Natural Health News — The next time your toddler acts adventurous, shy, fidgety or cuddly, the trigger could be the specific type of bacteria in his or her gut.
Researchers from Ohio State University studied microbes from the gastrointestinal tracts of children between the age of 18 and 27 months, and found that the abundance and diversity of certain bacterial species appear to impact behaviour, particularly among boys.
The correlation exists even after taking into account breastfeeding, diet and the method of childbirth – all of which are known to influence the type of microbes that populate a child’s gut.
The researchers say they weren’t looking for a way to help parents modify the ‘terrible twos,’ but for clues about how – and where – chronic illnesses like obesity, asthma, allergies and bowel disease start.
» US scientists examined the link between gut bacteria and behaviour in toddlers.
» In boys, in particular, the abundance of certain bacteria correlated with extroverted and self-confident behaviour.
» In girls an abundance of some of the same types of bacteria produced more fearful behaviour.
» Researchers as uncertain of why there is such a difference between boys and girls.
“There is substantial evidence that intestinal bacteria interact with stress hormones – the same hormones that have been implicated in chronic illnesses like obesity and asthma,” said Lisa Christian, PhD, a researcher with Ohio State’s Institute for Behavioral Medicine Research. “A toddler’s temperament gives us a good idea of how they react to stress. This information combined with an analysis of their gut microbiome could ultimately help us identify opportunities to prevent chronic health issues earlier.”
Research in adults has shown that a low diversity of gut bacteria is linked to obesity and heart disease.
Linking gut and brain
Christian and study co-author, microbiologist Michael Bailey, PhD, studied stool samples from 77 girls and boys, comparing them to questionnaires given the parents about behaviour, and found that children with the most genetically diverse types of gut bacteria more frequently exhibited behaviours related with positive mood, curiosity, sociability and impulsivity.
In boys only, they found that extroverted and self-confident personality traits were associated with the abundances of microbes from the Rikenellaceae and Ruminococcaceae families.
Overall, associations of temperament with the gut microbiome in girls were fewer and less consistent than for boys. However, in girls, behaviors like self-restraint, cuddliness and focused attention were associated with a lower diversity of gut bacteria, while girls with an abundance of Rikenellaceae appeared to experience more fear than girls with a more balanced diversity of microbes.
A wide range of ‘normal’
The average gastrointestinal tract contains 400-500 different species of bacteria. While scientists believe that the microbiome is generally set by the age of two, there are dramatic changes in gut microbes that take place during and after birth, as babies pick up bacteria from their mothers during labor and through breastfeeding. Babies born via C-section will have different microbes than babies delivered vaginally.
In this study, the associations between temperament and the gut microbiome weren’t due to differences in the diets or method of delivery, but the researchers admit that they did not delve too deeply into specific diets and that a different picture might emerge with a more detailed assessment.
The researchers advise that parents shouldn’t try to change their child’s gut microbiome just yet. Scientists still don’t know what a healthy combination looks like, or what might influence its development.
“The bacterial community in my gut is going to look different than yours – but we are both healthy. The perfect microbiome will probably vary from person to person,” said Dr. Bailey.
The research is published in the journal Brain, Behavior and Immunity.
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