Triggered: Your Gut under Stress

The Stress-Gut Feedback Loop

Whether it’s emotional stress, poor sleep, overtraining, or undernourishment, different stressors activate your body’s fight-or-flight response, releasing stress hormones like adrenaline, noradrenaline, and dopamine. These biochemicals don’t just stay in your bloodstream they influence your gut environment.

Here’s what happens when stress lingers:

• Gut barrier function weakens, increasing permeability (“leaky gut”)
• Inflammatory markers rise, fueling systemic dysfunction
• Gut motility becomes irregular, hello bloating, cramping, or constipation
• Digestive enzymes, stomach acid, and nutrient absorption decline
• Microbial balance shifts, favouring the growth of pathogenic strains

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Even more concerning? These stress hormones have been shown to encourage the virulence of bacteria like E.coli, H. pylori, Klebsiella, and Clostridium, which can further compromise your gut and immune system.

Your Microbiome Feels It Too

Your gut is more than digestion, t’s your second brain. Beneficial microbes like Lactobacillus and Bifidobacterium help produce Gaba, a calming neurotransmitter that plays a key role in reducing anxiety, improving sleep, and regulating pain perception.

Low microbial diversity or low fibre intake can impair this production, leaving you more prone to mood swings, irritability, and fatigue (2).

In fact, several strains of bacteria in your gut are directly involved in neurotransmitter synthesis, including:

• GABA - calming and sleep-promoting
• Serotonin - mood stabilising
• Dopamine - motivation, alertness, reward response
• Noradrenaline - stress, vigilance, and heart rate regulation

So, when stress disrupts your gut, your brain chemistry feels it too.

What Testing Can Reveal

A GI-MAP or functional stool analysis can provide clinical insight into:

• Presence of stress-hormone responsive pathogens (e.g. Klebsiella, Pseudomonas)
• Markers of intestinal inflammation (calprotectin, eosinophils)
• Secretory IgA (immune function and barrier protection)
• Diversity of beneficial bacteria linked to neurotransmitter health
• Signs of leaky gut or impaired digestion

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This data helps connect the dots between your symptoms and underlying gut dysfunction, especially in complex cases involving stress, fatigue, anxiety, or insomnia.

Evidence-Based Lifestyle & Nutrition Interventions

Supporting the microbiome through nutrition and nervous system regulation is foundational. Focus on:

Nutrition:

• Fibre-rich, plant-forward meals to feed beneficial microbes
• Fermented foods: kefir, kimchi, sauerkraut, miso
• Polyphenol-rich produce: berries, olive oil, herbs, dark greens
• Omega-3 fats: salmon, flax, walnuts to reduce inflammation
• Pre- and probiotics: targeted support based on testing
• Time-restricted eating: to support gut repair and circadian rhythms

Lifestyle:

• Mindfulness & breath work to down regulate stress
• Moderate, consistent movement such as walking, pilates and yoga
• CBT or gut-directed hypnotherapy for stress-related GI symptoms
• Sleep hygiene critical for microbiome and hormone reset

The Bottom Line

If you’re constantly running on adrenaline, feeling mentally foggy, or stuck in a loop of stress and digestive issues, your gut may be signalling for support.

The stress-microbiome connection isn’t just a theory it’s a physiological feedback loop affecting everything from your mood to your metabolism.

And the good news? It’s modifiable.

With the right testing, nutrition, and nervous system strategies, you can reset this loop and reclaim your calm, clarity, and gut health from the inside out.

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References

(1). Designs for Health. (2024). Stress and the Microbiome.

(2). Hamamah, S., et al. (2022). Role of microbiota-gut-brain axis in regulating dopaminergic signalling. Biomedicines, 10(2), 436.

‍https://www.mdpi.com/2227-9059/10/2/436

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