The fortification method relying on assumed human milk composition overestimates the actual energy and macronutrient intakes in very preterm infants

Abstract

BackgroundTo achieve recommended nutrient intakes in preterm infants, the target fortification method of human milk (HM) was proposed as an alternative to standard fortification method. We aimed to compare assumed energy and macronutrient intakes based on standard fortified HM with actual intakes relying on measured composition of human milk (HM), in a cohort of HM-fed very preterm infants.MethodsThis study is a secondary retrospective analysis, in which assumed energy and macronutrient contents of daily pools of own mother’s milk (OMM) from 33 mothers and donated HM (DHM) delivered to infants were compared with the measured values using a mid-infrared HM analyzer. A fortification method consisting of modular protein and/or fat supplements added to standard fortified HM was used to provide the minimum recommended daily intakes of energy 110 Kcal/kg and protein up to 4.0 g/kg. Assumed nutrient intakes were compared with actual nutrient intakes from full enteral feeding to 35 weeks plus 6 days postmenstrual age, using the Wilcoxon matched-pairs signed ranks test.ResultsThe composition of 1181 samples of daily pools of HM were measured. For 90.2% of study days, infants were exclusively fed OMM and in remaining days fed OMM plus DHM. Comparing with reported preterm OMM composition, measured protein concentration was significantly lower, and energy and other macronutrient concentrations were lower only from the second to third postnatal week. Using fortified HM, the actual median daily intakes of energy, protein, and fat were significantly lower (113.3 vs. 120.7 Kcal/kg, 4.45 vs. 4.73 g/kg, and 4.96 vs. 5.35 g/kg, respectively) and the actual protein-to-energy ratio (PER) significantly higher than what was assumed (4.2 vs. 4.0), without differences in carbohydrate intake.ConclusionsWhen fortifying the HM, we used conservative target intakes trying not to exceed the osmolarity recommended for infant feeds. Actual energy, protein and fat intakes in OMM were significantly lower than assumed. This resulted in inadequate intake using our fortification method, that did not compensate the suboptimal measured energy and macronutrient contents of OMM delivered. Further studies comparing assumed with the gold standard target fortification are needed to determine safe upper limits of assumed fortification.

Modifications of Own Mothers’ Milk Fortification Protocol Affect Early Plasma IGF-I and Ghrelin Levels in Preterm Infants. A Randomized Clinical Trial

“…Our findings are in line with studies by de Halleux and Rigo, who found that, compared to the individualized fortification group, the FF group received higher protein amounts, which were greater than the recommended levels in about 40% of the preterm infants [62]. In contrast, other authors reported a lower protein intake by the FF group, with only 64% of them attaining the lower recommended protein levels [63,64]. The conflicting results could be attributed to the use of different methodologies.…”

Customized Human Milk Fortification Based on Measured Human Milk Composition to Improve the Quality of Growth in Very Preterm Infants: A Mixed-Cohort Study Protocol

“…Recruitment for the contemporary cohort of infants fed target fortified HM was estimated to start in February 2020, with a scheduled recruitment period of 16 months. We planned to compare it with a historical cohort fed standard fortified HM in 2014–2015 [ 34 , 35 ], as stated in the ClinicalTrials.gov NCT04400396 registry. However, there was a shortage in modular protein supplement from February to July 2020, precluding the adoption of the new nutritional protocol using the target HM fortification.…”

“…However, there was a shortage in modular protein supplement from February to July 2020, precluding the adoption of the new nutritional protocol using the target HM fortification. In this context, the standard fortified HM arm will include infants from two cohorts: the historical study period (1 February 2014 to 28 February 2015) [ 33 , 34 ] plus the contemporary period from 1 February to 13 July 2020, during which the standard HM fortification was used.…”

“…The eligibility criteria are those followed by the historical cohort study [ 34 , 35 ], i.e., consecutive cases of newborns delivered <33 weeks of gestation, admitted to the NICU of Maternidade Dr. Alfredo da Costa (inborns and outborns), singletons or twins (=2), and exclusively HM-fed or predominantly (≥87.5% volume per day) HM-fed were eligible. Infants with a diagnosis of innate error of metabolism, those fed for two or more consecutive days with formula ≥12.5% of daily volume intake, and those transferred to other hospitals, deceased, or unavailable for body composition analysis after discharge will be excluded ( Figure 1 ).…”

“…In a cohort study of very preterm infants fed standard fortified HM, we previously evaluated the association between energy and macronutrient intakes and both weight gain velocity and body composition [ 34 , 35 ]. We concluded that the actual energy, protein, and fat intakes based on measured HM composition were significantly lower than the assumed intakes based on estimates of HM composition [ 34 ]. This nutritional strategy is associated with a suboptimal weight gain velocity and low adiposity [ 35 ].…”