical point of care, especially because of the increased risk of developing extrauterine growth restriction (EUGR), which is associated with worsened health outcomes. Energy requirements in preterm infants are simply estimated, so the measurement of resting energy expenditure (REE) should be a key point in the nutritional evaluation of preterm infants. Although predictive formulae are available, it is well known that they are imprecise. The aim of our study was the evaluation of REE and protein oxidation (Ox) in very low birth weight infants (VLBWI) and the association with the mode of feeding and with body composition at term corrected age. Methods: Indirect calorimetry and body composition were performed at term corrected age in stable very low birth weight infants. Urinary nitrogen was measured in spot urine samples to calculate Ox. Infants were categorized as prevalent human milk (HMF) or prevalent formula diet (PFF). Results: Fifty VLBWI (HMF: 23, PFF: 27) were evaluated at 36.48 ± 0.85 post-conceptional weeks. No significant differences were found in basic characteristics or nutritional intake in the groups at birth and at the assessment. No differences were found in the REE of HMF vs. PFF (59.69 ± 9.8 kcal/kg/day vs. 59.27 ± 13.15 kcal/kg/day, respectively). We found statistical differences in the protein-Ox of HMF vs. PFF (1.7 ± 0.92 g/kg/day vs. 2.8 ± 1.65 g/kg/day, respectively, p < 0.01), and HMF infants had a higher fat-free mass (kg) than PFF infants (2.05 ± 0.26 kg vs. 1.82 ± 0.35 kg, respectively, p < 0.01), measured with air displacement plethysmography. Conclusion: REE is similar in infants with a prevalent human milk diet and in infants fed with formula. The HMF infants showed a lower oxidation rate of proteins for energy purposes and a better quality of growth. A greater amount of protein in HMF is probably used for anabolism and fat-free mass deposition. Further studies are needed to confirm our hypothesis.