Key Findings
- Trans-vaccenic acid (TVA), a trans fatty acid found in human breast milk and dairy products from grazing animals, was shown to enhance immune system development in neonatal mice when passed through breastfeeding.
- Mice nursed by mothers fed a TVA-enriched diet exhibited increased production of CD4+ T cells—critical for adaptive immunity—and showed improved responses to influenza virus and Salmonella infections later in life.
- Genetic analyses indicated that TVA exposure during breastfeeding reprogrammed T cells to favor antimicrobial responses over allergic-type responses.
- The effect was specific to postnatal exposure through breastfeeding; pups exposed to TVA during pregnancy but nursed by mothers on a normal diet did not show the same immune benefits.
"It was surprising that one nutrient from the mother's diet delivered through breastfeeding has such a tremendous effect."
— Jing Chen, senior author, University of Chicago
Human Relevance
- Analysis of breast milk and blood samples from human mother-infant pairs showed that higher TVA levels in breast milk correlated with higher levels in infant blood.
- In preterm infants, higher TVA levels were associated with a reduced risk of bronchopulmonary dysplasia, a chronic lung disease.
Study Context
- The research was led by scientists at the University of Chicago and published in Science (2025).
- It builds on earlier work (2023) showing TVA improves CD8+ T cell activity against tumors in adult mice.
- The study was funded by the NIH, NCI, and other institutions.
Looking Ahead
The team plans to investigate other fatty acids and nutrients in breast milk for similar immune benefits, opening new possibilities for understanding how early nutrition shapes lifelong health.