Babies’ Gut Bacteria May Influence Their Future Emotional Health

A child’s early gut microbiome may influence their risk of developing depression, anxiety or other internalized symptoms during childhood, according to a new study from UCLA Health. This effect appears to be linked to how bacteria are linked to communication through emotion-related brain networks.

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

The findings suggest that early gut bacteria may play a role in programming brain circuits linked to emotional health later in childhood. If left untreated, symptoms of depression and anxiety can lead to a higher risk of continuing mental health problems as children develop into adolescence and adulthood, said lead study author Dr. Bridget Callaghan of UCLA.

“By linking microbiome patterns early in life to brain connectivity and later symptoms of anxiety and depression, our study provides early evidence that gut microbes may help shape mental health during 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 on the gut-brain axis in children has primarily focused on infants and toddlers rather than school-age children. These studies generally examined the link between microbial composition and early brain development involved in movement, language and learning rather than mental health.

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

The study is based on data collected through the Growing Up in Singapore Towards Healthy Outcomes (GUSTO) study. The Longitudinal Birth Cohort Study collected various health data from Singapore children, including stool samples at age 2 years, resting brain MRI scans at age 6 years, and caregiver survey data on children’s behavioral problems at age 7.5 years. The UCLA Health study used data from 55 of the GUSTO study participants.

The UCLA study conducted a statistical analysis of the data to identify the combinations of brain connectivity patterns at age 6 that were most strongly associated with internalizing symptoms reported at age 7.5. The researchers then examined how early gut microbial profiles at age 2 related to these brain patterns.

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

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

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