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

Objective: The aim of this study was to compare the ratio between energy expenditure and caloric density in human donor milk versus formula milk in preterm newborn infants.

Methods: This was a crossover, randomized clinical trial with 29 preterm newborn infants receiving full diet. The infants were randomly assigned to receive either human milk or formula milk alternating, after a 24-h period. Energy expenditure was evaluated by indirect calorimetry. Total calorie and macronutrient values in the human milk were calculated individually with infrared technique; energy expenditure/caloric density ratio was calculated.

Results: Human donor milk energy expenditure/caloric density ratio was significantly greater than in formula milk at all time points. The total mean was 1.04 ± 0.27 for the human milk and 0.81 ± 0.11 for the formula. However, when we analyzed a subgroup of newborns that received human donor milk with >60 kcal/100 mL, there was no statistical difference (P = 0.36). The mean calorie values were 58.9 kcal/100 mL (human donor milk) and 81.4 kcal/100 mL (formula milk).

Conclusion: Formula milk produced a better metabolic response than human donor milk. Human donor milk with higher caloric content showed no difference from formula, so the use of human donor milk with more caloric density should be reinforced.