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Human alpha-lactalbumin and bovine beta-lactoglobulin absorption in premature infants
O O Kuitunen1, E Savilahti, A Sarnesto
1Children's Hospital, University of Helsinki, Finland.
Insights
Preterm infants absorb small amounts of alpha-lactalbumin (ALA) and beta-lactoglobulin (BLG), with absorption decreasing over time. Serum protein levels were not dependent on gestational age in these healthy infants.
Area of Science:
- Neonatology
- Pediatric Nutrition
- Immunology
Background:
- Infant feeding practices and protein absorption are critical for growth and development.
- Understanding the absorption of milk proteins like alpha-lactalbumin (ALA) and beta-lactoglobulin (BLG) in preterm infants is essential for optimizing nutritional strategies.
Purpose of the Study:
- To investigate the absorption of ALA and BLG in healthy preterm infants.
- To determine the changes in serum concentrations of these proteins over the first 8 months of life.
- To assess the relationship between protein absorption and infant gestational age.
Main Methods:
- A cohort of 23 healthy preterm infants (gestational age 32-36 wk) was studied.
- Serum concentrations of ALA and BLG were measured using time-resolved fluoroimmunoassay at various intervals up to 8 months.
- Absorption rates were calculated based on oral dose and serum levels.
Main Results:
- Measurable ALA was detected in all infants early after birth, with absorption decreasing significantly by 8 months.
- BLG was detected in a subset of infants after cow's milk introduction, with variable levels.
- Absorbed amounts of both ALA and BLG represented a small fraction (10^-5 to 10^-3) of the oral dose.
- Serum protein levels were independent of the infants' gestational age.
Conclusions:
- Preterm infants demonstrate absorption of ALA and BLG, but the levels are low and decline with age.
- The absorption of these proteins appears to be minimal shortly after weaning.
- Gestational age does not significantly influence the absorption of ALA and BLG in this cohort.
Abstract:
The absorption of alpha-lactalbumin (ALA) and bovine beta-lactoglobulin (BLG) was investigated in 23 healthy preterm infants with gestational ages of 32 to 36 wk. The concentrations of ALA and BLG in serum after a milk feeding were measured at intervals during the first 8 mo of life. We used a time-resolved fluoroimmunoassay to measure the proteins. Measurable amounts of ALA were found on d 7 after birth, and at 1, 2, 3, 5, and 8 mo in 23 of 23, 13 of 18, 13 of 18, six of 17, eight of 16, and five of 13, respectively, of the infants tested; median serum levels of ALA at the respective ages were 120 (range, 19-2598), 16 (range, 0-177), 5 (range, 0-40), 0 (range 0-3), 0.8 (range 0-38), and 0 (range, 0-22) micrograms/L serum/g ALA given/kg body wt, respectively. The rate of decline in ALA absorption was comparable among the infants. Tests for BLG were begun after the introduction of cow's milk. At 2, 3, 5, and 8 mo of age BLG was detected in two of 7, two of 9, eight of 10, and two of 12, respectively, of the infants tested, where median levels in positive cases were 13, 17, 15, and 3 micrograms/L serum/g BLG given/kg, respectively. The amounts of absorbed ALA and BLG were 10(-5) to 10(-3) of the oral dose. Serum levels of ALA or BLG did not depend on the gestational age of the infant. Few of the infants had any detectable absorption of either protein shortly after weaning.(ABSTRACT TRUNCATED AT 250 WORDS)