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Macromolecular absorption in preterm and term infants
I Axelsson1, I Jakobsson, T Lindberg
1Department of Paediatrics and Experimental Research, University of Lund, Malmö General Hospital, Sweden.
Insights
Human alpha-lactalbumin (alpha-LA) absorption is higher in premature infants. Alpha-LA serum concentration decreases with infant maturity and postnatal age.
Area of Science:
- Biochemistry
- Neonatology
- Pediatric Nutrition
Background:
- Human alpha-lactalbumin (alpha-LA) is a key whey protein in human milk.
- Alpha-LA serves as a valuable marker for assessing macromolecular absorption in infants.
- Understanding absorption dynamics is crucial for optimizing infant nutrition and growth.
Purpose of the Study:
- To investigate the serum concentration of human alpha-lactalbumin (alpha-LA) in very low birthweight (VLBW) infants and term infants after human milk feeds.
- To determine how infant maturity and postnatal age influence alpha-LA absorption.
- To establish reference ranges for alpha-LA serum concentrations in different infant populations.
Main Methods:
- Serum samples were collected from 32 VLBW infants (gestational age 26-32 weeks) and 56 term infants (3-140 days old) after human milk feeding.
- Alpha-LA concentrations were measured using established laboratory techniques.
- Data were analyzed to compare serum alpha-LA levels based on gestational age, postconceptional age, and postnatal age.
Main Results:
- VLBW infants at 31 weeks gestation exhibited significantly higher serum alpha-LA concentrations (mean 3,000 µg/l) compared to term infants in the first 30 days of life (mean 257 µg/l).
- Serum alpha-LA levels demonstrated a decline with increasing maturity in VLBW infants, reaching levels comparable to term infants by 37 weeks postconceptional age.
- In term infants, alpha-LA absorption decreased progressively with advancing postnatal age.
Conclusions:
- Infant maturity is a significant factor influencing human alpha-lactalbumin absorption, with premature infants showing greater absorption.
- The decreasing serum alpha-LA concentrations with age highlight the maturation of the infant's gastrointestinal barrier function.
- These findings have implications for understanding nutrient absorption and gastrointestinal development in neonates.
Abstract:
Human alpha-lactalbumin (alpha-LA) has been used as a marker for measuring macromolecular absorption. The serum concentration of human alpha-LA after a human milk feed has been studied in 32 healthy very low birthweight infants (VLBW), fed human milk (gestational age 26-32 weeks) and in 56 term, breast-fed infants, age 3-140 days. At 31 weeks of gestation the serum concentration of human alpha-LA was more than 10 times higher (mean value 3,000 and median value 2,101 micrograms/l serum/l human milk/kg body weight, n = 11) than in the term infants aged 3-30 days (mean value 257 and median value 152, n = 29). The serum concentration of alpha-LA decreased with increasing maturity in the VLBW-infants. At a postconceptional age of 37 weeks the values were similar (mean value 200 and median value 99, n = 8) to those found for term infants during the first month. In the term infants a decreasing absorption of alpha-LA was found with increasing postnatal age.