Our gut in sensitive to our emotions, and our emotions can be impacted by the health of our gut. Have you ever had butterflies in your stomach, a gut feeling, or a gut-wrenching experience? The mind and the gut talk to each other, they are intricately linked. A healthy gut promotes a healthy stress response, and vice versa.


How does stress affect digestive function?


The gastrointestinal tract (GIT), is embedded with its own enteric nervous system, also known as the second brain. This complex neuronal network is responsible for regulating basic digestive functions, which enable us to breakdown and absorb nutrients from our food, move food through the GIT, and remove waste products and toxic material through the bowel. The brain bidirectionally communicates with the guts enteric nervous system via what’s known as the hypothalamic pituitary adrenal (HPA) axis, a major neuroendocrine system that controls the body’s reaction to stress.


Our autonomic nervous system regulates many bodily functions. It has two main divisions- sympathetic and parasympathetic. When we are faced with a stressful situation, our sympathetic nervous system becomes activated- this is our fight or flight response. During this time, we may experience pupil dilation, increased perspiration, increased heart rate and increased blood pressure. This is to prepare our body to either stay and fight the threat (stressful trigger), or get ready to run and flea the situation. Bodily processors that are not priority at this time, such as digestion, are temporarily inhibited.

When our body is relaxed, our parasympathetic nervous system is activated, and this is when we rest and digest optimally. For someone who is chronically stressed, and in constant sympathetically dominant state, gut function can be compromised, and symptoms can develop.


The major effects of stress on gut physiology include:

  1. Alterations in gut motility (diarrhoea or constipation)


  1. Increase in visceral perception- the way we feel sensations in our body (e.g. increased nausea, stomach ache, pain)


  1. Changes in gastrointestinal secretions (e.g. reduced stomach acid production leading to reduced breakdown of food, bloating, bacterial overgrowth, flatulence, constipation)


  1. Intestinal permeability (leaky gut), due to weakening of tight gap junctions that maintain intestinal integrity, allowing particles to enter circulation which can then trigger an immune response (e.g. food allergies and intolerances)


  1. Inflammation, reduced blood flow and reduced regenerative capacity of gut mucosa


Imbalances in gut function may also be associated with:

  • Acne
  • Eczema
  • Hormonal imbalances
  • Thrush and urinary tract infections
  • Weight problems
  • Fatigue
  • Autoimmune conditions


So how does our gut health effect our mood?


Serotonin is produced in the gut

95 per cent of the body’s feel good chemical serotonin, an important neurotransmitter that makes us feel happy and lifts our mood and cognition, is produced by beneficial bacteria that reside in our gut. Research is increasingly demonstrating that an imbalanced gut can cause an imbalance in serotonin production. This can lead to feelings of low mood, depression and anxiety.



Nutrient absorption


Serotonin production is crucially dependant on the availability of essential amino acids (building blocks of protein), along with cofactors such as zinc, magnesium and b group vitamins. If our diet is lacking in these vital nutrients, or if absorption is compromised due to poor gut function, we cannot produce and utilise these feel-good chemicals optimally. Our digestive secretions and gut microbiota play a vital role in regulating availability of these nutrients; therefore, we must make sure the digestive system is balanced and functioning optimally.


Bacterial imbalance and inflammation


If there is a bacterial imbalance in the gut, there will be inflammation present also. Inflammation in the gut disturbs intestinal barrier function, which means toxins and other particles can be absorbed through circulation and into the brain, and cross what is known as the blood-brain-barrier. This has detrimental consequences to our mood and cognition. You may experience symptoms such as:

  • Low mood, depression, anxiety
  • Foggy headedness
  • Headaches and migraines
  • Poor memory and difficulty concentrating


What can I do about this?

If you are someone experiencing any of these symptoms, healing and restoring proper function of the gut, ensuring adequate nutrient intake, and addressing stress management is key. Naturopathic medicine can help you!



Written by Sarah Hamilton

BHSc Naturopath

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