Trans-vaccenic acid, the most abundant trans fatty acid found in human breast milk, helps boost immune system development and has long-lasting effects on immune system health in mice, according to a study by researchers from the University of Chicago published on June 18.
The study showed that nursing female mice fed a diet enriched with trans-vaccenic acid passed the nutrient to their pups, resulting in increased production of immune cells during early development. Genetic analyses revealed that exposure to this fatty acid during breastfeeding reprogrammed immune cells to improve responses to pathogens. Mice nursed on trans-vaccenic-acid-enriched milk responded faster to infections with viruses or common bacteria, even into adulthood.
Trans-vaccenic acid is a long-chain fatty acid found in meat and dairy products from grazing animals such as cows and sheep. The body cannot produce it independently; it must be obtained through diet. Previous research found that this nutrient improves the ability of certain T cells to infiltrate tumors and kill cancer cells in adult mice. In this new study, researchers aimed to understand how it might influence immune development early in life due to its abundance in human breast milk.
In experiments, only postnatal exposure through breastfeeding led to improved infection responses. "We saw that only postnatal exposure to TVA through breastfeeding is important to train the neonatal T cells, and this can have long-lasting imprinting effects," said Chen. "Even in adulthood, when we challenged the mice with influenza, the ones that were exposed to higher TVA levels during breastfeeding responded better when battling the infection."
The team also analyzed TVA levels in breast milk and blood samples from human nursing mothers and infants using resources at the UChicago Comprehensive Cancer Center Metabolomics Platform. They found higher TVA levels in breast milk were closely linked with higher infant blood levels; preterm infants showed similar shifts in immune response as seen in mice. Higher TVA was associated with reduced risk of bronchopulmonary dysplasia—a chronic inflammatory lung disease affecting premature infants.
Chen said working collaboratively across departments was crucial for success: "This was truly 'team science.' It definitely reflects the great collaborative environment here at UChicago," he said. With evidence supporting benefits of trans-vaccenic acid for early-life immunity, Chen hopes further research will explore supplementation possibilities during pregnancy or breastfeeding.
