Bayside Chiropractic Providence, Rhode Island

01/26/2026

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01/26/2026

Human milk is magical. Now we know more about why.

Scientists Discover Breast Milk Carries Key Gut Bacteria to Infants
By University of Chicago Medical Center
January 21, 2026
Human breast milk contains its own microbial ecosystem, and new research suggests these microbes may help seed an infant’s gut.

Most discussions of breast milk highlight nutrients, antibodies, and the parent infant bond, while the microbes in milk get far less attention. Yet human milk also contains its own small microbial community, and these bacteria may help steer how a baby’s gut microbiome develops, with downstream effects on nutrient absorption, metabolism, and immune maturation.

A new study published in Nature Communications offers one of the clearest views so far of how different bacterial lineups in human milk may contribute to building infants’ gut microbiomes.

Mapping the milk microbiome

Studying the breast milk microbiome is challenging because milk is fatty and typically contains relatively few bacteria, making it hard to extract enough genetic material for detailed analysis.

“Breast milk is the recommended sole source of nutrition for an infant’s first months of life, but important questions about the milk microbiome remained unanswered because the analytical challenges are intimidating,” said first author Pamela Ferretti, PhD, a postdoctoral researcher in the Blekhman Lab at the University of Chicago. “We decided to tackle this endeavor because our collaboration presented a unique opportunity to combine key resources.”

Those resources included hundreds of milk samples collected as part of the Mothers and Infants LinKed for Healthy Growth (MILk) study, led by Ellen Demerath, PhD, at the University of Minnesota and by David Fields, PhD, at the Oklahoma University Health Sciences Center. At UChicago, Ferretti and her colleagues paired those samples with metagenomic methods and extensive experience working with microbiome datasets, including Ferretti’s specialized background in infant microbiomes and transmission analysis. In earlier work, she examined how microbes from different maternal body sites — such as mouth, skin, and vaginal cavity — contribute to the microbiomes that babies develop.

After analyzing 507 breast milk and infant stool samples from 195 mother–infant pairs, the researchers found that milk contained a characteristic mix of bacteria dominated by bifidobacteria, including Bifidobacterium longum, B. breve, and B. bifidum. More than half of the milk samples contained B. longum, and that same species was abundant in over 98% of the infants’ gut microbiomes.

“Even though B. longum is well-documented as being highly prevalent in the infant gut, it was surprising to find such a strong signature of that species in the breast milk samples because previous milk studies mostly reported other bacterial taxa like Staphylococcus and Streptococcus,” Ferretti said. “We think these results will prompt some reevaluation in the field.”

Tracing microbes from milk to the infant gut
Most prior studies analyzing bacterial DNA in breast milk used a relatively inexpensive, fast technique called amplicon sequencing, which targets a limited number of predetermined genomic regions for each experiment. This method is good for efficiently identifying species within a mixed sample, but it leaves most of the bacterial genome unexamined.

“Metagenomic analysis is trickier and more complicated, but it really paid off because it allowed us to obtain information at the level of different bacterial strains — which is key, because that’s the only level where we could actually claim to know about transmission,” Ferretti said.

The paper reported 12 instances in which the same exact strain was found in a mother’s breast milk and in the gut of her infant, which is a very strong indication that the transmission happens vertically via breastfeeding.

Some of these shared strains were beneficial commensal species such as B. longum and B. bifidum, which help digest human milk sugars and support healthy gut development. Others, however, were pathobionts — microbes like E. coli and Klebsiella pneumoniae that can live harmlessly in healthy individuals but have the potential to cause infection under certain conditions. The authors note that all mothers and infants in the study were healthy, indicating that these species’ presence in milk does not inherently signal disease but rather reflects the microbial diversity that can be transferred during breastfeeding.

Interestingly, the team also saw specific strains of bacteria usually associated with the mouth — such as Streptococcus salivarius and Veillonella species — in milk samples. They realized this as potential evidence of “retrograde flow” during breastfeeding: as the baby feeds, tiny amounts of oral bacteria may travel back into the ni**le and ducts and become part of the milk microbiome.

Expanding human milk research
Ferretti noted that the study not only sheds light on microbial transmission but also fills a major gap in available data for scientists studying early-life health.

“This study nearly doubled the number of metagenomic breast milk samples that are publicly available, and pairs them with extensive information on mothers’ health and lifestyle,” Ferretti said. “We’re hopeful that our findings and future analyses that use this dataset will really push the field forward.”

In subsequent studies, the researchers hope to take their analysis to the next level with a multi-omic approach, including analyzing metabolites like human milk oligosaccharides (HMOs) and examining the “exposome” of environmental factors like PFAS and antimicrobial resistance that can be passed along through milk.

“Ultimately, we’re interested in looking at longer health trajectories to see if factors in breast milk and early life are predictive of health outcomes later in life,” Ferretti said.

Reference: “Assembly of the infant gut microbiome and resistome are linked to bacterial strains in mother’s milk” by Pamela Ferretti, Mattea Allert, Kelsey E. Johnson, Marco Rossi, Timothy Heisel, Sara Gonia, Dan Knights, David A. Fields, Frank W. Albert, Ellen W. Demerath, Cheryl A. Gale and Ran Blekhman, 22 November 2025, Nature Communications.
DOI: 10.1038/s41467-025-66497-y

https://scitechdaily.com/scientists-discover-breast-milk-carries-key-gut-bacteria-to-infants/

01/12/2026

Loss and miscarriage support- tomorrow (second Monday of each month)

Exciting news!!!! After many changes including hybrid during the pandemic, not only is our pregnancy and infant loss peer group back in person, but thanks to a generous grant from we will be providing attendees with light dinner and gift cards for participation. **REGISTRATION LINK IN BIO**

01/11/2026

Great opportunity for fabulous photos.

In search of 3 pregnant models at least 34 weeks pregnant, 3 families with newborn under 4 weeks old and 2 birth doulas and postpartum doulas for video and stills. Must be willing to sign a model release. People will receive 10 digital images and print release and 3 short unedited videos for personal use. Doula- I will be allowing use of images for your marketing materials.

Text with interest: (401) 497-8219

01/10/2026

Did you use a pump to help establish supply. Take a few minutes to help this research

Hi, I’m Diane DiTomasso from the University of Rhode Island College of Nursing. We’re studying how women use breast pumps to establish milk supply. If you’re over 18, gave birth to a healthy full-term infant in the past year, and used a breast pump to help bring in your milk supply, we’d love your input!
The survey takes 6–7 minutes and is anonymous.
Click here to participate: https://tinyurl.com/4auudp82
Approved by the URI Institutional Review Board.
Thank you for your time!

01/03/2026

Fabulous pregnancy and postpartum groups available now in central falls.

12/22/2025

💜 well stated.

The history of assessing and managing tongue ties has evolved significantly over time. In ancient times, midwives recognized the potential impact of tongue ties on breastfeeding, and some would manually snip the tight frenulum to improve an infant’s ability to nurse. This practice, though not widely documented, suggests an early awareness of the issue, particularly in relation to feeding. Throughout the Middle Ages and into the 19th century, there were sporadic accounts of physicians and midwives performing similar procedures, but there was little consensus on its importance

By the early 20th century, as bottle-feeding became more common, the issue of tongue ties was largely overlooked. With fewer babies breastfeeding, the need to address oral restrictions in newborns diminished, and tongue-tie treatment became a less frequently discussed medical concern. When cases were recognized, they were often only addressed if they caused obvious problems with speech or severe feeding difficulties, and treatments varied greatly depending on the practitioner

It wasn’t until the mid to late 20th century that tongue ties gained renewed attention, particularly in the realm of speech development. Concerns emerged about the possible role of restricted tongue movement in speech delays or articulation issues, and more research began to surface. However, even then, many cases of tongue tie were either underdiagnosed or not treated unless the condition was severe

In the early 2000s, the rise of breastfeeding advocacy and lactation consulting brought tongue ties back into focus. With more emphasis on the importance of breastfeeding, practitioners began to reassess the impact of tongue restrictions on nursing success. Lactation consultants and other professionals specializing in infant feeding played a key role in advocating for earlier recognition and treatment. Today emerging research helps us understand that ties can impact more than just speech. New awareness means better diagnosis and treatment