From the Guidelines
Premature infants should receive a daily protein intake of 2.5-3.5 g/kg/d from postnatal day 2 onwards, with an initial intake of at least 1.5 g/kg/d on the first postnatal day. This recommendation is based on the strongest and most recent evidence from the 2018 espghan/espen/espr/cspen guidelines on pediatric parenteral nutrition: amino acids 1. The guidelines suggest that in preterm infants, the amino acid supply should start on the first postnatal day with at least 1.5 g/kg/d to achieve an anabolic state, and from postnatal day 2 onwards, the parenteral amino acid intake should be between 2.5 g/kg/d to 3.5 g/kg/d, accompanied by non-protein intakes >65 kcal/kg/d and adequate micronutrient intakes.
Key considerations for protein intake in premature infants include:
- Starting protein intake within the first 24 hours of life to support rapid growth and development
- Gradually increasing protein intake to the target range over the first few days of life
- Ensuring sufficient non-protein calories to support protein utilization for growth rather than energy
- Regular monitoring of growth parameters, blood urea nitrogen, and serum albumin levels to ensure appropriate protein utilization and tolerance
- Avoiding protein intakes above 3.5 g/kg/d, which should only be administered as part of clinical trials, as recommended by the guidelines 1.
The recommended protein intake range of 2.5-3.5 g/kg/d is necessary to support the unique nutritional needs of premature infants, including their rapid growth rate, limited protein stores, and immature metabolic pathways. By following this recommendation, healthcare providers can help promote appropriate growth, neurodevelopment, and prevent postnatal growth restriction in premature infants.
From the Research
Recommended Daily Protein Intake for Premature Infants
- The recommended daily protein intake for premature infants varies, but most studies suggest a range of 2-4 g/kg/day 2, 3, 4.
- A study published in 2013 recommends starting parenteral nutrition with 2-3 g/kg/day of amino acids and increasing intake to 3.5 g/kg/day during the first week of life 2.
- Another study published in 2020 found that high doses of amino acids (up to 4.0-4.5 g/kg/day) in early parenteral nutrition facilitated early growth and development in preterm infants 5.
- A review of protein requirements for preterm infants published in 2010 suggests that protein requirements at 24-30 weeks' gestation are as high as 4 g/kg/day, decreasing to 2-3 g/kg/day by term 3.
- A study published in 2007 estimates that preterm infants require a protein intake of 3.5-4.0 g/kg/d, which is often not met by current nutritional practices 4.
- A systematic review published in 2014 found that higher protein intake results in increased growth in preterm infants, with intakes as high as 4.5 g/kg/day shown to be safe in infants weighing >1000 g 6.