the gut-brain axis and mental health

Written By Sarah Duke

Did you know?

Around 90–95% of your body’s serotonin is produced in your gut.

Serotonin is a key chemical involved in mood, sleep, appetite, and stress response. While brain serotonin is critical for mental health, most of the body’s serotonin is actually made in the intestines by specialised gut cells and is strongly influenced by your gut microbes.

This is a core part of the gut–brain axis , which is a two‑way communication network between your digestive system and your brain.

The gut–brain axis and mental health

Your gut and brain are in constant conversation via:

  • The vagus nerve

  • Immune and inflammatory signals

  • Hormones and neurotransmitters (including serotonin, GABA, dopamine)

  • Microbial metabolites such as short‑chain fatty acids (SCFAs)

When the gut microbiome is balanced and diverse, this communication tends to support:

  • Stable mood and emotional resilience

  • Better sleep and energy

  • Healthier stress responses

  • More balanced hormones

When the gut environment is compromised (dysbiosis, inflammation, “leaky gut”), research shows associations with:

  • Increased risk of anxiety and depression

  • Mood swings, irritability, and low motivation

  • Fatigue, brain fog, and sleep disturbance

  • Hormonal imbalances (e.g. PMS, perimenopausal mood changes)

Studies consistently find that people with anxiety and depression may have:

  • Lower microbial diversity

  • Fewer beneficial, SCFA‑producing bacteria (e.g. Faecalibacterium, Lactobacillus, Bifidobacterium)

  • More pro‑inflammatory species

Interventions that support the microbiome such as targeted diet, pre/probiotics, and lifestyle changes are showing promise in reducing symptoms of anxiety and depression, especially when combined with standard care.

That’s why supporting a healthy gut environment is so important for mental health.

A resilient, diverse microbiome helps create the biochemical conditions your brain needs to feel calm, focused, and emotionally steady.

How a naturopath can help

As a naturopath, I work with you to rebuild your gut terrain and support the gut-brain axis, alongside any medical or psychological care you’re receiving.

Areas of focus:

  • Gut-brain axis to improve mental health

  • Nervous system nourishment through diet

  • Liver detoxification and protection

  • Digestive symptoms (bloating, reflux, IBS, alternating bowel movements) that often travel with mood concerns

What’s included in your tailored treatment plan?

1. Comprehensive assessment

  • Detailed health history (mental health, gut, diet, sleep, stress, medications)

  • Review of any existing pathology and symptoms

  • Identification of likely patterns: dysbiosis, inflammation, nutrient gaps, digestive weakness

2. Personalised food plan

  • Foods to enjoy to nourish your microbiome and neurotransmitters

  • Foods to limit or avoid if they aggravate inflammation, blood sugar swings, or gut symptoms

  • Simple, realistic sample meal plan aligned with your lifestyle, culture, and budget

3. Targeted nutraceuticals and herbs

  • Evidence‑informed use of:

    • Probiotics

    • Prebiotic fibres and fermented foods

    • Gut‑soothing and barrier‑supportive herbs and nutrients

    • Nervous system-nourishing botanicals (e.g. adaptogens, calming herbs)

  • Coordinated with your GP/psychologist/therapist as needed. Safety is my first priority.

4. Lifestyle & nervous system support

  • Sleep hygiene strategies

  • Stress‑regulation tools (breathwork, movement, mindfulness)

  • Gentle, sustainable routines to support both gut and brain

Ready to support your mental health from the gut up?

If you’re experiencing low mood, anxiety, brain fog, poor sleep, or hormonal changes and suspect your gut might be part of the picture, a naturopathic approach can help you build a stronger foundation for mental wellbeing.

Book a consultation to create a tailored plan for your gut, brain, and overall health.

This information is educational and not a substitute for medical advice, diagnosis or treatment.

REFERENCES
Novel aspects of enteric serotonergic signaling in health and brain-gut disease - PMC
The gut–brain connection: microbes’ influence on mental health and psychological disorders - PMC
Gut Microbiota and Mental Health: A Comprehensive Review of Gut-Brain Interactions in Mood Disorders - PMC
Understanding the Impact of the Gut Microbiome on Mental Health: A Systematic Review - PubMed
Efficacy of Gut Microbiome-Targeted Interventions on Mental Health Symptoms in Women Across Key Hormonal Life Stages: A Systematic Review and Meta-Analysis of Randomized Controlled Trials - PMC

Sarah Duke
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