The identified trials provide only low quality evidence about the effects of feeding preterm infants  with protein hydrolysate versus st and ard formula .
The existing data did not support conclusions that feeding with protein hydrolysate affects the risk of feed intolerance or necrotising enterocolitis .
BACKGROUND When human milk is not available for feeding preterm infants , protein hydrolysate rather than st and ard cow 's milk formulas ( with intact proteins ) are often used because they are perceived as being tolerated better and less likely to lead to complications .
However , protein hydrolysate formulas are more expensive than st and ard formulas , and concern exists that their use in practice is not supported by high- quality evidence .
OBJECTIVES To assess the effect of feeding preterm infants with hydrolysed formula ( versus st and ard cow 's milk formulas )  on the risk of feed intolerance , necrotising enterocolitis , and  other morbidity and mortality in preterm infants .
Protein hydrolysate formula maintains homeostasis of plasma amino acids in preterm infants.
BACKGROUND Plasma amino acid concentrations were measured in preterm infants who were fed either a new hydrolyzed cow 's milk protein formula or a st and ard preterm infant formula .  It was hypothesized that feeding with the hydrolysate results in prepr and ial amino acid concentrations that are significantly different from the concentrations found when feeding with the st and ard formula . METHODS Fifteen preterm infants , median gestational age , 29 weeks ( range , 24 - 32 weeks ) ; birth weight , 1241 g ( range , 660 - 1900 g ) ; and postnatal age , 18 days ( range , 7 - 54 days ) receiving full enteral feedings ( > 150 ml/kg x day ) , were enrolled . The intervention was r and omized allocation to the formula with hydrolyzed or natural cow 's milk protein ( the whey/casein ratio was 60:40 in both formulas ) . In a crossover design , each formula was fed for 5 days , and plasma amino acids were analyzed on day 4 or 5 of each 5-day period . RESULTS In spite of the 12 % higher amino acid intake with hydrolysate formula , the median individual plasma amino acid concentrations were virtually identical with both formulas , and they were within the 10th and the 90th percentile of the reference of levels in the umbilical cord artery after elective cesarean delivery or of breast-fed newborn infants . The median concentrations of lysine and aspartic acid were higher with hydrolyzed formula feeding ( p<0.05 ; two-tailed Mann-Whitney test ) . With both formulas , single amino acid concentrations were out of the reference values . CONCLUSION Virtually identical plasma amino acid concentration patterns were measured with the new hydrolyzed preterm infant formula and the st and ard preterm infant formula , but longitudinal studies are required before the studied protein hydrolysate can be recommended for preterm feeding in general
The identified trials provide only low quality evidence about the effects of feeding preterm infants  with protein hydrolysate versus st and ard formula .
The existing data did not support conclusions that feeding with protein hydrolysate affects the risk of feed intolerance or necrotising enterocolitis .
BACKGROUND When human milk is not available for feeding preterm infants , protein hydrolysate rather than st and ard cow 's milk formulas ( with intact proteins ) are often used because they are perceived as being tolerated better and less likely to lead to complications .
However , protein hydrolysate formulas are more expensive than st and ard formulas , and concern exists that their use in practice is not supported by high- quality evidence .
OBJECTIVES To assess the effect of feeding preterm infants with hydrolysed formula ( versus st and ard cow 's milk formulas )  on the risk of feed intolerance , necrotising enterocolitis , and  other morbidity and mortality in preterm infants .