Breast milk nutrient boosts long-term immune system development

Trans-vaccenic acid (TVA), a fatty acid found in grazing animal products and human breast milk, improves neonatal immune development by reprogramming T cells to better fight pathogens, according to a University of Chicago study published in Science. Researchers found this postnatal exposure creates long-term immune imprinting that lasts into adulthood.

Why does trans-vaccenic acid (TVA) matter for infant health?

TVA acts as a catalyst for the production of immune cells during early development. In mouse experiments, nursing mothers fed a TVA-enriched diet passed the nutrient to their pups, which increased the production of CD4+ T cells. These cells are critical for adaptive immunity.

According to Jing Chen, PhD, a professor of medicine at UChicago and senior author of the study, the nutrient reprograms immune cells to favor fighting microbes and pathogens over responding to antigens. This shift allows the immune system to react faster. Mice raised on TVA-enriched milk showed higher survival rates when exposed to Salmonella or the flu virus, even after they reached adulthood.

Did you know? The human body cannot produce TVA on its own. It must be obtained through the diet, specifically from meat and dairy produced by grazing animals like sheep and cows.

How does breastfeeding differ from pregnancy in TVA delivery?

The timing of TVA exposure is the deciding factor in immune imprinting. The UChicago team discovered that exposure during pregnancy alone does not provide the same protective benefits as exposure during breastfeeding.

Researchers tested pups that received TVA via the mother’s diet during pregnancy but were then nursed by foster mothers on a standard diet. These pups did not show improved responses to infection. Chen stated that only postnatal exposure through breastfeeding is necessary to train neonatal T cells.

This distinction suggests a specific window of biological vulnerability and opportunity. While prenatal nutrition is vital, the “imprinting” effect on the immune system occurs specifically during the nursing phase.

What are the clinical implications for premature infants?

The research extends beyond animal models to human clinical data. Working with the UChicago Center for the Science of Early Trajectories (SET), researchers analyzed blood and breast milk samples from human mothers and infants.

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The team found a direct correlation between high TVA levels in breast milk and high TVA levels in infant blood. In preterm infants, these levels were linked to a reduced risk of bronchopulmonary dysplasia. According to the study, this chronic inflammatory lung disease often affects premature infants with underdeveloped lungs, making them more susceptible to respiratory infections.

This link provides a concrete example of how a single dietary component in breast milk can influence a specific clinical outcome in high-risk neonatal populations.

Pro Tip: For those researching infant nutrition, look for the role of “long-chain fatty acids.” These are the building blocks that often drive the epigenetic changes mentioned in the Science report.

What happens next for infant nutrition and formula?

The discovery of TVA’s impact opens the door for targeted nutritional interventions. Chen suggests that future research could explore supplementing the diets of pregnant and breastfeeding women with TVA or adding the fatty acid to infant formula to mimic the benefits of breast milk.

This is part of a larger effort to decode the complexity of breast milk. Chen noted that there are nearly 40 different fatty acids and hundreds of other components in human milk. The team intends to investigate other nutrients to see if they trigger similar long-term immune responses.

The study’s use of RNA sequencing and epigenetic analysis, led by Chuan He, PhD, provides a roadmap for identifying other “imprinting” molecules that could be used to prevent chronic inflammatory diseases in newborns.

Frequently Asked Questions

What is trans-vaccenic acid (TVA)?

TVA is a naturally occurring long-chain trans fatty acid found in the milk and meat of grass-fed animals. Unlike industrial trans fats, TVA is a nutrient found naturally in human breast milk.

Can TVA be replaced by prenatal vitamins?

According to the UChicago study, prenatal exposure is not sufficient for immune imprinting. The benefits were only observed when TVA was delivered postnatally through breastfeeding.

Does TVA help adults?

While the current focus is on neonatal development, a 2023 study by Chen’s team found that TVA improves the ability of CD8+ T cells to infiltrate and kill cancer cells in adult mice.

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