Babies’ gut bacteria may influence future emotional health

(Press-News.org) A child’s early gut microbiome may influence their risk of developing depression, anxiety or other internalizing symptoms in middle childhood, according to a new UCLA Health study. The effect appears to be related to the way bacteria are linked to communication across emotion-related brain networks. 

Published in the journal Nature Communications, the observational study found that young children whose gut microbiome had higher representation of bacteria in the Clostridiales order and Lachnospiraceae family were at higher risk of experiencing internalizing symptoms — an umbrella term that includes symptoms of depression and anxiety — in middle childhood. The connection appeared to work indirectly: the early microbiome composition was associated with differences in connectivity across different emotion-related brain networks that was linked to anxiety and depression later in childhood.  

The findings suggest that early gut bacteria could play a role in programming brain circuits tied to emotional health in later childhood. If unaddressed, symptoms of depression and anxiety can carry a higher risk of mental health challenges persisting as children develop into adolescence and adulthood, said study senior author Dr. Bridget Callaghan at UCLA. 

“By linking early-life microbiome patterns with brain connectivity and later symptoms of anxiety and depression, our study provides early evidence that gut microbes could help shape mental health during the critical school-age years,” said Callaghan, associate professor of Psychology and Bernice Wenzel and Wendell Jeffrey Term Endowed Chair in Developmental Psychology at UCLA. 

Previous research into the gut-brain axis in children has mostly focused on infants and toddlers rather than school-aged children. These studies typically examined how microbial composition may relate to early brain development involved in movement, language, and learning rather than mental health.  

Callaghan and her team sought to determine whether the makeup of a young child’s gut microbiome could have a cascading effect on mental health outcomes in later childhood, when issues such as depression and anxiety first appear. 

The study is based on data collected from the Growing Up in Singapore Towards Healthy Outcomes, or GUSTO, study. The longitudinal birth cohort study collected various health data from children in Singapore including stool samples at age 2 years, resting state MRI brain scans at age 6 years, and survey data from caregivers about the children’s behavioral problems at age 7 ½ years. The UCLA Health study utilized data from 55 of the participants in the GUSTO study. 

The UCLA study conducted a statistical analysis on the data to identify combinations of brain connectivity patterns at age 6 years that were most strongly associated with internalizing symptoms reported at age 7 ½ years. Researchers then examined how early gut microbial profiles at age 2 years were linked to those brain patterns.  

The association between internalizing symptoms and bugs within Clostridiales and Lachnospiraceae microbe populations paralleled similar research into the microbiome and adult mental health. Callaghan said these two microbe groups have been linked to stress response and depression in adults as well as to effects of early childhood adversity. Some microbes in these populations may potentially be more sensitive to stressors, which could explain their association with the development of internalizing symptoms in later childhood. 

Callaghan said future experimental research will reveal whether these associations are causal and should be acted on.  

“We need to figure out what species within these larger groups are driving the findings. Once we have that information, there are relatively straightforward ways to change the microbiome, like probiotics or diet, that we could use to address issues,” said Callaghan, who is also a member of the Goodman-Luskin Microbiome Center at UCLA Health. 

Drs. Francesca Querdasi and Jessica Uy are co-first authors of the study. Dr. Jennifer S. Labus of UCLA Health is a contributing author. The study is in collaboration with the Agency for Science, Technology and Research’s (A*STAR) Institute for Human Development and Potential, KK Women’s and Children’s Hospital, National University Health System (NUHS) and National University of Singapore Yong Loo Lin School of Medicine. 

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