🧠 The Gut-Stress-Mental Wellbeing Connection 🧠
Mental wellbeing is not just a matter of the mind. The gut-brain axis is a powerful pathway that deeply connects gut health and brain health, influencing mental wellbeing, mood, cognition and stress. This bi-directional axis carries messages to and from the gut and brain allowing both systems to communicate.
Extensive evidence now shows that our gut microbiome is involved in much of the gut-brain axis communication. In fact, our microbiome is so important that researchers are increasingly coining it the microbiome-gut-brain axis. Through this microbiome-gut-brain axis connection, stress can have huge impacts on our gut, and gut health can affect our resilience to stress, as well as mood and mental state.
- How Stress Impacts Gut Health.
Persistent or excessive stress can impact the gut in an unpleasant way. Research has clearly shown that higher levels of stress hormones (such as norepinephrine, epinephrine, and cortisol) can bind to receptors in our gut and send signals that:
- Promote unfriendly bacteria and reduce healthy beneficial bacteria.
- Change the gut microbiome leading to dysbiosis and leaky gut (poor barrier permeability).
- Inhibit digestive secretions, reduce blood flow to the gut and reduce nutrient absorption.
- Affect gut motility, either causing less or more frequent visits to the bathroom.
- Induce intestinal inflammation and bloating.
Stress-related comfort eating can add to the problem. Researchers have found that high-sugar diets result in gut inflammation and dysbiosis due to changes in intestinal flora.
- How Gut Health Impacts Stress and Mental Wellbeing.
A healthy gut microbiome promotes better stress responses and mental wellbeing. This is especially relevant to women who are more likely to be affected by digestive issues, stress symptoms and mood disturbances.
Research suggests that women feel the symptoms of stress more and experience more of the symptoms of stress than men (due to hormonal biological differences). This has important implications as higher long-term stress levels in women are linked to poor mood, digestive symptoms, weight gain, low energy levels and hormonal complaints.
But how do our gut bacteria influence stress and mental wellbeing?
The intestinal bacteria making up our gut microbiome produce signalling molecules that traverse the microbiome-gut-brain axis from our digestive tract through the nervous system, vagus nerve, circulatory system, or immune system to the brain. Here they can affect mood, cognition, and behaviour.
- The microbiome produces neurotransmitters and hormones like serotonin, GABA (gamma-aminobutyric acid) and dopamine (our gut is home to 90% of our total serotonin). These regulate emotions, thoughts and mood – contributing to mental wellbeing.
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Microbiome imbalances can drive inflammation throughout the body and brain, disrupting neurotransmitter balance and stress hormones. When the gut bacteria balance is off, our intestinal barrier can become weak and inflammatory substances (such as lipopolysaccharides and cytokines) unwelcomely pass through our gut into the body where they can activate the HPA axis, increase cortisol and make stress symptoms worse.
- Beneficial gut bacteria metabolites modulate the stress response. Lactobacillus and Bifidobacterium have been shown to reduce cortisol levels and promote GABA, an inhibitory neurotransmitter that helps counteract stress. These friendly bacteria produce beneficial metabolites that influence brain function and mental wellbeing. When these bacteria feed on dietary fibre in our gut, they make short-chain fatty acids (SCFAs) like butyrate, acetate and propionate. These SCFAs maintain gut integrity, reduce inflammation and cross the blood-brain barrier where they help regulate mood and stress.
For centuries, wholistic medicine has believed that stress and mental wellness is deeply connected to the gut - that good health begins in the gut. Modern science now supports this connection with recent research unravelling the complex mechanisms that unite our gut, brain, stress and emotions.
About the Author | 📑
Hi, I’m Abbie – a naturopath, nutritionist, herbalist, wellness and nature lover.
Graduating from university almost 20 years ago, I have spent my career supporting brands to develop and market effective and compliant health products through my companies Regulatory Training Direct and Natural Product Centre.
Despite not working in clinical practice, naturopathic principles are a huge part of my life. Nutrition is an essential cornerstone to health, and I love cooking nourishing tasting meals that help my family look, feel and perform at our best.
I currently live in a small seaside town in Australia with my husband and beloved fur-baby. We spent years living abroad so my home cooking tends to be globally inspired intuitive fusions with a naturopathic twist.
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