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  • Sarah Newland BHSc Nut Med

Is your GUT killing your HAPPINESS? Here's how the gut-brain-axis affects your feels.

Updated: Aug 11, 2020

The GBA is the bi-directional link between the CNS (central nervous system) & the ENS (enteric nervous system). It is a messenger system between the brains emotional and cognitive centres, and the digestive system.

Gut microbiota (aka ‘gut bacteria’, or the ‘microbiome’) are fundamental in GBA activity. Their significance is summarised in the following points:

  • The gut is full of microbes, which implicate all aspects of your health. At any given time there is about 2kg of microbes in your gut.

  • The microbiome behaves like an organ (or super organ!), and is at the epicentre of scientific research right now.

  • The genetic material in your microbiome is 150 x greater than your human genetic material (thus being termed ‘super-organism’)

  • Your gut microbiome is your second brain, and constitutes the ENS.

  • You actually contain more microbes than human cells! Sci-fi, right? And there is a lot of diversity – good and bad microbes exist in everyone.

  • Your gut microbiome can determine a lot about you – like your capacity to be lean or overweight

The bi-directional communications of the GBA involve the brains influence on intestinal function, and working in the other direction, your gastrointestinal tract and gut microbiota influence your brain activity, and mental health.

Your microbiome maturation starts during birth. Babies get an important coating of mums goop on their way out, during a natural birth. That goop is crucial to the development of their immune system, gut microbiome, and nervous system.

As you grow up, your diet, antibiotics taken, your environment, any other medications, lack of veggies, lack of essential fats and healthy proteins, too many processed foods, refined carbohydrates and grains, bad oils and sugars… all impact your microbiome and the bi directional channels between your gut and nervous system.

It makes sense and is generally accepted that these influences will impact how your digestive tract operates. Motility, digestion, nutrient absorption, and the development of food intolerances are all implicated.

But in addition to the gastrointestinal implications, these diet and lifestyle factors also have a direct and significant influence on your capacity for sound mental health.

The mechanisms by which gut microbes affect mental health include:

  • Sleep quality

  • Mood regulation

  • Capacity to control emotional responses

  • Anxiety

  • Depression

  • ADHD

  • Autism spectrum disorders

  • Cognitive decline

So much of your physical and emotional wellbeing is affected by the gut-brain signalling system. 90-95% of your serotonin is produced by your gut mucosa. 70% of your immune cells are produced in the gut. Many neuro-active substances and hormones are produced by gut cells. And almost all of your nutrient absorption and assimilation around the body depends on healthy gut function. So when your gut is in poor health or needs healing, your immune system, mood, anxiety, hormones, and nutritional profile can all be affected.

But how exactly?

Because, gut microbes interact with the gut brain axis (and as such your mental health) in the following ways:

1. The vagus nerve – a very important cranial nerve, is literally the ENS highway between your gut and brain. It’s the key component of your parasympathetic nervous system. It’s crucial to stress responses, heart rate, and immune responses. Science now shows the vagus nerve is stimulated by microbes from the gut, which directly affect mood and anxiety. Translation: gut microbes have direct communications with brain tissues via vagus channels.

2. Neuro-endocrine signalling (translation: communications between gut hormones and your brain). This can be hunger hormones, metabolic hormones, or stress hormones.

3. 90 - 95% 5-HT (serotonin) is produced by gut mucosal cells. Not only is serotonin involved in happiness, but gut muscle contract/relaxation. Gut microbes affect the mucosal cells ability to produce the serotonin. And, gut microbes produce other Neuroactive substances too.

4. Mental health and immune system links. Antibiotics destroy both good and bad gut microbes, and unfortunately are not ‘strain specific’ when killing bacteria. 70% of your immune cells produced in your gut, thus poor immune cell production affects GBA communications.

5. Chronic stress! High levels of circulating cortisol causes inflammation of the gut and disturbs microflora. Chronic stress induced inflammation also leads to intestinal permeability (IP), which is linked to depression & psychiatric disorders. IP can also implicate circulating endotoxins, which can affect neurological health.

The take home message is essentially that a poor diet and lifestyle affects your gut microbiome significantly, which is directly related to mental health and nervous system symptoms.

There is a lot of evidence of dysbiosis in the gut causing functional GI disorders like IBD. Most health professionals nowadays agree that microbiome disturbances are part of the cause or continuance of intestinal disease or symptoms.

And, working in reverse, the CNS response to psychological, emotional, and physical stress can cause gut microbe imbalances, and result in IBS and/or IBD.

This again highlights the bi-directional nature of the GBA.

So, how do you heal your gut and improve mental health using nutrition?

It can be a journey. When you think about the diversity of the microbiome, 150 x greater genetic material than human genetic material (!!!)… it makes sense that everyone’s gut picture is VERY different and can involve a different healing path.

These are our 5 essential steps I use to help my clients heal their gut.

FIRSTLY – and obviously – remove the gut killers.

Gluten, processed foods, sugars, refined carbs, baked goods, bad oils etc.

No amount of healing protocols can replace the importance of removing the stuff that does the damage in the first place!

With that understood, then use these 5 strategies.

1. Heal the mucosal gut lining – bone broth is my number one for this. Depending on the nature and severity of the damage, this might involve taking out a significant amount of foods from their diet for a period of time to allow the bone broth nutrition to work its magic uninterrupted. BB has bioavailable collagen, gelatin, and healing amino acids proline, glycine, glutamine and arginine.

2. Reduce pathogenic populations. This means starving and killing off the bad guys; depriving the pathogenic bacterial populations of the diet they need to thrive. And importantly, removing the sugars that feed the bad guys!

3. Then, re-populating the gut with good bacteria. Probiotic foods like kefir, natural yoghurt, fermented veggies like sauerkraut are all ‘go-to’ foods for this, along with high dose probiotic supplements. Maintain concurrent use of healing bone broth, and include coconut oil, avocados and omega 3 rich foods like wild salmon in your diet.

4. Ensuring a prebiotic rich diet to feed the new good bacteria, and help them populate. Prebiotic rich veggies like asparagus and Jerusalem artichokes concurrently provide gentle fibre to help gut motility and carrying out the debris.

5. Mindfulness and stress management. Sadly, none of this has its best chance of working when the sympathetic nervous system is activated and you have inflammatory levels of cortisol flowing through your system. Slow breathing exercises and ‘rest and digest mode’ is essential for these protocols to work well!

Making gut healing bone broth and probiotic foods a diet and lifestyle staple will give your gut the long term loving it needs. This will continue to deliver collagen and bioactive nutrition. We love having bone broth in the morning and at night, and having sauerkraut, kimchi, properly fermented kombucha, kefir, natural unsweetened yoghurt, organic miso as regular features in your daily diet J

For one on one guidance with a 30-60 day tailored program to get your gut healing on it’s way, please contact us at and we can fill you in on prices and details.

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