Does amount of protein in formula matter for low-birthweight infants? A Cochrane systematic review.
BACKGROUND
High protein intake may be associated with negative consequences such as acidosis, uremia, and elevated levels of circulating amino acids (eg, phenylalanine levels). We performed a systematic review of randomized controlled trials to determine whether formula-fed low-birthweight infants could tolerate protein intakes>or=3.0 g/kg/d in their initial hospital stay, without adverse consequences.


METHODS
Randomized controlled trials contrasting levels of protein intakes as low (<3.0 g/kg/d), high (>or=3.0 g/kg/d but <4.0 g/kg/d), or very high protein intake (>or=4.0 g/kg/d) while other nutrients were held constant, were identified through a systematic search of the literature. Standard methods of the Cochrane Collaboration were used by 2 independent reviewers, with the third reviewer facilitating consensus decision making.


RESULTS
A meta-analysis of 5 randomized trials indicated improved weight gain (weighted mean difference [WMD] 2.36 g/kg/d; 95% confidence interval [CI] 1.31-3.40) and higher nitrogen accretion (WMD 143.7 mg/kg/d; 95% CI 128.7-158.8) with high (>or=3.0 g/kg/d but <4.0 g/kg/d) compared with low (<3.0 g/kg/d) protein intakes while other nutrients were kept constant. No data were available for IQ or Bayley scores at 18 months or later or for very high protein intakes (>or=4.0 g/kg/d). No significant differences were seen in rates of necrotizing enterocolitis, sepsis, or diarrhea.


CONCLUSIONS
Accelerated weight and nitrogen accretion were noted with higher protein intakes in "healthy" formula-fed low-birthweight infants. This benefit could not be weighed against the adverse consequences of elevated blood urea nitrogen levels and increased metabolic acidosis and neurodevelopmental abnormalities.
Premji
Shahirose
S
Faculty of Nursing and Paediatrics and Community Health Sciences, University of Calgary, Calgary, and the Alberta Children's Hospital, Canada. premjis@ucalgary.ca
Fenton
Tanis
T
Sauve
Reg
R
D004044:Dietary Proteins / Q000008:administration & dosage* / Q000009:adverse effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007223:Infant; D007227:Infant Nutritional Physiological Phenomena; D007230:Infant, Low Birth Weight / Q000254:growth & development*; D007231:Infant, Newborn; D007360:Intelligence / Q000187:drug effects / Q000502:physiology; D008297:Male; D009420:Nervous System / Q000187:drug effects; D009424:Nervous System Physiological Phenomena; D009584:Nitrogen / Q000378:metabolism; D016032:Randomized Controlled Trials as Topic; D015430:Weight Gain / Q000187:drug effects*
D004044:Dietary Proteins; D009584:Nitrogen