Optimal protein and energy intakes in preterm infants
Section snippets
Assessment of nutritional status
Modern neonatal care has enabled the survival of many extremely low birthweight (ELBW < 1000 g) and very low birthweight (VLBW < 1500 g) infants. Two to three decades ago, neonatal intensive care was focused on respiratory and infectious morbidity. Advances in many areas have highlighted the critical importance of nutritional status in determining outcome. Unfortunately, there is no simple static ‘measure’ of nutritional status and no clear consensus on what outcome nutritional manipulation should
Optimal protein and energy intakes in the first few postnatal days
Catabolism of energy and protein stores commences as soon as the continuous placental supply of amino acids, glucose and essential fatty acids abruptly stops. Metabolic adaptation prepares newborn infants for this process, but both glycogen and fat stores are limited in ELBW infants. A 500 g infant at 24 weeks is composed of approximately 90% water with just 50 g of ‘dry’ tissue, of which only a few grams (< 1% total body weight) are fat. Heird has estimated that body stores for an infant
Optimal intakes in the subsequent postnatal weeks
Whilst the first few postnatal days are vitally important, most preterm infants receive much more nutrition via the enteral as compared to the parenteral route. There is overwhelming evidence to support the use of breast milk, but for many VLBW infants, and for all ELBW infants it will not meet nutrient needs alone. Optimal protein and energy intakes will then require the use of breast milk fortifiers and/or low birthweight formula.
Poor growth in the postnatal period has been documented in
Conclusions
Preterm infants are nutritionally vulnerable and careful management of their energy and protein requirements is essential if their outcome is to be optimised. However, any potential short term growth benefits from increasing intakes of protein and energy need to be considered alongside the potential for adverse long term metabolic adaptation [3]. Some have suggested a more cautious approach to promoting ‘catch-up’ growth. However, these long term epidemiological studies have demonstrated that
Acknowledgements/Conflict of Interest
Dr Embleton has received grants from Royal Numico, SHS International and Nutricia to support research examining nutritional requirements in preterm infants, but has received no personal payment, and has no other financial relationship with these organisations. No commercial organisation was involved in the preparation of this manuscript.
References (56)
Nutrition and the developing brain: nutrient priorities and measurement
Am J Clin Nutr
(2007)- et al.
Energy costs of fat and protein deposition in the human infant
Am J Clin Nutr
(1988) - et al.
Clinical effects of two different levels of protein intake on low-birth-weight infants
J Pediatr
(1969) - et al.
Evidence supporting early nutritional support with parenteral amino acid infusion
Sem Perinatol
(2007) - et al.
Amino acid administration to premature infants directly after birth
J Pediatr
(2005) - et al.
Parenteral amino acid and energy administration to premature infants in early life
Sem Fetal Neo Med
(2007) - et al.
Immediate commencement of amino acid supplementation in preterm infants: effect on serum amino acid concentrations and protein kinetics on the first day of life
J Pediatr
(1995) Regulation of proteolysis and optimal protein accretion in extremely premature newborns
Am J Clin Nutr
(2007)- et al.
Exogenous insulin reduces proteolysis and protein synthesis in extremely low birth weight infants
J Pediatr
(1998) - et al.
Glutamine supplement with parenteral nutrition decreases whole body proteolysis in low birth weight infants
J Pediatr
(2005)
Short-term growth and substrate use in very-low-birth-weight infants fed formulas with different energy contents
Am J Clin Nutr
Effects of varying protein and energy intakes on growth and metabolic response in low birth weight infants
J Pediatr
Growth, nutrient retention, and metabolic response in low birth weight infants fed varying intakes of protein and energy
J Pediatr
Enteral intake for very low birth weight infants: what should the composition be?
Sem Perinatol
Is slower early growth beneficial for long-term cardiovascular health?
Circulation
Promotion of faster weight gain in infants born small for gestational age: is there an adverse effect on later blood pressure?
Circulation
Altered adiposity after extremely preterm birth
Pediatr Res
Non-protein nitrogen and true protein in infant formulas
Acta Paediatr
Protein metabolism in preterm infants with particular reference to intrauterine growth restriction
Arch Dis Child
Nutrient requirements of premature infants. Nestle Nutrition Workshop Series
Paediatric Programme
Body composition of the reference fetus
Growth
Energy expended by low birth weight infants in the deposition of protein and fat
Pediatr Res
Differences between metabolism and feeding of preterm and term infants
Partition of energy metabolism and energy cost of growth in the very low-birth-weight infant
Pediatrics
Nutrient requirements for preterm infant formulas
J Nutr
Protein and energy requirements of low birth weight infants
Acta Paed Scand - Supp
Aggressive early total parental nutrition in low-birth-weight infants
J Perinatol
Effect of low versus high intravenous amino acid intake on very low birth weight infants in the early neonatal period
Pediatr Res
Cited by (75)
Low birth weight and preterm infants: Nutritional management
2023, Encyclopedia of Human Nutrition: Volume 1-4, Fourth EditionMilk analysis using milk analyzers in a standardized setting (MAMAS) study: A multicentre quality initiative
2020, Clinical NutritionCitation Excerpt :Measurement errors of 1 g of protein per dL will lead to differences in protein intake by 1.6 g/kg/day, which would result in differences in growth rates of 8–10 g/kg/day. Such differences in growth rates are clinically meaningful [22]. Moreover, there is not only a risk of not providing sufficient nutrient intake, but there is also a risk that these measurements errors could lead to severe overfortification (e.g. 5.5 instead of 4.0 g of protein/kg/day), leading to overgrowth and unfavourable fat mass composition.
Protein intakes to optimize outcomes for preterm infants
2019, Seminars in PerinatologyCitation Excerpt :If there is insufficient energy available, the amino acid concentrations will rise and the amino acids will be oxidized for energy generation, leading to the formation of ammonia and subsequent urea. In order to prevent unwanted oxidation, it is therefore recommended to supplement around 30–40 kcal of total energy per gram of administered proteins, although slightly lower total energy intakes around 25–30 kcal/g appear to be sufficient when amino acids are administered parenterally.6 The fetus receives a continuous supply of amino acids via the placenta, estimated at about 3.5–4.0 g/kg per day, of which up to half is oxidized.7