Energy requirements, protein-energy metabolism and balance, and carbohydrates in preterm infants

William W. Hay, Laura D. Brown, Scott C. Denne

Research output: Chapter in Book/Report/Conference proceedingChapter

16 Scopus citations


Energy is necessary for all vital functions of the body at molecular, cellular, organ, and systemic levels. Preterm infants have minimum energy requirements for basal metabolism and growth, but also have requirements for unique physiology and metabolism that influence energy expenditure. These include body size, postnatal age, physical activity, dietary intake, environmental temperatures, energy losses in the stool and urine, and clinical conditions and diseases, as well as changes in body composition. Both energy and protein are necessary to produce normal rates of growth. Carbohydrates (primarily glucose) are principle sources of energy for the brain and heart until lipid oxidation develops over several days to weeks after birth. A higher protein/energy ratio is necessary in most preterm infants to approximate normal intrauterine growth rates. Lean tissue is predominantly produced during early gestation, which continues through to term. During later gestation, fat accretion in adipose tissue adds increasingly large caloric requirements to the lean tissue growth. Once protein intake is sufficient to promote net lean body accretion, additional energy primarily produces more body fat, which increases almost linearly at energy intakes >80-90 kcal/kg/day in normal, healthy preterm infants. Rapid gains in adiposity have the potential to produce later life obesity, an increasingly recognized risk of excessive energy intake. In addition to fundamental requirements for glucose, protein, and fat, a variety of non-glucose carbohydrates found in human milk may have important roles in promoting growth and development, as well as production of a gut microbiome that could protect against necrotizing enterocolitis.

Original languageEnglish (US)
Title of host publicationNutritional Care of Preterm Infants
Subtitle of host publicationScientific Basis and Practical Guidelines
PublisherS. Karger AG
Number of pages18
ISBN (Print)9783318026405
StatePublished - Jan 1 2014

Publication series

NameWorld Review of Nutrition and Dietetics
ISSN (Print)0084-2230
ISSN (Electronic)1662-3975

ASJC Scopus subject areas

  • Food Science
  • Nutrition and Dietetics

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    Hay, W. W., Brown, L. D., & Denne, S. C. (2014). Energy requirements, protein-energy metabolism and balance, and carbohydrates in preterm infants. In Nutritional Care of Preterm Infants: Scientific Basis and Practical Guidelines (pp. 64-81). (World Review of Nutrition and Dietetics; Vol. 110). S. Karger AG.