Relationship between human milk’s protein content and gastroesophageal reflux in preterm newborns

Objective: Human milk is the best nutritional choice also for preterm newborns. However, preterm human milk provides an insufficient amount of energy and nutrients are needed for rapid growth and normal development. Thus, preterm human milk is usually supplemented with commercially produced multicomponent fortifiers; however, human milk fortification (HMF) such that intake really meets requirements is difficult, because human milk protein and fat content is highly variable among mothers, gestational age, etc. There are no data about the effect of human milk content and fortification on gastroesophageal reflux (GER) in preterm newborns. Thus, we aimed to correlate human milk basal content and the main GER indexes in preterm newborns with symptoms of GER (frequent regurgitation and/or post-prandial desaturations). Methods: Seventeen preterm newborns with symptoms of GER underwent a 24-h monitoring of simultaneous oesophageal pH impedance. They were fed two human milk meals, two human milk and HMF3% meals and two human milk and HMF5% meals. Human milk protein and fat content was evaluated by near-infrared reflectance analysis and then correlated with the main GER indexes. Results: Human milk protein content ranged between 1.2 and 1.92 g/100 g of milk, and fat content between 3 and 6.3 g/100 g of milk. An inverse correlation between basal protein content and GER indexes was found (p<0.05). After fortification, this correlation tended to reverse. No correlation was found between fat content and GER. Conclusions: The evaluation of human milk content before fortification may improve the nutritional management of preterm infants with gastroesophageal reflux.