If you've ever felt butterflies before a nerve-wracking moment, lost your appetite under stress, or noticed your digestion seems worse during anxious periods — you've already experienced the gut–brain axis in action. This relationship between your gut and your brain is one of the most fascinating and clinically relevant areas of research in modern medicine, and it's central to how we approach health from a naturopathic perspective.

Here's what's actually happening, and why it matters for so much more than just digestion.

What is the Gut–Brain Axis?

The gut–brain axis is a two-way communication system between your digestive system and your brain. Rather than signals travelling in one direction, this is a constant, bidirectional conversation — your gut influencing your brain, and your brain influencing your gut.

This communication happens through multiple pathways:

• The vagus nerve — the body's primary communication highway between gut and brain

• The immune system — your gut houses approximately 70–80% of your immune tissue

• Hormones — including cortisol, which is directly influenced by gut health

• Your gut microbiome — the trillions of bacteria, fungi, and microorganisms living in your digestive tract

Your gut doesn't just digest food. It is constantly sending signals that influence your mood, cognition, stress response, nervous system, and sleep — and all of these are deeply shaped by what you eat, and how you eat it.

Serotonin, Neurotransmitters & Your Gut

Here's something that surprises almost everyone: approximately 90% of your body's serotonin is produced in the gut — not the brain.

Serotonin is a key neurotransmitter that helps regulate both gut function (including motility — how well food moves through your digestive system) and brain-related processes including mood, sleep, and stress response. It acts as a critical messenger between the gut and the nervous system.

Beyond serotonin, your gut microbiome also plays a significant role in regulating other neurotransmitters, including dopamine and GABA. These influence:
→ Mood and anxiety levels
→ Stress resilience
→ Sleep quality
→ Gut motility and digestive comfort

What this means in practice: the state of your gut has a direct impact on how you feel, think, and cope emotionally. And equally, your mental and emotional state can influence how your digestion functions. It goes both ways.

Signs Your Gut–Brain Axis May Be Out of Balance

The gut–brain connection shows up in a wide range of symptoms that might not seem obviously related at first. You might notice:

• Anxiety, low mood, or depression that occurs alongside digestive symptoms

• Bloating, IBS, or IBD — particularly symptoms that worsen under stress

• Brain fog or difficulty concentrating

• Persistent fatigue or disrupted sleep

• Food sensitivities that flare during stressful periods

• Hormonal imbalances, including PCOS and endometriosis

• Skin conditions such as acne or eczema

• Signs of chronic inflammation or autoimmune presentations

For many people, this becomes a self-reinforcing cycle: stress worsens gut symptoms, and gut symptoms create more stress on the body.

How to Support Your Gut–Brain Axis

The good news is that the gut–brain axis is highly responsive to what we do every day. Small, consistent changes in how you eat, move, and manage stress can make a meaningful difference to both your digestive health and your mental wellbeing. Here's where to start.

1 : Fibre Intake

Aim for around 30 different plant foods per week, and approximately 10 grams of fibre per meal — alongside adequate hydration.
Foods to focus on: fruits, vegetables, whole grains, legumes, nuts and seeds.
→ Fuels beneficial gut bacteria
→ Stimulates production of short-chain fatty acids, which reduce inflammation and support the integrity of the gut lining
→ Improves stool consistency and regularity

2 : Polyphenol-Rich Foods

Polyphenols are plant compounds with powerful antioxidant and anti-inflammatory properties — they act like a prebiotic, selectively feeding beneficial microbes in your gut. Foods rich in polyphenols: berries, extra virgin olive oil, cacao, dark leafy greens, pomegranate, and green tea.
→ Support microbiome diversity
→ Reduce inflammatory signalling in the gut
→ Antioxidant and anti-inflammatory effects throughout the body

3 : Fermented Foods

Aim to include at least one serve of fermented food daily. Options include kefir, kimchi, sauerkraut, miso, and tempeh.
→ Support microbial diversity
→ Reduce inflammatory signalling
→ Provide beneficial bacteria that support both gut and brain health

4 : Protein intake

Aim for 20–30 grams of protein per meal. Good sources include eggs, meat, poultry, tofu, legumes, nuts, and seeds.
Protein provides essential amino acids — including tryptophan, tyrosine, and glutamine — which are the direct building blocks for neurotransmitter production, including serotonin and dopamine.
→ Supports neurotransmitter production
→ Regulates energy, mood, and sleep
→ Supports nervous system function and stress resilience

5 : Vagus nerve & lifestyle support

The vagus nerve is the primary communication line between your gut and brain, we can actively support its function through daily habits.

→ Practice diaphragmatic or box breathing, especially before meals as this activates the parasympathetic nervous system and primes your gut for digestion
→ Eat in a calm, relaxed state where possible; the cephalic phase of digestion (triggered by sight, smell, and anticipation of food) is an important and often overlooked step
→ Prioritise sleep — your gut microbiome follows a circadian rhythm and is deeply affected by poor sleep
→ Move daily to support gut motility and vagal tone
→ Reduce ultra-processed foods, which deplete microbial diversity and increase gut inflammation

Your gut influences far more than digestion. It plays a central role in your mood, stress response, hormonal health, immune function, and mental clarity. When we support the gut, we support the brain — and vice versa.

In clinic, I rarely treat these systems in isolation, because the evidence simply doesn't support viewing them as separate. Whether you're dealing with IBS, anxiety, hormonal imbalance, skin concerns, or fatigue, the gut–brain axis is almost always part of the conversation.

If this resonates with what you've been experiencing, I'd love to help you understand what could be driving your symptoms, and support you in reclaiming your health.