New research shines a light on how the gut microbiome is established from birth to age 5.

A new study published in the journal Cell Host & Microbe found that the gut microbiome of children followed similar trajectories - but at different speeds.

The study:

Roswall J. et al (March 31, 2021) looked at the gut microbiome of 471 children from Sweden.

  • Samples were collected at age 4 and 12 months, and at 3 years and 5 years old.
  • Samples were also collected from their mothers.
  • The samples were analysed using 16S rRNA gene profiling.
  • The microbial profiles were then compared to the adult Swedish population.

The findings:

To quote from the paper:

"Genera follow 4 different colonization patterns during establishment where Methanobrevibacter and Christensenellaceae colonize late and do not reached adult levels at 5 years."

Here are some of the findings:

  • The gut microbiome of children mature along similar trajectories, but at different speeds.

  • At the age of 4 months, the gut microbiome of babies born by C-section was less diverse compared to vaginally born babies.

  • By age 3-5 years old, the effect of C-section is "normalised" - so the gut microbiome of a child born by C-section is broadly in line with a child born vaginally

  • By age 5, the gut microbiome has not yet reached the full complexity of an adult

This means seem to children have "individual dynamics" in the development trajectory of their gut microbiome.

The research also found children born by C-section had a less diverse infant gut microbiome at age 4 months, but by age of 3-5 years olf, their gut microbiome is broadly similar to children born vaginally.

The study also shows that it takes up to 5 years for the mature intestinal microbiota to become established.

My take-home message:

Regarding the subject of the "normalised" gut microbiome of a 3-5 year old child born by C-section....

As our Microbirth film and Infant Microbiome course reveals, scientists believe that critical infant immune training happens in the first few days, weeks, and months after birth.

Even though the gut microbiome follow similar trajectories up until age 5, a critical part of the immune training might already have happened in the first part of life.

Children born by C-section, or exposed to antobiotics or formula fed - all of these things might have affected the optimal "seeding and feeding" of the infant gut. In turn, this could have affected optimal immune training, which could increase the likelihood of a child developing a non-communicable disease later in life.


Article and science reference:

Article: Easy-to-understand article in Science Daily:

Science reference: Josefine Roswall, Lisa M. Olsson, Petia Kovatcheva-Datchary, Staffan Nilsson, Valentina Tremaroli, Marie-Christine Simon, Pia Kiilerich, Rozita Akrami, Manuela Krämer, Mathias Uhlén, Anders Gummesson, Karsten Kristiansen, Jovanna Dahlgren, Fredrik Bäckhed. Developmental trajectory of the healthy human gut microbiota during the first 5 years of life. Cell Host & Microbe, 2021; DOI: 10.1016/j.chom.2021.02.021


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