The study, published in the journal Beneficial Microbes, provides preliminary evidence that Streptococcus thermophilus TCI633 had “a modest effect” on mothers’ and infants’ microbiota and breast milk composition.
“Although effects on core microbial composition were minimal, the detection of TCI633-specific gene fragments in infant feces warrants further investigation into the biological relevance and potential functional role of probiotic-microbiota interactions in maternal-infant health,” wrote researchers from National Taiwan University Hospital and other institutions in Taiwan.
Streptococcus thermophilus TCI633 is a strain of bacteria isolated from human breast milk and designated Generally Recognized as Safe (GRAS).
The bacterium is well-known for its use in producing fermented foods, where it generates lactic acid and superoxide dismutase (SOD), which may help reduce oxidative stress and inflammation.
“By modulating the gut environment and influencing host immune responses, S. thermophilus may contribute indirectly to breast tissue homeostasis and bioactive milk composition,” the researchers wrote, explaining that it made a “promising candidate” for their investigations into the gut-breast axis.
The gut-breast axis
The gut-breast axis is a proposed pathway linking the maternal microbiome to the composition of breast milk and infant health.
A 2021 review described the gut-breast axis as playing “a paramount role in our existence as a species, serving as a pivotal node interacting with any other human axis and programming health for life.”
According to the review, the array of nutrients and bioactive components in breast milk act via all the body axes (gut‒brain and gut‒elsewhere axes, hypothalamic–pituitary–adrenal (HPA) axis) “intervening in their programming and function.”
The axis starts with the mother’s gut microbiota, which interacts with the infant’s gut microbiome via breastfeeding. The active ingredients in breast milk, such as HMOs, vitamins and fatty acids, help to promote immune tolerance and affect growth, development and long-term health.
“This axis is thought to function through immune-mediated signaling and microbial metabolite transport, allowing gut-residing microbes or their microbial metabolites to influence breast milk constituents,” the researchers on the current study wrote.
Study details
The double-blind, placebo-controlled, randomized trial involved 30 mother-infant pairs who were breastfeeding.
The mothers consumed the S. thermophilus TCI633 probiotic formulation daily for one month. Researchers analyzed breast milk, maternal feces and infant fecal samples to determine their microbiota composition.
“Results showed minor changes in the microbiota composition of breast milk and fecal samples in the TCI633 group, with a slight increase in S. thermophilus abundance,” they wrote.
“Furthermore, TCI633-specific gene fragments were detected in 66.7% of infant fecal samples, suggesting potential microbial transfer and colonization.”
They called for further research to determine the functional significance of their findings.
Source: Beneficial Microbes. doi: 10.1163/18762891-bja00082. “Gut-breast axis modulation through Streptococcus thermophilus TCI633 supplementation: a study on mother-infant microbiome dynamics”. Authors: C. Chen et al.