An Australian study published in PLOS ONE reveals that the dietary inflammatory status of exclusively breastfeeding mothers shows a significant inverse correlation with monocyte chemoattractant protein-1 levels in human breast milk, highlighting how maternal food intake may subtly influence specific infant immune signals.
Investigating Maternal Diet and Breast Milk Inflammation
The foods that breastfeeding mothers eat may subtly influence the immune composition of their breast milk, according to a new Australian study investigating inflammatory markers in human human milk. Human breast milk functions as a complex bioactive fluid containing several vital components necessary for infant growth and development, including protein, fat, growth factors, immune components, human milk oligosaccharides, and microorganisms.
In addition to promoting neurological and cognitive development, breast milk supports the development of innate immunity in infants through cytokines and chemokines, signaling molecules with pro- or anti-inflammatory properties. While it remains well known that maternal diet influences breast milk composition, researchers noted it was previously unclear whether maternal dietary patterns influence the concentrations of inflammatory markers such as chemokines and cytokines in breast milk.
To explore this relationship, researchers from the University of the Sunshine Coast assessed the inflammatory status of the diets of lactating mothers and measured the concentrations of 13 inflammatory markers in their breast milk samples.
Cohort Characteristics and Dietary Inflammatory Index Findings
The study included a total of 101 exclusively breastfeeding mothers who were at 3 to 4 months following the delivery of healthy full-term infants. Investigators assessed the inflammatory status of the maternal diet using the Dietary Inflammatory Index, an evidence-based tool designed to quantify the inflammatory potential of a person’s diet based on 45 food parameters.
Thirteen inflammatory markers were quantified in the collected samples using flow cytometric bead array. Dietary analysis revealed that all participants consumed an overall anti-inflammatory diet. Specifically, dietary fiber, beta-carotene, and vitamin E exerted the strongest anti-inflammatory effects among the cohort.
Overall, food intake among participants was generally consistent with national dietary guidelines for lactating women, though certain nutrients, such as total energy intake, fell below recommended levels. Quantification of inflammatory markers displayed substantial variability in detection rates among participants, with only a small subset of the tested markers consistently detected in the samples.
Chemokine Dominance and Specific Marker Correlations
Among the 13 tested markers, three specific chemokines were present at the highest concentrations and detected in more than 96% of breast milk samples. These included interferon gamma-induced protein-10, monocyte chemoattractant protein-1, and interleukin 8.
Correlation analysis between the quantified inflammatory markers and Dietary Inflammatory Index scores revealed a weak but significant inverse correlation for monocyte chemoattractant protein-1. None of the other twelve tested markers showed a statistically significant association with the index scores.
This chemokine-dominant profile reflects the role of breast milk in supporting neonatal immune development, particularly through chemotactic signaling and immune cell recruitment at mucosal surfaces. Rather than indicating harmful inflammation, the pattern may represent a functional and physiologically appropriate immune signal tailored to the infant gut.
Broader Implications for Infant Microbiota and Immunity
The findings build upon a broader understanding of how early biological transfer shapes infant health. Breast milk serves as a specialized secretion where the maternal immune response is highly targeted against microorganisms in the gut and airway, providing essential defense against the same pathogens likely encountered by the infant.
Beyond immune markers, breast milk comprises several hundred bacterial species and harbors bacteria at concentrations of approximately 1,000 colony-forming units per milliliter. It is estimated that breastfed infants ingest up to 800,000 bacteria daily, establishing breast milk as an immediate source of microbes seeding the infant gut following birth.
During the first month of life, infants who primarily breastfeed share 28% of their stool microbes with their mother’s milk microbes, with sharing frequency increasing in a dose-dependent manner based on daily breast milk intake. Alongside human milk oligosaccharides and extracellular vesicles, these components highlight the intricate mechanisms governing early immune and metabolic homeostasis.
