by University of Alberta Faculty of Medicine & Dentistry
A
University of Alberta-led research study followed more than 400 infants
from the CHILD Cohort Study (CHILD) at its Edmonton site. Boys at one
year of age with a gut bacterial composition that was high in the
bacteria Bacteroidetes were found to have more advanced cognition and
language skills one year later. The finding was specific to male
children.
"It's
well known that female children score higher (at early ages),
especially in cognition and language," said Anita Kozyrskyj, a professor
of pediatrics at the U of A and principal investigator of the SyMBIOTA
(Synergy in Microbiota) laboratory. "But when it comes to gut microbial
composition, it was the male infants where we saw this obvious connection between the Bacteroidetes and the improved scores."
"The
differences between male and female gut microbiota are very subtle, but
we do know from CHILD Cohort Study data that girls at early ages are
more likely to have more of these Bacteroidetes. So perhaps most girls
have a sufficient number of Bacteroidetes and that's why they have
improved scores over boys," added Kozyrskyj.
The
researchers, led by Kozyrskyj and associate professor of pediatrics
Piush Mandhane, studied bacteria found in fecal samples from the infants and
identified three different groups exhibiting similar dominant clusters
of bacteria. They then evaluated the infants on a variety of neural
developmental scales. Of those groups, only the male infants with
Bacteroidetes-dominant bacteria showed signs of enhanced
neurodevelopment.
The research replicates similar findings from a U.S. study that also showed an association between Bacteroidetes and neural development.
According
to Kozyrskyj, Bacteroidetes are one of a very few bacteria that produce
metabolites called sphingolipids, which are instrumental for the
formation and structure of neurons in the brain.
"It
makes sense that if you have more of these microbes and they produce
more sphingolipids, then you should see some improvement in terms of the
formation of neuron connections in our brain and improved scores in
cognition and language," she said.
According
to Kozyrskyj, cesarean birth is one factor that can significantly
deplete Bacteroidetes. Factors that positively influence gut microbiota
composition in infants include breastfeeding, having a high-fiber diet,
living with a dog and being exposed to nature and green spaces.
While
the findings don't necessarily mean children with a lower proportion of
Bacteroidetes will remain behind their peers in later childhood or
adulthood, the researchers believe the study offers early promise as a
way to potentially identify children at risk of neurodevelopmental
disorders.
The
team will continue to follow the infants participating in CHILD to
determine whether the findings can be predictive of autism or attention
deficit/hyperactivity disorder. Moving forward, the researchers are also
examining several other factors that may have an impact on
neurodevelopment in infants, including stress and gut colonization by
the bacterium Clostridium difficile.
"Over
the first one to two years of life, your brain is very malleable," said
Kozyrskyj. "Now we're seeing a connection between its malleability and
gut microbiota, and I think that is very important."
The
study, "Bacteroides-dominant gut microbiome of late infancy is
associated with enhanced neurodevelopment," was published in the journal Gut Microbes.
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