The Gut-Brain Connection: How Digestive Health Affects Behaviour and Mood
If your child struggles with anxiety, OCD, ADHD, tics or emotional regulation, you may have been told that these symptoms are purely neurological or behavioural. But emerging research tells a different story—one that connects gut health directly to brain function, mood and behaviour.
The gut and brain are deeply intertwined, and imbalances in the digestive system can lead to inflammation, neurotransmitter imbalances and immune dysfunction, all of which can impact a child’s mental and emotional well-being.
If your child experiences mood swings, meltdowns, difficulty focusing or anxiety that seems unexplained, it may be time to look at their gut health as a key factor.
What Is the Gut-Brain Connection?
The gut-brain connection refers to the constant communication between the digestive system and the brain. This happens through several pathways:
The Vagus Nerve – A direct physical connection between the gut and brain, sending signals in both directions.
Neurotransmitter Production – The gut produces key brain chemicals, such as serotonin, dopamine, and GABA, which regulate mood, focus and behaviour.
The Immune System – Around 70% of the immune system is in the gut. Inflammation or immune activation in the gut can trigger neuroinflammation affecting brain function.
The Microbiome – The trillions of bacteria in the gut influence digestion, immune balance and even emotional health.
When gut health is compromised, it can lead to behavioural challenges, emotional instability and cognitive difficulties.
How Gut Health Affects Mood and Behaviour
1. The Gut Produces Neurotransmitters That Regulate Mood
Most people think of neurotransmitters—like serotonin and dopamine—as being made in the brain. But in reality, around 90% of serotonin (the “feel-good” neurotransmitter) is produced in the gut.
If the gut is inflamed or imbalanced, neurotransmitter production can be affected, leading to:
Increased anxiety and OCD tendencies
Mood swings and emotional outbursts
Sleep disturbances
Difficulty with focus and motivation
2. Gut Inflammation Can Trigger Brain Inflammation
When the gut is irritated—due to food sensitivities, infections, toxins or poor diet—it can trigger systemic inflammation.
This inflammation does not stay in the gut. Instead, it can:
Activate the immune system in the brain, leading to neuroinflammation
Increase oxidative stress, making it harder for the brain to function properly
Exacerbate symptoms of PANS, PANDAS, ADHD and Autism
3. An Imbalanced Microbiome Affects Behaviour
The gut microbiome—made up of trillions of bacteria—plays a critical role in digestion, immune regulation and neurotransmitter production.
When beneficial bacteria are outnumbered by harmful bacteria it can contribute to:
Increased aggression, irritability and mood swings
Tics, compulsions and anxiety
Food cravings and digestive discomfort
Studies have even shown that imbalances in gut bacteria are linked to depression, anxiety and behavioural disorders in both children and adults.
Signs Your Child’s Gut Health May Be Affecting Their Brain
If your child has ongoing digestive issues and behavioural symptoms, their gut health may be playing a role. Some signs to look out for include:
Frequent bloating, constipation or diarrhoea
Reflux or stomach pain with no clear cause
Food sensitivities or extreme picky eating
History of recurrent infections or frequent antibiotic use
Mood swings, anxiety or meltdowns after eating certain foods
Fatigue or brain fog
Tics, compulsions or increased hyperactivity
Improvements in behaviours after a bowel motion
If you notice these patterns, focusing on gut health may help improve both physical symptoms and behavioural challenges.
How to Support Your Child’s Gut-Brain Health
1. Identify and Reduce Gut Irritants
Certain foods and environmental factors can trigger inflammation and imbalance in the gut. These include:
Artificial additives and preservatives (found in processed snacks and drinks)
Refined sugar, which can fuel bad bacteria and yeast overgrowth
Gluten and dairy, which may contribute to gut permeability (leaky gut) in some children
Frequent antibiotic use which can disrupt microbiome balance
Intestinal worms can contribute to low iron and impact behaviours
By eliminating or reducing these irritants, many parents notice improvements in behaviour, focus and emotional stability.
2. Support a Healthy Microbiome with Whole Foods
Feeding the gut the right nutrients helps beneficial bacteria thrive. Focus on:
Fibre-rich fruits and vegetables (e.g., berries, leafy greens, sweet potatoes)
Fermented foods to introduce healthy probiotics (e.g., sauerkraut, kefir, plain yoghurt)
Healthy fats for brain support (e.g., avocado, olive oil, wild-caught fish)
Quality protein sources to stabilise blood sugar and mood (e.g., eggs, grass-fed meat, legumes)
3. Restore Gut Health with Probiotics and Prebiotics
Probiotics introduce beneficial bacteria that support gut and immune function.
Prebiotics (found in foods like garlic, onions and bananas) feed the good bacteria, helping them thrive.
For children with severe gut dysbiosis, targeted probiotics and functional gut testing can help identify specific imbalances.
4. Reduce Inflammation with Healing Nutrients
Certain nutrients help calm the immune system and repair the gut lining:
Zinc – Supports gut integrity and brain function
Omega-3 fatty acids – Reduce inflammation and support neurotransmitter production
Magnesium – Helps regulate mood, anxiety, and sleep
Glutamine – Repairs the gut lining and reduces leaky gut symptoms
How I Can Help
If your child struggles with PANS, PANDAS, Autism, ADHD, OCD, tics or anxiety, addressing gut health could be a game-changer. Through functional testing and personalised nutrition strategies, I help parents:
Identify gut imbalances affecting behaviour and mood
Create an easy-to-follow plan to restore digestive health
Support immune function and reduce neuroinflammation
Many families I work with see significant improvements in their child’s emotional regulation, focus and overall well-being once their gut health is addressed.
If you’re ready to explore how gut healing can support your child’s brain and behaviour, I invite you to book a free 20-minute discovery call.
