Premature Infants have Lower Gastric Digestion Capacity for Human Milk Proteins than Term Infants

Abstract

Preterm infants have lower gastric protein digestion capacity than term infants, which could impair nutrient acquisition. Human milk proteases contribute minimally to overall gastric digestion. The limited activity of milk proteases suggests that these enzymes cannot compensate for the premature infant's overall lower gastric protein digestion.

The preterm infant stomach actively degrades milk proteins with increasing breakdown across digestion time

“…The loss of major milk proteins observed in the previous study is illustrated as the increase in primary amine concentration in this study. Our results also matched with our previous study's observations that the proteolysis increased from human milk to the gastric contents at two hours postprandial in preterm infants. Moreover, the mM primary amines observed in preterm infant gastric samples in this study from one to three hours postprandial are similar to those observed previously at two hours postprandial in preterm infants and lower than those reported for term infants.…”

“… (by dividing our values by infant body weight in kilograms and converting to 0.1 μ mol/min tyrosine per unit) yielded similar values: 68 ± 14, 44 ± 5, 62 ± 12 U/mL/kg of body weight at one, two and three hours post‐ingestion, respectively. Our findings that general protease did not change at one or three hours matched with our previous study observations that overall protease activity did not increase from human milk to the preterm infant stomach at two hours postprandial. This recent research also found that the general protease activity was lower in human milk‐fed preterm infants than term infants at two hours postprandial.…”

“…Our findings that general protease did not change at one or three hours matched with our previous study observations that overall protease activity did not increase from human milk to the preterm infant stomach at two hours postprandial. This recent research also found that the general protease activity was lower in human milk‐fed preterm infants than term infants at two hours postprandial.…”

“…Our previous study found that cathepsin D and plasmin from human milk were still active in the preterm stomach at two hours postprandial. Our recent research also demonstrated that pepsin/cathepsin D activities and proteolysis increased from human milk to the preterm infant stomach at two hours postprandial. However, the extent to which protease digestion changes across time postprandial in the preterm infant stomach remained unknown.…”

“…However, pepsin concentration did not change with BW b or GA. Preterm infants have higher prefeeding gastric pH than term infants , but no difference in postprandial gastric pH was found between preterm and term infants. Our recent study demonstrated that gastric pH at two hours postprandial in preterm and term infants fed with human milk did not differ, most likely due to the strong buffering effect of human milk and the higher amount of meal volume fed by term infants compared with preterm infants. As gastric hydrochloric acid can protect against pathogens , the higher pH in the prefed state could make preterm infants more susceptible to infection.…”