RESUMO
BACKGROUND & AIMS: In preterm infants, natural variation of breast milk composition makes it difficult to achieve recommended macronutrient intakes with standard fortification. Evidence suggests that nutritional deficiency induces poor postnatal growth. This study investigates impacts of target fortification on preterm growth and metabolism by adjusting breast milk macronutrients. METHODS: This study was conducted as a single-centre, double-blind, randomized controlled trial for infants <30 gestational weeks. The control group received standard fortification and the intervention group received standard plus target fortification adding modular protein, lipids, and carbohydrates. Breast milk content was measured 3x/week using a validated near-infrared bedside spectrometer (NIRS). Modulars were added to achieve recommended values. To assess total nutrient intake, all 2810 native breast milk samples were analyzed - protein and fat using bedside-NIRS, lactose using tandem mass spectrometry (UPLC-MS/MS). Body composition was measured using air displacement plethysmography. Primary outcome was weight gain during the first 21 days of intervention. RESULTS: Baseline characteristics, morbidities, and total fluid intake were not different between groups (intervention n = 52, control n = 51). The intervention group infants had higher macronutrient intakes, weight gain (21.2 ± 2.5 vs 19.3 ± 2.4 g/kg/d, mean difference: 1.9 g/kg/d, 95% CI: 0.9 - 2.9), and body weight. Infants in the intervention group from mothers with below-average breast milk protein content showed greatest impact on weight at 36 weeks (2580 ± 280 g vs 2210 ± 300 g), length, head circumference, fat, and fat-free mass. Also, feeding intolerance was less frequent, blood urea was higher, and triglycerides were lower. CONCLUSIONS: This study provides evidence that target fortification of breast milk with low macronutrient content enhances the quality of nutrition and growth and is feasible in clinical routine.