What you think, feel, see and believe dramatically impacts the state of your physical health.

The gut brain connection is an amazing circular system in our body that is the internal joining point from mental to physical and back again.

This system is intricate and clever, quietly working to keep our internal systems in balance while being constantly bombarded by external factors that threaten stability and health.

When this system is working well our body and health is resilient, inflammation stays under control, we feel good and our mental game is strong.

When it gets out of balance the flow-on effects can be felt throughout the body as pain, inflammation, fatigue, fogginess and just generally feeling like age is catching up too fast.


To really understand this process it can be helpful to follow the cycle from brain to gut and back again and understand the processes and implications at each step of the way.

The brain, being the control center of the body, communicates with all systems and parts of the body through the release of hormones and neurotransmitters.

Hormones like serotonin, GABA and melatonin can have positive effects on our health, improving sleep, relaxation, feelings of wellbeing and reducing inflammation.

Hormones like adrenaline and cortisol, while part of our body’s safety systems, can have negative effects when they are released in a chronic or ongoing way.

In the face of a stressor, whether it’s significant or minor, our brain releases a dual pronged stress hormone cascade.


The fast acting stress hormones, adrenaline and norepinephrine are released first and these have been shown to produce an array of negative effects on the bacterial population in our gut. 

In the research it’s been shown that these hormones decrease good bacteria levels and promote the growth of the less beneficial strains of microbes that are present in our gut.

Our gut microbiome is a collection of the good, the bad and the ugly and on balance this diversity is the hallmark of a resilient gut. Issues arise when the not so great strains increase in ratio, over-taking the good guys.

It’s not so much an infection as it is an imbalance.

The fast acting stress hormones promote this imbalance and increase the resilience of the bad guys making them harder to kill and bring back to appropriate levels.

This change in diversity can lead to lower levels of hormones and neurotransmitters, reduced production of gut based anti-inflammatory molecules and increased production of bacterial toxic by products which negatively impact brain health.


The slower acting stress hormone response is more about cortisol. Cortisol has been shown to have multiple effects on gut function. Primarily in relation to physical and chemical function.

In states of chronically elevated cortisol there is increased intestinal permeability, which is sometimes referred to as leaky gut. The cells that make up our digestive tract and separate the contents of our intestines from the bloodstream starts to open up, allowing food particles, bacteria, chemicals and toxins through into our body.

These particles come in contact with our circulating immune cells at this point and a systemic immune response is triggered. This leads to the release of inflammatory chemicals which creates inflammation that can show up and present at many places throughout the body.

Throughout the lining of our now leaky digestive system, there are millions of nerve endings. In fact it’s suggested that there are more nerve endings lining our digestive system than through our whole spinal cord.

These nerves start to be triggered by the changing environment and can increase the perception of visceral pain and discomfort in the abdomen.


So we have a change in diversity from the fasting acting stress hormones and change in physical function impacting immune response and pain from the slower acting stress response.

All this activity sends messages back to the brain, alerting it to the fact that all is not well. Because the brain’s job is to keep our body in balance and keep us safe, it responds by further increasing the stress and immune response in a bid to fight what it deems as a threat.


In the short term, this gut-brain communication is a positive adaptive experience. It’s kind of like getting a scare when you are learning to drive and realizing just how careful you need to be. The near miss can ultimately make you a better driver in the long run.

When this loop is activated in the short term, our brain, our gut and our immune system all become more resilient. They learn what to react to and what not to react to and how to better restore balance after the fact.

The trouble is, many of us live in a state of constant mild stress stimulation. We are rushed and under-slept, overreacting and eating badly. Our actions and lifestyles are constantly giving our brain the signal to react, so our gut is under a constant barrage of chronic stress hormones.

What was positive and adaptive in the short term becomes destructive to our health in the long term.

  • Inflammation increases resulting in painful joints, upset digestive system and inflamed skin.
  • Blood sugar increases due to cortisol which can lead to type 2 diabetes, high blood pressure and increased cardiovascular risk.
  • Brain signaling is disrupted leading to mental health issues like depression and anxiety
  • Nutrients are rapidly depleted due to our body fighting a silent battle, so things don’t repair as well


The beauty of this system really lies in the fact that while disruption can occur at any point in the system, we can also intervene at any point of the system to help restore balance and bring things back to optimal.


Being prescriptive with daily practices that allow our nervous system to come out of fight/flight mode and settle back into rest/digest mode is key because it’s getting right to the root of the issues.

We often talk about mindfulness and meditation but so few people that I talk to have actually taken the time to instill these practices in their day.

Habits like box breathing, guided meditations, daily walks in the sun and fresh air, connecting with family and friends, participating in activities that bring joy and fulfillment. These are all things that can bring your nervous system back down and reduce that barrage of stress hormones to the gut.

The key is, it doesn’t work if we just think it’s a nice idea. It works when we take action and actually make these a routine part of our life.

The research in this area is growing rapidly at the moment but the changes in stress hormone levels can be measured and seen to have significant changes both positively and negatively with small inputs. So the takeaway here is that even a 10 minute walk per day is a worthwhile investment in your long term health.


There is research that has looked at the impact of probiotics in mental health outcomes and we see improvement in symptoms of depression and anxiety when these are added in.

This shows just how much what we put in our body can have dramatic effects on how we think and feel. 

We can support our gut brain connection through things like vegetable diversity, adequate protein, fermented foods, probiotics and fibre.

These things increase our microbial diversity and build resilience in the gut and gut lining to withstand and recover post the inevitable stress that will come.


The gut brain connection is a brilliant example of just how interconnected everything in our body is and how everything we do is either building or pulling apart our long term health, energy and longevity.

When we approach health from the angle of nutrition, mindset, movement and lifestyle design we create compounding positive benefits to our internal systems. These effects ripple out through our life and health, resulting in a body that no longer holds you back.

If you have feel your body responding differently and want help to reset your gut health and daily habits for better energy, body shape and health markers, learn more about Body Reset coaching here: https://bodyreset.online/personal-health-coaching-over-40/

Written by Mandy Harris (Body Reset Clinical Nutritionist)