The Gut-Brain Connection

Exploring the Impact of Gut Health on ADHD Symptoms

ADHD symptoms include inattention, hyperactivity, and impulsivity. Research points to a potential link between gut health and ADHD symptoms. The gut and the microbiome plays a much wider role in our health than was previously understood. We now know a lot more about how imbalances in the gut may contribute to ADHD-like behaviors.

The gut contains a complex ecosystem of microorganisms known as the gut microbiome. Studies have confirmed that there is a constant, two-way conversation between the gut and the central nervous system. This is called the gut-brain axis.

ADHD Symptoms

  1. Inattention:
    • Difficulty sustaining attention in tasks or play activities
    • Easily distracted by extraneous stimuli
    • Forgetfulness in daily activities, such as forgetting to complete chores or tasks
    • Difficulty organizing tasks and activities
    • Avoidance or reluctance to engage in tasks requiring sustained mental effort
    • Frequently losing items necessary for tasks or activities (e.g., school supplies, keys)
  2. Hyperactivity:
    • Excessive fidgeting or restlessness, such as tapping hands or feet
    • Inability to remain seated when expected to do so, especially in situations where it is inappropriate (e.g., classroom, meetings)
    • Difficulty engaging in leisure activities quietly
    • Talking excessively or impulsively, often interrupting others
  3. Impulsivity:
    • Acting without consideration of potential consequences
    • Difficulty waiting for one’s turn in conversations or activities
    • Impulsive decision-making, leading to risky behaviors
    • Interrupting or intruding on others’ conversations or activities

It’s important to note that not all individuals with ADHD exhibit all symptoms, and the severity of symptoms can vary widely among individuals.

Children with ADHD and gut microbiome diversity

Research suggests that changes in the gut microbiome may influence brain function and behaviour. Several studies have reported differences in the gut microbiome of individuals with ADHD. A study published in Pediatrics found that children with ADHD had lower levels of beneficial bacteria such as Bifidobacterium and higher levels of potentially harmful bacteria such as Clostridia. Animal studies have demonstrated that changing the gut microbiome using probiotics or antibiotics changes behaviour and cognitive function.

Another study found that Children with ADHD had a larger presence of a gut microbe candida albicans. This is commonly called thrush/yeast infection. And further lab tests confirmed the association between the microbe and the risk of a leaky gut.

ADHD and Neurotransmitters

One possible mechanism underlying the gut-brain connection in ADHD involves neurotransmitter regulation. The gut various neurotransmitters, including feel good chemicals like serotonin, dopamine, and gamma-aminobutyric acid (GABA). These play crucial roles in mood regulation and cognitive function. Dysregulation of these neurotransmitter systems has been implicated in the pathophysiology of ADHD. For example, dopamine, often referred to as the “reward neurotransmitter,” is involved in attention, motivation, and impulse control. Infection or other changes in the gut bacteria can lower the bodies ability to create and use these neurotransmitters.

I work with people with severe gut issues who report symptoms resembling those of ADHD. This is because chronic gastro issues can cause inflammation. This can impact our neurotransmitters and affect mood, concentration and focus. Evidence backs this up. A study published in Frontiers in Psychiatry, found a higher level of ADHD-like symptoms in children with IBS.


Research is ongoing. Lack of bacteria diversity and imbalance has been found to increase the risk of Alzheimers and Parkinsons. But there is no evidence to suggest a direct cause between ADHD and gut bacteria. What we do know is that there is a complex interplay between the gut and the brain. That this connection means that gut bacteria, probiotics and antibiotics can impact ADHD symptoms. We improving your gut bacteria balance impacts ADHD symptoms.


  1. Cickovski T, Mathee K, Aguirre G, Tatke G, Hermida A, Narasimhan G, Stollstorff M. Attention Deficit Hyperactivity Disorder (ADHD) and the gut microbiome: An ecological perspective. PLoS One. 2023 Aug 18;18(8):e0273890. doi: 10.1371/journal.pone.0273890. PMID: 37594987; PMCID: PMC10437823.
  2. Checa-Ros A, Jeréz-Calero A, Molina-Carballo A, Campoy C, Muñoz-Hoyos A. Current Evidence on the Role of the Gut Microbiome in ADHD Pathophysiology and Therapeutic Implications. Nutrients. 2021 Jan 16;13(1):249. doi: 10.3390/nu13010249. PMID: 33467150; PMCID: PMC7830868.
  3. Pediatrics. 2019 Aug;144(2):e20190151.
  4. Frontiers in Psychiatry. 2019 Jan 17;9:715.