Breastfeeding vs infant formula: How does infant feeding impact a baby’s ORAL MICROBIOME?

Toni Harman
7 min readOct 23, 2023

New review study highlights how mode of feeding (breastfeeding vs infant formula), amongst other factors, affects the infant oral microbiome.

Parenting info: Breastfeeding vs infant formula — how does infant feeding impact a baby’s oral microbiome?
Parenting info: Breastfeeding vs infant formula — how does infant feeding impact a baby’s oral microbiome? Dive deeper into the science of breast milk with 7 top lactation scientists. Find out more:

Quick facts about the oral cavity, aka “the mouth”:

  • It’s the first part of the gastrointestinal tract.
  • It’s the second most diverse microbiome part of the human body.
  • It’s the necessary transition point for any food or drink entering the body.
  • And it’s also a potential biomarker for overall health.

Now a new review study shines a light into how breastfeeding vs formula-feeding, plus other early life factors, affect the development of the infant oral microbiome — AKA — the “seeding and feeding” of the microbiome in a baby’s mouth.

The review summaries recent research highlighting differences in the oral microbiomes of exclusively breastfed vs formula-fed babies.

These differences are apparent within just 48 hours of a baby being born.

The review by Arishi R.A. et al., was published in Front Microbiol. 7th Sept 2023.

Read on below for more details about the new study… and my take-home message.

About The Infant Microbiome:

If you’ve read some of my other blog-posts about the “seeding and feeding” of the infant microbiome (and why it’s so important), you’ll know this:

The microbes in breast milk PLUS the special indigestible sugars (human milk oligosaccharides) in breast milk help to shape the infant gut microbiome.

But what about the infant ORAL microbiome?

Do the microbes and special sugars in breast milk also help to shape the community of microbes living in the baby’s mouth?

Before we get to that, here are some of the things I found really interesting about the changing dynamics of the oral microbiome in early-life, as summarised in the recent review study:

How The Infant Oral…



Toni Harman

I help parents and health professionals better understand the science of pregnancy, birth, breastfeeding and the microbiome.