Anxious Mind, Unhappy Gut? The Gut-Mood Connection You Need to Know About
Have you ever felt sick to your stomach before a stressful event? Or noticed that anxiety throws off your digestion? You’re not imagining it—your gut and brain are deeply connected. Scientists now refer to this as the gut-brain axis, a two-way communication network linking your digestive system and central nervous system. And emerging research shows it plays a huge role in your mood, especially when it comes to stress and anxiety.
In this blog, we’ll break down the science behind the gut-brain axis, explore how your microbiome influences mental health, and share simple, evidence-based strategies to support a calmer gut and a more balanced mind.
What is the Gut-Brain Axis?
The gut-brain axis is the communication superhighway between the gastrointestinal tract and the brain, involving:
Neural pathways, especially the vagus nerve, which sends signals in both directions
Endocrine signalling, including hormones like cortisol and serotonin
Immune activation, including inflammatory cytokines
Microbial metabolites, such as short-chain fatty acids and tryptophan derivatives (1)
This complex system helps explain why emotional stress can cause digestive symptoms—and why gut imbalances can affect mental clarity, mood, and stress tolerance.
Your Gut Microbiome: More Than Just Digestion
Your gut hosts trillions of microorganisms—bacteria, fungi, viruses—collectively called the microbiome. While many people think of these microbes only in terms of digestion, they also:
Influence neurotransmitter production
Shape immune responses
Modulate inflammation
Affect brain function and behaviour (2)
When the balance of these microbes is disrupted (a state called dysbiosis), it can contribute to increased stress, lower resilience, and symptoms of anxiety or depression (3).
Neurotransmitters Made in the Gut
About 90% of serotonin—a key “feel good” neurotransmitter—is produced in the gut (4). Gut microbes also influence levels of:
GABA (gamma-aminobutyric acid), which helps calm the nervous system
Dopamine, involved in motivation and pleasure
Tryptophan, a precursor to serotonin, which gut bacteria help convert (5)
This means your gut environment can literally shape your emotional experience.
Gut Inflammation and the “Leaky Gut” Effect
Chronic stress can increase intestinal permeability, sometimes referred to as leaky gut. This allows bacterial components like lipopolysaccharides (LPS) to enter the bloodstream, triggering systemic inflammation—which has been associated with depressive and anxious states (6).
Once inflammation reaches the brain, it can disrupt neurotransmitter balance and even affect neuroplasticity—the brain’s ability to adapt and cope with stress (7).
The Role of the Vagus Nerve
The vagus nerve is like a superhighway connecting your gut to your brainstem. When stimulated by healthy gut microbes or calming practices like deep breathing, it sends “safety” signals to the brain, lowering heart rate, calming the nervous system, and reducing the stress response (8).
Interestingly, vagus nerve stimulation is being explored as a therapy for treatment-resistant depression and anxiety disorders.
How to Support the Gut-Brain Axis Through Nutrition
Here’s the good news: you can influence your gut-brain axis through what you eat, how you move, and how you manage stress.
1. Eat More Fibre
Soluble fibre (from oats, chia, legumes) feeds good gut bacteria
Results in production of short-chain fatty acids (SCFAs) that reduce gut inflammation and support brain health (9)
2. Include Fermented Foods
Yoghurt, kefir, miso, kimchi, and sauerkraut contain probiotics
Specific strains like Lactobacillus rhamnosus have been shown to reduce anxiety-like behaviour in animal models (10)
3. Limit Ultra-Processed Foods
High-sugar, high-fat processed diets promote dysbiosis
These foods also increase inflammation and disrupt neurotransmitter signalling (11)
4. Try Polyphenol-Rich Foods
Found in berries, green tea, olive oil, and dark chocolate
Act as prebiotics, feeding beneficial bacteria and reducing oxidative stress (12)
5. Stay Hydrated and Mind Alcohol
Dehydration affects digestion and microbial diversity
Alcohol can increase gut permeability and inflammation (13)
Supplements That May Help
Always speak with your healthcare provider before adding new supplements, but some evidence supports:
Probiotics: Especially strains like Lactobacillus helveticus and Bifidobacterium longum for mood support (14)
Omega-3s: Anti-inflammatory effects that may support brain and gut health (15)
Magnesium: Helps regulate the nervous system and may reduce anxiety symptoms (16)
L-glutamine: May support gut lining integrity in cases of increased permeability (17)
Lifestyle Strategies to Strengthen the Gut-Brain Axis
It’s not all about food. How you live affects your microbiome too.
Move regularly: Exercise increases microbial diversity (18)
Sleep well: Poor sleep harms both gut and brain health
Manage stress: Try breathing exercises, meditation, yoga, or nature walks—these also stimulate the vagus nerve
Reduce antibiotic overuse: These medications alter the gut microbiota long-term
When to Seek Help
If you struggle with digestive symptoms (like bloating, constipation, or IBS) and experience mood changes or anxiety, it might be time to look at the gut-brain axis more seriously. As a Clinical and Sports Nutritionist, I help clients uncover root causes and build tailored plans that support both mental and physical resilience.
Final Thoughts
The connection between your gut and brain is more than a trend—it’s a scientific reality. From neurotransmitters to inflammation and the food on your plate, your gut plays a critical role in how you feel, think, and cope with stress.
Small steps—like adding fibre, choosing fermented foods, and reducing processed meals—can add up to a calmer gut and a clearer, more stable mind.
References:
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Maes M, Kubera M, Leunis JC. The gut-brain barrier in major depression. Neuro Endocrinol Lett. 2008;29(1):117–24.
Kelly JR, et al. Breaking down the barriers: the gut microbiome, intestinal permeability and stress-related psychiatric disorders. Front Cell Neurosci. 2015;9:392.
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Bravo JA, Forsythe P, Chew MV, et al. Ingestion of Lactobacillus strain regulates emotional behaviour and central GABA receptor expression in a mouse via the vagus nerve. Proc Natl Acad Sci U S A. 2011;108(38):16050–5.
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Anhê FF, Nachbar RT, Varin TV, et al. Gut microbiota dysbiosis in obesity-linked metabolic diseases and prebiotic potential of polyphenol-rich foods. Curr Opin Biotechnol. 2020;61:121–6.
Engen PA, Green SJ, Voigt RM, et al. Alcohol effects on the composition of intestinal microbiota. Alcohol Res. 2015;37(2):223–36.
Messaoudi M, Lalonde R, Violle N, et al. Assessment of psychotropic-like properties of a probiotic formulation. Nutr Neurosci. 2011;14(4):209–15.
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