The Gut and Brain Connection

What is the gut and brain connection? Also called the “gut-brain axis”, it is the two-way nervous and chemical link between your gut and your brain. This connection works both ways, so disturbance in your gut can affect your brain and vice versa. Researchers have found that there is a complete nervous system running along the entire length of your gastro-intestinal canal, called the enteric nervous system or “second brain”. 

There are two ways the gut and brain communicate with each other:

  • Physically through the vagus nerve which controls messages between the brain and gut as well as other vital organs.
  • Chemically through neurotransmitters and hormones that send messages.

The gut microbiome connection

In other discusions we have described the gut microbiome which consists of billions of bacteria, fungi and virusses that form a balanced ecology in a healthy person. These organisms can promote health, be harmless or harmful. When an overgrowth of harmful organisms occur the result is an imbalance called dysbiosis which can lead to a multitude of physical and mental problems.

It stands to reason that an unbalanced gut microbiome is intricately linked to disturbances in the chemical and hormonal functioning of your gut directly, affecting the messaging between your gut and brain. Neurotransmitters are chemicals that carry signals between the gut and the brain. One example is serotonin, the “feel good” neurotransmitter which is mostly produced in the gut, and most of it by gut bacteria.

Gut microbes also produce short chain fatty acids (SCFA) such as butyrate, propionate and acetate by digesting fiber. SCFA influences brain functioning in a variety of ways. Propionate for instance can keep your appetite in check by reducing the activity in the brain related to reward from high-energy food. 

Butyrate and the microbes that produce it play an important role in forming the barrier between the brain and the blood, also called the blood-brain barrier. Bile acids (chemicals produced by the liver) and amino acids are also metabolized by gut bacteria and affect the brain. 

Gut health and mental health are linked

So there is a relationship between experiencing mental problems and digestive problems. The stress response, also called the “fight or flight response”, leads to a huge number of physical and mental effects that are actually designed to assist you through the stress situation, as long as it passes in a reasonable period of time. The problem with modern life is that stress and anxiety is often an ongoing condition, and the stress response actually makes us sick after a while. We can turn on the stress response by worrying unnecessarily, ruminating on negative issues too much and feeling anxious all the time.

For many people like myself the effects of stress and anxiety are mostly felt in the gut. It can becomes a vicious cycle; anxiety leading to gut problems and pain, leading to more anxiety and so on. 

Similarly an unhealthy diet, drinking too much, lack of exercise and medicines like antibiotics can disturb the gut microbiome balance, leading to stress, depression and anxiety. Even if you suffer from pre-existing mental conditions, that disturbance can make it worse.

An unhealthy lifestyle can trigger your immune system for long periods which can lead to inflammation, which in turn has been associated with mental disorders like depression, dementia and schizophrenia. Lipopolysaccharide (LPS), an inflammatory toxin made by certain bacteria can cause inflammation if too much of it passes from the gut into the blood. A balanced gut microbiome helps to regulate your immune system and inflammation by controlling what is absorbed by the body and what is excreted. 

Sources of good bacteria

As mentioned in an earlier post, healthy bacteria are called probiotics which can be found in the following foods:

  • Fermented foods like yogurt, kefir, sauerkraut and cheese,
  • Foods high in omega 3 fats like oily fish,

Prebiotics are food that is digested by your gut bacteria and keeps them healthy. They have been shown to reduce stress hormone in humans:

  • High fibre foods like nuts, seeds, whole grains, fruits and vegetables all contain prebiotic fibers that are good for your gut bacteria,
  • Foods rich in polyphenols which can improve cognition, like green tea, cocoa, coffee and olive oil.
  • Foods rich in tryptophan which is turned into the amino acid serotonin by gut bacteria.

Maintain your mental health 

Providing psychological advice is beyond the scope of this  website, but remember that your mental state can affect your entire body, including the most important part – your gut! Find ways to calm yourself. Constant worrying, negative and circular thinking, anxiety and stress will ultimetely affect your health. Peoples’ lives differ greatly and each person has to find what works for them. From my personal experience I can advise the following:

  • Start by being active as much as you can. Get exercise! It will make you feel better.
  • Breathe! Conscious breathing works miracles. With practice it can be utilized in times of high stress to help you centre yourself and stay calm. It becomes a “triggered response” with immediate benefits.
  • Meditate. Most meditation techniques also include breathing techniques. It does not have to be esoteric or strange. A boxer meditates when he visualises a fight before a competition. Just get your mind focussed.
  • Do yoga. There are a myriad different practices and they basically combine exercise with meditation.
  • Take a walk. A 10 minute walk does wonders for your mental health.

To conclude

The gut-brain axis is the physical and chemical connections between your gut and brain. There are nerves and neurons running between your gut and your brain. Chemicals such as neurotransmitters are produced in your gut but can affect your brain and your brain can induce the stress response affecting your gut.

Restoring a balanced gut by altering the types of bacteria in your gut can improve your general health including your mental health. Eat probiotic- and prebiotic rich foods (those that you are not intolerant to), and take supplements if necessary.

Look after your mental well-being by developing coping mechanisms and staying centred and calm. Keep doing it, like everything else it comes with practice.