Researchers Link Maternal Nutrition to Changes in Breast Milk Immune Signals

Can what a breastfeeding mother eats shape her baby's immune system? A new study suggests the answer may be yes-though the effect appears to be subtle.

A study published in PLOS ONE has found that a mother's diet may slightly influence certain immune-related components in breast milk, potentially affecting how an infant's immune system develops. However, researchers say the impact appears limited and more research is needed.

Scientists from the University of the Sunshine Coast studied 101 healthy mothers who were exclusively breastfeeding their full-term infants at 3–4 months after delivery. They assessed the inflammatory potential of each mother's diet using the Dietary Inflammatory Index (DII) and measured 13 inflammatory markers in breast milk samples.

Overall, the mothers consumed predominantly anti-inflammatory diets, with dietary fiber, beta-carotene, and vitamin E contributing most to their diet quality. Their eating patterns generally matched Australian dietary recommendations for breastfeeding women, although some consumed less energy than recommended.

Among the 13 immune markers analyzed, three chemokines—interferon gamma-induced protein-10 (IP-10), monocyte chemoattractant protein-1 (MCP-1), and interleukin-8 (IL-8)—were detected in more than 96% of breast milk samples and were present at the highest concentrations.

Researchers found that only MCP-1 showed a significant relationship with diet. Mothers with more anti-inflammatory diets tended to have slightly higher levels of this immune signaling protein, while no meaningful associations were observed for the other inflammatory markers.

Because the study involved only healthy Australian women with largely anti-inflammatory diets and relied on a single 24-hour dietary recall, the findings cannot establish cause and effect or be generalized to all populations. The researchers say larger and more diverse studies are needed to better understand how maternal diet may influence breast milk immunity and infant health.

REFERENCE: Slegers CB. (2026). Assessment of maternal diet inflammatory status and inflammatory markers in human breast milk. PLOS ONE. DOI: https://doi.org/10.1371/journal.pone.0352248.