Early-life interactions between human milk feeding and certain bacteria in the gut microbiome are associated with faecal metabolome and childhood systolic blood pressure, according to a large cohort study, underscoring the potential importance of early nutrition–microbe interplay for cardiometabolic health.

Childhood hypertension is an increasingly recognised public health concern, with evidence showing that elevated blood pressure tracks from early life into adulthood.

Human milk feeding and the infant gut microbiome are modifiable early-life factors associated with cardiometabolic outcomes, but their combined influence on childhood blood pressure remains poorly understood.

Therefore, an analysis of research conducted as part of the Canadian Healthy Infant Longitudinal Development study and published in JAMA Network Open, investigated whether human milk feeding interacts with the infant gut microbiome in relation to infant faecal metabolites and childhood systolic blood pressure.

The cohort included 1,324 children born at 35 weeks’ gestation or later without major congenital abnormalities. Of these, 610 (46.1%) were girls, and 982 (74.2%) were delivered vaginally.

Human milk feeding status was assessed at three months of age and again at one year. Infant gut microbiome composition and faecal metabolites were measured at these same time points using metagenomic sequencing and targeted metabolomics.

At three months, 60.4% of infants were exclusively fed human milk, and 26.4% received mixed feeding, while 47.3% were receiving any human milk at one year.

Childhood systolic blood pressure was measured at approximately three and five years of age and expressed as age-, sex- and height-specific percentiles.

Bifidobacteria play key role in systolic blood pressure

At three months of age, but not at one year, human milk feeding and the presence of Bifidobacterium longum subsp. infantis (B. infantis) and other milk-degrading microbes were associated with systolic blood pressure and faecal metabolites.

Among infants with B. infantis at three months, mixed feeding was associated with a 14.8-percentile lower systolic blood pressure (95% CI −27.1 to −2.6), while exclusive human milk feeding was associated with a 17.2-percentile lower systolic blood pressure (95% CI −29.5 to −4.8), compared with infants not fed human milk. No comparable association was observed in infants lacking B. infantis.

Several other gut microbes, including Eggerthella lenta and Veillonella dispar, also showed feeding-dependent associations with childhood systolic blood pressure. Additionally, 20 faecal metabolites at three months and 11 at one year were associated with systolic blood pressure, with patterns varying according to feeding status and microbial composition.

The authors noted that blood pressure was typically measured only once at each childhood visit, potentially introducing measurement error. As an observational study, causal inference was limited, despite extensive adjustment for maternal and child confounders. As the cohort was relatively highly educated, generalisability to more socioeconomically varied populations might be limited, they added.

Implications and future directions

The findings support the hypothesis that early colonisation by specific milk-degrading microbes, particularly B. infantis, enhances the systolic blood pressure-lowering associations of human milk.

The authors concluded that optimising early-life nutrition–microbiome interactions could be a future strategy for precision nutrition and early cardiovascular disease prevention, but cautioned that factors arising after infancy, such as later diet, may modify these associations and warrant further study.

Reference

Liu T et al. Human Milk and Infant Gut Microbiome in Association With Infant Fecal Metabolome and Child Blood Pressure. JAMA Netw Open 2026;9(2):e2559385.