The study of early school-aged children (in the age group of 5-7) showed a connection between the bacteria in their gut and their behaviour, said researchers, adding that parents play a key role in their kids' microbiome beyond the food they provide.
"Childhood is a formative period of behavioural and biological development that can be modified, for better or worse, by caregivers and the environments they help determine," said microbiology and statistics researcher Tom Sharpton Oregon State University.
"Kids' development trajectories are affected by their own genes and environmental factors, and also by the community of microbes living in, on and around their bodies," Sharpton said.
The gut microbiota features more than 10 trillion microbial cells from about 1,000 different bacterial species.
The researchers, which included scientists from Stanford University and University of Manitoba, surveyed the gut microbiomes of 40 school-aged children.
The scientists collected stool from the children and parents filled out questionnaires on socioeconomic risk, behavioural dysregulation, caregiver behavior, demography, gut-related history (like antibiotic use) and a week-long diet journal.
They used a technique known as shotgun metagenomics to apply whole-genome sequencing to all of the organisms found in the subjects' stool.
The technique gives insight into which microbes live in the gut and their functions.
"One of the novel associations we found was between Type VI secretion systems and behaviour," said Keaton Stagaman of the OSU College of Science.
Type VI is one of the secretion systems bacterial cells use to release the peptides and proteins that affect the balance of the microbial ecosystem.
The analysis showed that children with behavioural problems and higher socioeconomic stress had different microbiome profiles than those who didn't, and also that the quality of the parent-child relationship, as well as parental stress, played a role in how pronounced those differences were.
The findings, published in the journal mBio, are important because microbiome can shed light on which children are heading toward mental health challenges.
"Future studies will hopefully show whether these secretion systems have direct or indirect effects on the gut-brain axis and which organisms carry these systems," Sharpton said.
The gut-brain axis, the reciprocal communication between the enteric nervous system and mood or behaviour, is a rapidly growing and exciting body of research.
The researchers said that future work should also take a close look at the impacts of diet on the microbiome and behaviour.
( With inputs from IANS )