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Published on: August 24, 2011
Plasma amino acids in preterm infants after a feed of human milk or formula
Insights
Plasma amino acid levels in preterm infants change rapidly after feeding. Measuring these levels before feeds is crucial for assessing infant tolerance to different milk protein loads.
Area of Science:
- Neonatology
- Biochemistry
- Pediatric Nutrition
Background:
- Preterm infants require careful nutritional management.
- Human milk and formula have different protein compositions.
- Understanding amino acid metabolism is key for infant health.
Purpose of the Study:
- To analyze plasma amino acid changes in preterm infants after consuming human milk or formula.
- To compare responses to varying protein quantities and qualities.
- To establish optimal timing for blood sampling in preterm infants.
Main Methods:
- Measured prefeeding and postprandial plasma amino acid concentrations.
- Included 31 healthy preterm infants (33-37 weeks gestational age).
- Infants received human milk or adapted/nonadapted milk formula.
Main Results:
- Essential and nonessential amino acids (e.g., arginine, ornithine) increased postprandially.
- Glycine levels decreased, while alanine increased slowly.
- Plasma amino acid fluctuations reflected the protein content of the feeds.
Conclusions:
- Plasma amino acid concentrations in preterm infants are dynamic and influenced by feed protein.
- Blood samples for studies should be collected immediately before feeding.
- Postprandial amino acid analysis can assess infant tolerance to protein loads.
Abstract:
Prefeeding and sequential postprandial plasma amino acid concentrations were measured in 31 healthy preterm infants with gestational ages between 33 and 37 weeks at the ages of 4 to 12 days, to characterize changes after quantitatively and qualitatively different protein loads. All infants had previously been fed with human milk. The infants received a normal feed of pooled human milk (true protein 0.8 gm/dl) or of adapted or nonadapted milk formula (protein 1.5 gm/dl) from a bottle. The concentrations of all essential and several nonessential amino acids, including arginine and ornithine, rose sharply in plasma. Glycine decreased, and alanine increased slowly. Postprandial alterations in plasma total amino acids seemed to reflect the protein content of the different milks. In preterm infants, fed at three- to four-hour intervals, plasma amino acid concentrations fluctuate continuously. Thus in long-term studies and in screening, samples should be taken immediately before feeds. Postprandial plasma amino acid measurements may prove to be a useful means for testing the infant's ability to handle the protein or individual amino acid loads in various feeds.
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