Protein and energy digestibility in preterm infants fed fortified human milk

The objective of the present study is to determine whether the apparent nutrient digestibility differs between very preterm infants fortified with bovine colostrum (BC) compared to those fortified with a conventional fortifier (CF), building on previous findings that BC was associated with looser stools and reduced need for laxatives in very preterm infants (VPI).

We conducted a 24-h digestibility balance study in 10 VPIs to assess the retention of protein, energy, and wet-weight following the intake of fortified human milk and collection of faecal excretions. Infants (n = 5) were matched by gestational age and birthweight.

In the 10 infants, the mean gestational age and birthweight were 28 ± 1 weeks and 899 ± 182 g, respectively. Infants fortified with BC had a higher faecal energy loss compared with infants fortified with CF (BC: 178 [range 111-205] vs. CF: 153 [96-235] kJ/kg, p < 0.05). No differences (p > 0.05) were found for wet-weight intake (421 [360-427] vs. 494 [328-500] kJ/kg), relative absorption of protein (60 [33-75] vs. 50 [33-75]%) or absolute protein absorption (249 [159-310) vs. 281 [210-347]).

Nutrient absorption was similar between groups although higher energy loss indicates reduced overall digestibility of BC versus CF, however, with a large variation within each group. Studies on more infants are required to confirm these results. A 24-h digestibility balance study can successfully be used to assess nutrient and energy retention in preterm infants.