Postnatal dietary undernutrition and concurrent extrauterine
growth restriction are associated with adverse
consequences, the most notable of which is long-term
neurodevelopmental deficits.22–25 Improved cognitive
performance at 18 months and at 7–8 years has been
demonstrated in children who were born preterm and
received a nutrient-enriched preterm formula compared
to those receiving standard infant formula.26 However,
postnatal over-nutrition, and rapid catch-up growth, also
appears to place the preterm infant at risk.27,28 High nonprotein
energy feeding of low-birth-weight infants results
in an increase in weight due to body fat rather than a gain
in lean body mass.29 High-protein diets, while known to
be associated with increased growth and neurodevelopment,9
may also pose a potential problem for increased
adipose formation and later obesity.
The hypothesis that increased protein received by
formula-fed infants may contribute to obesity is being
tested by the European Childhood obesity and protein
in infant nutrition (CHOPIN) study (http://clinicaltrials.
gov/ct2/show/NCT00338689). In this randomized
double-blind intervention trial, formula-fed infants
receive either a higher or a lower protein formula during
the first year of life. Follow-up at 2 years of age has demonstrated
that lower protein formula results in a growth
trajectory that mimics that of a breastfed infant and thus
may be associated with lower rates of obesity.30 Although
the focus of this review is prematurity, it is important to
note in the context of postnatal dietary compositions that
breast milk appears to have a protective effect against the
development of metabolic disease in term infants. Evidence
suggests that breastfed infants have lower blood
pressure, lower total cholesterol, and a lower prevalence
of overweight and obesity.31–33 The apparent dichotomy
surrounding postnatal nutrient balance presents a challenging
problem in the clinical arena and a robust evaluation
of the long-term effects of postnatal nutrition is
necessary to formulate effective feeding strategies for the
preterm infant.
RATE OF POSTNATAL GROW