Breast Milk Contributes Significantly to Babies' Bacteria

Thirty percent of bacteria found in babies' guts came from mothers' milk, a study finds.

Written byAshley P. Taylor
| 2 min read

Register for free to listen to this article
Listen with Speechify
0:00
2:00
Share

PIXABAY, WERBEFABRIKThe importance of delivery method for the development of babies’ gut bacteria has come into question in recent months. A new study from University of California, Los Angeles, reports how another aspect of newborn life influences the nascent gut microbiome: breastfeeding. The study, published Monday (May 8) in JAMA Pediatrics, found that 30 percent of babies’ gut bacteria seem to come from the mother’s breast milk and that another 10 percent can be traced to skin around the mother’s nipple.

“Breast milk is this amazing liquid that, through millions of years of evolution, has evolved to make babies healthy, particularly their immune systems,” UCLA’s Grace Aldrovandi, the study’s lead author, said in a press release. “Our research identifies a new mechanism that contributes to building stronger, healthier babies.”

In 107 mother-infant pairs, the study examined the microbial content of the mother’s milk, the skin around the mother’s nipple, and the baby’s stool, whose bacteria represent those of the gut. As Reuters reported, the bacteria in infants’ poop were more similar to the microbes from their own mothers than those from other mothers in the study, suggesting that the bacteria are transferred from mother to child through breastfeeding.

This study did not examine baby health. However, ...

Interested in reading more?

Become a Member of

The Scientist Logo
Receive full access to more than 35 years of archives, as well as TS Digest, digital editions of The Scientist, feature stories, and much more!
Already a member? Login Here

Related Topics

Meet the Author

Share
Illustration of a developing fetus surrounded by a clear fluid with a subtle yellow tinge, representing amniotic fluid.
January 2026, Issue 1

What Is the Amniotic Fluid Composed of?

The liquid world of fetal development provides a rich source of nutrition and protection tailored to meet the needs of the growing fetus.

View this Issue
Skip the Wait for Protein Stability Data with Aunty

Skip the Wait for Protein Stability Data with Aunty

Unchained Labs
Graphic of three DNA helices in various colors

An Automated DNA-to-Data Framework for Production-Scale Sequencing

illumina
Exploring Cellular Organization with Spatial Proteomics

Exploring Cellular Organization with Spatial Proteomics

Abstract illustration of spheres with multiple layers, representing endoderm, ectoderm, and mesoderm derived organoids

Organoid Origins and How to Grow Them

Thermo Fisher Logo

Products

Brandtech Logo

BRANDTECH Scientific Introduces the Transferpette® pro Micropipette: A New Twist on Comfort and Control

Biotium Logo

Biotium Launches GlycoLiner™ Cell Surface Glycoprotein Labeling Kits for Rapid and Selective Cell Surface Imaging

Colorful abstract spiral dot pattern on a black background

Thermo Scientific X and S Series General Purpose Centrifuges

Thermo Fisher Logo
Abstract background with red and blue laser lights

VANTAstar Flexible microplate reader with simplified workflows

BMG LABTECH