link gut bacteria and child behaviour
Jenn Ryan
Jenn Ryan
January 16, 2024 ·  5 min read

Gut Bacteria and Your Kid’s Behavior: Research Sheds Light on a Link

We know that gut bacteria can play an influential in our health and even our behavior, but new research is highlighting the potential role of our gut microbiomes in children’s behavior.

A study from Ohio State University looked at the stool samples of 77 children ranging from 18 to 27 months of age, and what they found was a bit surprising [1]. Children who had a more diverse range of gut bacteria tended to be more extroverted, as well as curious, sociable, and impulsive.

One of the authors of the study, Dr. Michael Bailey, said, “There is definitely communication between bacteria in the gut and the brain, but we don’t know which one starts the conversation. Maybe kids who are more outgoing have fewer stress hormones impacting their gut than shy kids. Or maybe the bacteria are helping mitigate the production of stress hormones when the child encounters something new. It could be a combination of both.”

In other words, the study is far from conclusive. But gut bacteria, sometimes referred to collectively as the gut microbiome, have been tentatively linked to everything from digestion to the immune system. Previous research, as we’ll soon see, has also linked gut microbiome to behavior.

What Is Gut Microbiome and What Potential Effects Does It Have?

The bacteria in our guts have been getting a lot of attention lately, and a growing body of research is showing that that attention isn’t entirely unwarranted.

Defined as “the totality of microorganisms, bacteria, viruses, protozoa, and fungi, and their collective genetic material” in the gastrointestinal tract, gut microbiomes play an essential role in nutrient and mineral absorption, and are even suspected to aid the immune system [2].

The gut microbiome tends to be more fluid in infancy but then stabilizes in childhood, and “have a great impact” on the development of the digestive system and the immune system, and could even potentially “be a main determinant of life-long health” [3].

However, these bacteria can be influenced by diet, drugs, and other environmental factors [4]. In other words, the bacteria can change and aren’t entirely stable. They’ve been suspected to play a role in anxiety, cognition, and even pain. Probiotics—microorganisms that promote healthy gut bacteria—even have the potential to treat allergenic reactions, infections, and irritable bowel syndrome [5].

It’s hard to ignore the growing relevance of gut bacteria on our health. Here’s what else research has to say about gut microbiome and behavior.

There’s quite a list of additional research that has linked the state of our gut microbiome to our mood and behavior. Here are just a few studies that highlight the connection between the brain and our gut.

  • Married couples who fight are at higher risk for leaky gut. Ohio State University published another study that showed that married couples who have bad fights are more likely to suffer from leaky gut, which is a prime example of how environmental factors can influence gut microbiome.

The study showed that martial distress could lead to gut inflammation and even illness for some people, according to the lead author of this study. It makes you think about how events more traumatic than martial fights can potentially disrupt our gut bacteria!

  • Less diverse gut bacteria and depression. Other research shows a correlation between certain reduced groups of gut bacteria and people with depression, which could point to a possible link between less diverse gut bacteria and mental health disorders [7].
  • Gut bacteria influence brain matter. Although researchers are still understanding the link, we do know that gut bacteria interact with the brain to influence mood and behavior, including emotional, attentional, and sensory processing regions in the brain [8]. 
  • Important neurotransmitters are affected by the gut microbiome. Other data shows that bacteria produce neurotransmitters such as GABA (which can promote sleep and reduce stress and anxiety) and serotonin which can impact the brain [9], [10].

It goes without saying that our guts are influential in our health, although the degree to which they affect behavior and physical health is still being investigated!

Future Steps Based on This Information

According to Dr. Lisa Christian, another author of the study from Ohio State University, by about two years of age, the gut microbiome is relatively stable and a child’s temperament is a good predictor of future behavior [1].

“It is possible that effects of diet would emerge if we used a more detailed assessment. It is certainly possible that the types or quantities of food that children with different temperaments choose to eat affect their microbiome.”

Dr. Christian says it could be possible to alter the microbiome to influence health and behavior in childhood, when the bacteria might be more responsive to change. Dr. Christian says the next steps would be to find out whether these behaviors continue into the child’s development, namely adolescence, and whether the manipulation of gut microbiome through diet could be beneficial.

But could these findings support a future diet that would encourage a healthy digestive and immune system development, while potentially avoiding the terrible twos? It seems promising. Even research from 20 years ago found that diet could “dramatically” influence children’s behavior, including consuming foods that have synthetic dyes and even foods such as milk and corn [11].

While we wait for studies to catch up with suspected findings, it seems like the best thing to do is ensure our children eat healthy foods from day one, and as they grow, encourage them to make healthy choices that could just support their physical and mental health for a lifetime.