Health · Medical Research · 1 hr ago
Breast milk sugar linked to lower jaundice severity in mice
Researchers at the University of California San Diego studied how a breast milk sugar affects jaundice in young mice.
The sugar, called 3'-sialyllactose, was linked to intestinal development and the processing of bilirubin, a substance that can build up and cause yellowing of the skin and eyes.
Mice fed milk without the sugar had more severe jaundice and poorer growth than other pups.
They also had lower levels of an enzyme that helps the body clear bilirubin.
Infant jaundice affects up to 60% of full-term babies and 80% of premature babies, and is usually mild, but high or lasting bilirubin levels can harm the brain.
The findings suggest differences in breast milk sugar levels may help explain why jaundice is more severe in some infants, but the study was in mice.
The researchers say the work could point to nutritional approaches to support intestinal development, though further research is needed to understand what this means for human babies.
A study in mice found that the breast milk sugar 3'-sialyllactose (3'SL) was linked to less severe jaundice.
Mouse pups fed milk without 3'SL had lower survival, poorer growth, shorter intestines and more severe jaundice.
The pups also had lower intestinal levels of UGT1A1, an enzyme that helps clear bilirubin.
Researchers said the findings suggest breast milk sugar composition may help explain differences in jaundice severity among infants.
The study was led by researchers at the University of California San Diego School of Medicine and published in Cellular and Molecular Gastroenterology and Hepatology.
- Who
- Researchers at the University of California San Diego School of Medicine, led by Robert Tukey.
- What
- A mouse study found that 3'SL in milk supports intestinal maturation and bilirubin processing, and that its absence was linked to more severe jaundice.
- When
- The study was reported on November 4, 2026.
- Where
- The research was conducted in mice at the University of California San Diego.
- Why
- Researchers investigated how sugars in breast milk may affect gut health and bilirubin metabolism.
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- Milk sugar
- 3'-sialyllactose (3'SL)
- Bilirubin-clearing enzyme
- UGT1A1
- Study species
- Mice
- Lead researcher
- Robert Tukey, University of California San Diego School of Medicine
- Journal
- Cellular and Molecular Gastroenterology and Hepatology
What people are saying
Our results suggest that early milk exposure could have lasting, systemic impacts on gut resilience
Our research also suggests that natural differences in milk sugar composition could help explain why some infants develop more severe jaundice than others.
This raises the possibility of nutritional strategies that could help support intestinal maturation and prevent jaundice.