Carbohydrate intake is the main determinant of growth in infants born <33 weeks' gestation when protein intake is adequate.
OBJECTIVE
We investigated the relative contribution of macronutrients to postnatal growth in preterm infants born <33 wk of gestation.


METHODS
An audit of daily parenteral and enteral intakes of protein, carbohydrate, fat, energy, and growth (daily weight, weekly length, and head circumference) from birth to discharge home in 138 infants at <33 wk of gestation admitted to an Australian tertiary hospital was done. A mixed-model analysis of variance with random effects (slope and intercept) for subject and controlling for time, sex, gestational age, and total energy was used to determine the relative contribution of macronutrients to growth.


RESULTS
A higher energy intake (kilocalories per day) had a positive influence on growth. With total energy held constant, the contribution of carbohydrate to total energy had a positive relation to weight, length, and head circumference gains; protein had no relation and fat was negatively associated. For every 1% increase in energy from carbohydrate, there was a 2.3-g/d increase in weight (95% confidence interval 1.6-3.0, P < 0.0001), a 0.013-cm/d increase in length (95% confidence interval 0.003-0.022, P = 0.007), and a 0.015-cm/d increase in head circumference (95% confidence interval 0.009-0.022, P < 0.0001).


CONCLUSIONS
A re-examination of the macronutrient balance in the diet of preterm infants is required in relation to optimizing growth.
Collins
Carmel T
CT
Child Health Research Institute, Women's and Children's Hospital, North Adelaide and Flinders Medical Centre, Bedford Park, South Australia, Australia.
Gibson
Robert A
RA
Miller
Jacqueline
J
McPhee
Andrew J
AJ
Willson
Kristyn
K
Smithers
Lisa G
LG
Makrides
Maria
M
D000704:Analysis of Variance; D001724:Birth Weight; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D004044:Dietary Proteins / Q000008:administration & dosage*; D002149:Energy Intake / Q000502:physiology; D005260:Female; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007227:Infant Nutritional Physiological Phenomena / Q000502:physiology*; D007231:Infant, Newborn; D007234:Infant, Premature / Q000254:growth & development*; D008297:Male; D009751:Nutritional Requirements; D015430:Weight Gain
D004040:Dietary Carbohydrates; D004044:Dietary Proteins