The gut. It's a topic that comes up more and more often in the context of difficulties such as mood swings or concentration problems in children. It is increasingly discussed not just in terms of digestion, but also overall wellbeing. Just a few years ago, this connection might have seemed surprising. Today, however, we know that the role of the digestive tract doesn't end with digestion.
The gut is one of the most biologically active organs in the body. It participates in regulating immunity, metabolic processes, and communication with the nervous system. What's more, its functioning also affects wellbeing and emotional regulation. In other words, the state of a child's gut can matter for their overall wellbeing and day-to-day functioning.
This doesn't mean, however, that emotional difficulties "start in the gut." A child's behavior is influenced by many factors — relationships, environment, sleep quality, temperament, or developmental stage. Communication between the gut and the brain is just one (albeit important!) piece of this puzzle.
The key to understanding this relationship is a mechanism known as the gut–brain axis.
The gut–brain axis is a two-way communication system between the digestive tract and the brain. It includes signals transmitted via the nervous system (whose main physical information highway is the vagus nerve), the immune system, the hormonal system, and the gut microbiota.
It can be pictured as a network of connections in which the gut and brain are constantly exchanging information about what's happening in the body.
The gut–brain axis is currently being studied intensively. In one recent research review, scientists point out that the gut microbiota may play an important role in the development of the nervous system and in regulating emotions and stress responses in children. At the same time, they stress that these mechanisms are highly complex and still require further research.
How Can the Gut Affect a Child's Wellbeing?
Researchers point to several mechanisms that may explain why the condition of the digestive tract affects the functioning of the whole body.
First — the gut microbiota, meaning the collection of microorganisms living in the digestive tract. Gut bacteria are involved, among other things, in regulating the immune system, producing metabolites, and communicating with the nervous system. It is in the gut that the vast majority of serotonin (the so-called "happiness hormone") is produced, along with neurotransmitters such as dopamine and the calming GABA. In addition, beneficial bacteria produce short-chain fatty acids (SCFAs, e.g. butyric acid), which nourish the intestinal lining and have a protective effect on the brain. Disruption of the bacterial balance — so-called gut dysbiosis — can directly lead to a shortage of these substances and a decline in mood.
Second — inflammation. Chronic inflammatory processes are now studied not only in the context of metabolic disease but also in relation to brain function and wellbeing. The gut plays a significant role here, since a substantial portion of the immune system's cells are located in the digestive tract. This kind of chronic, low-grade inflammation, often resulting from a "leaky" intestinal barrier, frequently manifests in children as irritability and so-called brain fog.
And finally — metabolic stability. Large fluctuations in blood glucose levels can affect energy levels, concentration, and emotional regulation. As a dietitian, I often observe this in children who consume excess simple sugars and highly processed foods — sudden insulin surges followed by blood sugar drops (reactive hypoglycemia) are a direct route to irritability, trouble focusing, and chronic fatigue.
Interestingly, similar relationships are also being examined in the context of children's cognitive development. In a study published in 2023, researchers analyzed the microbiome composition of 165 healthy children aged 6–9 and observed significant associations between gut microbiota diversity and cognitive test results. The authors note, however, that the study does not prove a cause-and-effect relationship, but it does add to the evidence that the gut and brain may be strongly linked.
This may also be one of the reasons why we so often feel stress "in the gut." A growing body of evidence suggests that this relationship works both ways — chronic stress can affect gut function, and the state of the gut can affect how the body responds to stress.
In practice, this obviously doesn't mean that every child with concentration difficulties has a "gut problem." The body functions as an integrated system in which individual elements influence one another. Diet, sleep, physical activity, stress levels, and daily routine don't function in isolation — much like the gut and the brain.
What Signs Might Catch a Parent's Attention?
There is no single set of symptoms that can confirm that emotional difficulties or concentration problems are caused specifically by the gut. A child's body is a complex system, and similar symptoms can have many different causes.
It is worth paying attention, however, to situations where wellbeing-related difficulties occur alongside digestive problems.
Examples of such signs include:
Interestingly, similar relationships have also been observed in scientific research. In a review published in 2025, researchers noted that children with mood disorders, anxiety, or certain neurodevelopmental difficulties more often also report digestive problems.
A Dietitian's Practice: How to Support a Child's Gut and Brain Every Day
As a clinical dietitian, I always emphasize that the strongest and most accessible tool for shaping the microbiota is our everyday plate. To effectively support a child's gut–brain axis, it's worth basing their diet on a few key pillars:
In summary: psychological or educational support for children's emotional difficulties is extremely important, but let's remember that what ends up on the plate builds the physiological foundation for proper nervous system function. A well-cared-for gut simply means a calmer mind.
Expert consultation: Dr. Hanna Stolińska, clinical dietitian
Bibliography
