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beta-Glucuronidase and hyperbilirubinaemia in breast-fed and formula-fed babies
Insights
Breast milk contains beta-glucuronidase, an enzyme linked to higher infant jaundice (neonatal hyperbilirubinaemia). This enzyme in breast milk and infant feces correlates with elevated bilirubin levels in breast-fed infants.
Area of Science:
- Neonatology
- Pediatric Gastroenterology
- Biochemistry
Background:
- Neonatal hyperbilirubinaemia, or infant jaundice, is common.
- Breast milk is often associated with higher bilirubin levels compared to formula.
- The specific mechanisms driving breast milk-associated jaundice require further elucidation.
Purpose of the Study:
- To investigate the role of beta-glucuronidase in neonatal hyperbilirubinaemia.
- To compare beta-glucuronidase activity in breast milk, formula, and infant feces.
- To explore the correlation between beta-glucuronidase levels and serum bilirubin in infants.
Main Methods:
- Serum and milk samples were collected from breast-fed and formula-fed infants and their mothers at 3 and 21 days of neonatal age.
- Infant fecal samples were collected on day 21.
- Beta-glucuronidase activity was measured in milk and fecal samples; serum total bilirubin was quantified.
Main Results:
- Serum total bilirubin was significantly higher in breast-fed infants compared to formula-fed infants at both time points.
- Human milk exhibited considerable beta-glucuronidase activity, while formula milk had negligible levels.
- Higher fecal beta-glucuronidase activity was observed in breast-fed infants on day 21, correlating with breast milk enzyme levels and serum bilirubin.
Conclusions:
- Breast milk beta-glucuronidase appears to be a significant contributing factor to neonatal hyperbilirubinaemia in breast-fed infants.
- A temporary switch from breast milk to formula led to decreased fecal beta-glucuronidase and reduced serum bilirubin levels.
- These findings highlight the enzymatic activity in breast milk as a key element in understanding infant jaundice.
Abstract:
Breast milk or formula milk and serum samples from 34 breast-fed babies, 15 formula-fed babies, and their mothers were examined at 3 and 21 days of neonatal age. Infant faecal samples were obtained on day 21 only. At both ages serum total bilirubin concentrations were significantly higher in breast-fed than in formula-fed infants. Beta-glucuronidase activity in formula milk was negligible while that in human milk was considerable. Day 21 faecal beta-glucuronidase was higher in the breast-fed babies. In the breast-fed babies, serum bilirubin levels were related to concentrations of beta-glucuronidase in breast milk on both days 3 and 21 and to levels of faecal beta-glucuronidase on day 21. In 4 additional babies whose feeds were temporarily changed from breast milk to formula milk because of hyperbilirubinaemia there was a striking decrease in faecal beta-glucuronidase activity coincident with a fall in serum bilirubin. Breast milk beta-glucuronidase seems to be an important factor in the neonatal hyperbilirubinaemia of breast-fed babies.