Gut and Mood Connection – The Vagus Nerve

As far back as the 1960’s the term “gut-brain axis” was coined, based on the understanding that the brain controlled gut function. This was due to neuropeptides (a protein neuron’s use to communicate with each other) found in the gut also being discovered in the brain.[i] It wasn’t until more recently; further research gave a more complete picture, i.e. it is a bidirectional communication system between the central nervous system and the gastrointestinal tract via the vagus nerve.[ii] That basically means that equally the condition of our digestive health directly affects our mental health & can be as serious as causing a significant chemical imbalance.

This is not really surprising if we consider that 90% of the body’s serotonin and 50% of its dopamine are synthesized in the gut and regulated by the gut flora[iii].

Food Intolerance Inflammation & Mental Health

So that’s why there is so much hype and excitement about probiotics (provides healthy bacteria) & how important they are for mood and digestion. When there is dysbiosis i.e. imbalance of microbes, there is flatulence, acid reflux, constipation, diarrhea, fungal infections, bloating, skin outbreaks and sudden bouts of tiredness. If this is ignored the next stage is autoimmune type conditions such as chronic pain and inflammation.

Interestingly different good bacteria perform different functions in the human body as they are organised and need to keep their host healthy, such as mopping up toxins from infection & preventing overgrowth of yeast or facilitating conversion of dopamine & serotonin. Current research being carried out in the area of ‘designer probiotics’ to target specific diseases. An example of this would be psychobiotics, probiotics shown to alleviate symptoms of depression or anxiety and include lactobacillus helveticus, lactobacillus rhamnosus, bifidobacterium breve and longum.[iv] This list is by no means complete.

What’s Happening in Ireland?

The Republic of Ireland has one of the highest suicide rates in Europe among teens according to a 2014 article in the Irish Examiner[v] and one in 5 adults in Northern Ireland has mental health illness[vi]. According to the Ireland Coeliac Society there are currently 46,000 people diagnosed with coeliac disease in Ireland making it one of the highest percentages in the world. [vii].

We owe it to ourselves to explore this connection between food intolerances, inflammatory conditions and mental health.

Food Intolerances

Certainly no one eats a piece of bread one day and wakes up depressed the next and these are the sort of silly come backs that may be thrown around by cynics who have built their careers on a more conservative understanding of mental health or by those who find it too hard to give up the foods they love. Gluten is made up of 2 proteins gliadin & glutanin which forms a thick glue like substance when combined in the baking process. Any continued stress in the body or low enzyme availability due to poor diet or existing medical conditions will make it very hard to for the body to break down such a substance & an intolerance begins to develop.

Food Intolerances

Food intolerance’s cause inflammation and a slow degradation of the delicate villi in the colon wall that interferes with food absorption and production of important neurotransmitters such as serotonin and dopamine. Conventional treatment for mental health often prescribes medication to influence these two important brain chemicals when in a significant amount of cases wellness can be achieved through diet, herbs and wholefood supplementation. Authors such as Kelly Brogan author of A Mind of Your Own, Dr. Natasha Campbell Author of Gut and Psychology syndrome and neurologist David Perlmutter, author of New York Times Bestseller Grain Brain, are all receiving a lot of attention and support in this moment due to their success in treating autism, auto immune conditions and mental illness using predominantly a drug free approach. I recommend anyone of them to keep yourself informed. An estimated one-fifth of the population of the UK believe that they have adverse reactions to food[viii]. The classic trigger foods are Lactose, Gluten, Yeast and Sugar (including alcohol).

Food Intolerances

Inflammation is the body’s immune system’s response to infection and injury and is at the heart of many diseases in the body including arthritis, cancer, neuro degenerative and cardiovascular disease[ix]. People with autoimmune disorders nearly always have chronic digestive disturbances.

In my experience poor bowel habits and digestive disorders are largely ignored or normalised.

Inflammation may not always manifest as a significant digestive disturbance, other common symptoms are itching, eczema, asthma, sinusitis, hay fever and chronic tiredness. When a gut has some defect due to stress, poor lifestyle and diet or low digestive enzymes due to an existing condition consuming trigger foods can cause food to lay undigested. It eventually ferments and causes an overgrowth of bacteria(dysbiosis) and causing damage to the gut wall. Prostaglandins are made at sites of tissue damage or infection, where they cause inflammation, pain and fever as part of the healing process[x]. Where the skin is involved taking steroids is a common affair. Inflammation can be seed as a call to action and taking anti inflammatories as a single solution is a mistake for long term health. The immune system now becomes compromised causing low immunity or hyper immunity. The former leading to frequent colds and flu’s and the latter to auto immune type conditions. This owes to the fact, 70% of our immune system is in the mucosal lining of the gut. The pathology then goes deeper and the body may reject more food types that previously were not a problem.


Any symptoms such as itching, tiredness, bloating, constipation/diarrhoea, reflux, respiratory problems etc should never go untreated as they potentially can affect mood and mental health in the long term or go deeper. Children are the easiest to treat as they still have a relatively clean system and their bodies are efficient at repair and recovery.

Minding the gut brain begins with expectant mothers and they should be supported to ensure they are looking after their gut health. The first gift a mother gives to the child is her immunity via placenta, through a natural birth and her milk supply. Every pregnancy should include a probiotic supplement or regular fermented foods although care needs to be taken with dosage in the beginning just to avoid abdominal discomfort.

Below is a general protocol I use.

  1. Remove the trigger foods for a period of time,
  2. Take herbal anti inflammatories or adrenal tonics (depending on present medication) and symptom picture
  3. Improve bowel movement
  4. Take probiotics or fermented foods
  5. Choose one mind body technique to deal with stress
  6. Variable personalised add ons, including short term supplementation such as the B vitamins and Essential Fatty Acids (EFA’s), depending on the nature of the illness as each cocktail of nutrients provide different end results.

Patients in the clinic benefit greatly from this approach and see a marked improvement in pain, mood and energy levels in a relatively short period of time.

[i] PubMed, Neuropeptides and the Microbiota-Gut-Brain Axis, Holzer P., Farzi A. Published 15 mar 2015 Available online : (accessed 10 April 2018)

[ii] From gut dysbiosis to altered brain function and mental illness: mechanisms and pathways G B Rogers,1,* D J Keating,2 R L Young,3 M-L Wong,4 J Licinio,4 and S Wesselingh1 April 2016

[iii] The Gut, The Brain and Addiction. Sat Daram Kaur Pub Sep 2016. Available online at: (accessed 10 June 2018)


[v] Irish teen suicide rates among highest in EU Sheehan. C. ; Available online at: (accessed 21 Mar 2014.)


[vii] Coeliac Society Ireland. Prevalence and Diagnosis; (Online: Accessed 13 May 2018)

[viii] The diagnosis and management of food allergy and food intolerances J. L. Turnbull, H. N. Adams & D. A. Gorard Published online 14 Oct 2014. Available at : (accessed 12 April 2018)



Siobhan Shinnors

Siobhan Shinnors

Herbalist, Nutritionist, Iridologist and Yoga Therapy

Siobhan Shinnors

Siobhan Shinnors

Herbalist, Nutritionist, Iridologist and Yoga Therapy

Leave a Reply

Your email address will not be published. Required fields are marked *