The gut - the source of good mental health?

The gut has capabilities beyond all our other organs, and even our brain. It has its own nervous system, and is sometimes referred to as the ‘second brain’.

The immune cells within the gut make up the largest component of the body’s immune system, and they are the first line of defence against toxins in our food & drink, and other potentially harmful microorganisms. The gut lining also contains the greatest concentration of endocrine cells, which hold hormones that can be released into the bloodstream at a moment’s notice. The gut is also the largest storage facility for serotonin in our body – 95% in fact. Serotonin helps push food through our digestive system, but is also critical for sleep, pain sensitivity, mood and overall feelings of wellbeing. Yet it is mostly located in our gut!

So, one of the roles of the gut (besides digesting our food) is to provide important signals to the brain, and in turn, the brain provides signals back to the gut. The gut is connected to the brain through thick nerve cables and transfers information in both directions via the bloodstream. Signals from the gut to the brain generate feelings such as fullness or nausea, or feelings of wellbeing, but the brain will also send signals back to the gut, generating ‘gut-reactions’.

These gut reactions are stored for later use, so what we sense in our gut will ultimately impact the decisions we make about what to eat, who we spend time with and how we make decisions. The information gathering cells in the gut listen in as the brain signals how stressed we are, how happy, how anxious, or angry. They then send signals back to the brain, reinforcing or prolonging that emotion.

We have always felt emotions in our gut. Think about common expressions such as — ‘my stomach was tied up in knots’, or ‘I had a gut-wrenching experience’, or ‘I had butterflies in my stomach’.

“The gut is like the theatre in which the drama of emotion plays out”. (The Mind-Gut Connection, Emeran Mayer MD)

These emotions can confuse even automatic functions such as digestion. If we are emotional while eating our dinner, the stomach’s digestive activity is switched off and instead goes into stressed out contractions that no longer allow emptying of the stomach. As you later go to bed, the partly digested meal prevents the digestive system doing its usual night time ‘sweep and cleanse’ of the digestive tract in preparation for the next morning. If food sits in our intestines for too long it can become toxic and produce further discomfort or illness.

When scientists study the guts of patients with anxiety disorders, depression or autism, they find changes in the gut cells which have adapted to these ‘high alert’ states. The same is true for those who have experienced stressful or painful childhoods – the body has been programmed and can produce exaggerated gut reactions. These gut reactions then send signals back to the brain to reinforce the high alert, even years after the threat or pain has passed.

In other words, the effect of long-term stress, chronic anger or fear can damage our guts, and likewise, long term poor diet can affect our gut health and ultimately, our emotional state. In fact 90% of the signals between brain and gut head up from the gut to the brain.

This means that the health of the gut can strongly influence our mental state.

To find out more about the gut and mental health, contact us for a FREE copy of Chapter 4: The Gut and Mental Health from our Living Well & Ageing Gracefully paperback, or purchase a full copy here