Elsevier

Early Human Development

Volume 83, Issue 12, December 2007, Pages 831-837
Early Human Development

Optimal protein and energy intakes in preterm infants

https://doi.org/10.1016/j.earlhumdev.2007.10.001Get rights and content

Abstract

There is compelling evidence that current nutritional practice fails to provide sufficient dietary protein for preterm infants, especially extremely and very low birth weight infants. Nutrient requirements can be estimated by a variety of techniques, but most suggest that these infants will require a protein intake of 3.5–4.0 g/kg/d. Even when these infants are able to tolerate full enteral feeds, most currently available artificial milk formula or breast milk fortifiers will not ensure these protein requirements are met except when fed at high volumes. Energy requirements on the other hand may be currently met, and evidence from controlled studies suggests that intakes higher than 110–135 kcal/kg/d might not be beneficial. The data from studies on neonatal adiposity outcomes, and from studies examining relationship between early growth and later cardiovascular outcome, also suggest that excess nutrient intake might be harmful. In the light of this data, optimal intakes and protein–energy ratios require re-appraisal.

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.

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