Why the Gut Microbiome is crucial for your Mental Health

Why the Gut Microbiome is crucial for your Mental Health

Published: 21 May 2021

Updated and medically reviewed: 29 October 2022

Dr Monique Hope-Ross and Dr Paul B Chell


Gut Bugs: What are they?

Bugs are small organisms, made up of single cells, and they have been around a lot longer that humans. They were the earliest forms of life, and appeared over three billion years ago. You live with trillions of bugs in your guts. Your gut bugs outnumber your own cells, weighing in heavier than your brain!

Gut bugs beat you on many fronts: genes win prizes, genes are the controllers and instigators of manufacturing and you have a measly 30,000 genes; your gut bugs beat you two hundred-fold with millions of genes. Not just that, you are outnumbered by your gut bugs. You have 31 trillion human cells, unless you are an alien, and your gut bugs number over 38 trillion cells.

With this vast number of cells and genetic power, your gut bugs have the power power to exert a major effect on you. They have more influence over you than you imagine!

Who speaks to your Brain? That’ll be your gut and gut bugs

Your gut constantly speaks to your brain. How about that fluttering feeling in your stomach, just before you get on stage? That’s your gut and brain communicating with each other.

The vagus nerve, or wandering nerve is the longest cranial nerve, and it runs from the brain, through the face, neck, chest and abdomen, to supply the entire gut. Back in the 80s, we were taught in medical school, that the vagus nerve was a one-way system, the brain very much being the master; messages were transmitted from the brain to to the gut, and the gut was silent. But it is now known, that is not the case; the vagus nerve is very much a two-way system, and the gut sends and receives messages to and from your brain, via this information highway.

Your gut bugs also communicate directly with your brain, in several different ways.

  • Gut bugs send messages directly to the brain via the vagus nerve, by exciting tissues in the gut lining to stimulate the nerve.
  • Gut bugs secrete important chemicals (hormones and neurotransmitters) directly into the blood, which are then transported to the brain.
  • Gut bugs activate hormone producing cells in the gut lining, which affect your brain.
  • 70% of the immune system and immune cells are located in the gut. There is constant crosstalk between your immune cells and your gut bugs and in turn your brain.

This extensive communication system is called the Microbiome-Gut-Brain Axis. As with any effective communication system, continuous rapport allows gut bugs to exert a major influence on your brain.1

Gut bugs are composed of 38 trillion microorganisms

Gut bugs are composed of 38 trillion microorganisms, which include bacteria, viruses and fungi. They are highly interdependent, there are hundreds of different species and in health, the good bugs keep the bad bugs in check.

What do gut Bugs do?

Your gut bugs provide you with thousands of essential chemicals; chemicals, which you can’t make, and on which your life depends. Humans have evolved with gut bugs for millions of years and we have an interdependent relationship; they need us, and we need them.

Many of the chemicals produced by gut bugs act on your brain and nervous system, these chemical messengers or neurotransmitters act as hormones. The messengers include serotonin, dopamine, adrenaline, tryptamine and short chain fatty acids. The production of these chemicals needs coordination between your gut, brain and gut bugs.

Serotonin, produced in the gut gives you a mood boost. It makes you feel satisfied, happy and optimistic. In simple terms, if you have too little serotonin, you become depressed; if you have the right level of serotonin then your mood is good. Healthy gut bugs play a key role in controlling serotonin production and in maintaining the right level of serotonin; ramping up and down production depending on your need!

How bugs affect your mood

Gut bugs change your mood by the production of neuroactive chemicals, which are then absorbed into the circulation. Cryan et al were amongst the first group to show that gut bugs influence our emotions.2 They introduced the concept of the psychobiome; these are the gut bugs that alter how you think, feel and act. They showed that your gut bugs can affect your brain function! What happened to free will? They also showed that people who are depressed have a different composition of gut bugs than people who are not depressed.

Short chain fatty acids are among the many neuroactive chemicals produced by gut bugs. Whilst having a myriad of effects, these short chain fatty acids affect our mood; gamma-aminobutyric acid helps to control feelings of fear and anxiety and propionate is involved in satiety.

How can it go wrong?

When you are in harmony with your gut bugs; your body is a temple, poetry in motion: you feel great, you look young, and you move easily. But it can all go horribly wrong, with disastrous consequences for your health.

There is an established association between brain disease and bowel symptoms, recognised for millennia; Plato said, “All diseases begin in the gut”. Parkinson’s disease is associated with constipation, and constipation can be the first sign of this illness. Irritable bowel syndrome is associated with psychological symptoms, depression is associated with digestive symptoms and the list goes on. And gut bugs are one of the key players in the link between gut and brain diseases.

When you are in harmony with your gut bugs; your body is a temple, poetry in motion: you feel great, you look young, and you move easily. But it can all go horribly wrong, with disastrous consequences for your health.

Diet plays a role in mental health, and this association involves the role of gut bugs.3 Changes in gut bugs have been identified in autism, schizophrenia, and attention deficit disorder, as well as mood disorders such as depression, anxiety, and stress. Both Alzheimer’s disease and Parkinson’s disease have been linked to gut bug changes. Children with autism have abnormal and fewer species in their gut bugs.

In the Flemish Gut Flora Project, the presence of butyrate producing bugs were consistently associated with a higher quality of life. Depletion of butyrate producing bugs was associated with depression.4

We all suffer stress, but some people become anxious, and others do not. We tend to admire people who show this characteristic, but maybe we should admire their gut bugs instead? Bear et al performed a metanalysis of studies, which looked at the relationship of stress resilience to gut bug composition.5 Stress resilience is the ability to withstand stress without developing anxiety, depression, or mood disorders; a characteristic badly needed in modern times. While many factors influence your response to stress, gut bugs are emerging as a significant player. Good, healthy gut bugs confer increased stress resilience.

The relationship between sick gut bugs and mental disease is building, and the topic is still one that requires further work. But there is increasing evidence that characteristic gut bugs changes are related to mental disorders. Whether the gut bugs changes are the cause or effect remains to be confirmed.2

Does helping gut bugs help mental disease?

Medications used for mental diseases do not work in everyone and these tablets frequently have unpleasant side effects. Furthermore, drug withdrawal can be difficult. This has led to the search for safer, more effective treatments. Gut bug based treatment for mental health is a new exciting field, with huge promise. The terms nutritional psychiatry or psychobiotics refers to the direct treatment of gut bugs in the management of mental disease. Medics are talking excitedly about a psychobiotic revolution. Evidence is building that targeting gut bugs is not only safe but also effective in the management of mental heatlh.

The treatment of gut bugs involves either the use of prebiotics with or without probiotics. Prebiotics are high fiber food such as green vegetables. Probiotics contain live bacteria and can be in the form of food, such as kefor or live yoghurt. The bugs can also be freeze-dried and administered in tablet form. Many studies have reported successes with such approaches to treatment.

Kefir Grains and Kefir

Kefir and Kefir Grains. Kefir grains are living cultures of bacteria complexed with a polysaccharide-kefiran. Kefir grains are not actual grains, such as wheat. Kefir is very easy to make at home, once you have a starter culture of kefir grains.

Yang et al, in a metanalysis reviewed the role of gut bug treatment in the management of anxiety.7 Anxiety may affect as many as a third of people in their lifetime. They report that 11 of 21 studies confirm the positive effects of treatment of gut bugs for anxiety. The studies where dietary adjustment, or prebiotics was the main approach were more successful than the studies using probiotic supplements.

Probiotics have been associated with positive outcomes in several trials evaluating the effect on mood. A probiotic mix treatment had a positive effect on mood in a study of healthy female volunteers.8 A healthy elderly population reported a positive effect on mood following probiotic treatment for three weeks with live yoghurt.9 A probiotic reduced exam stress levels in healthy students, after only two weeks of treatment.10

A healthy diet supports gut bugs and thus serotonin production. A study in Spain evaluating over 40,00 people showed that people who are not depressed have a healthier diet than people who are depressed.11 Similar findings in Canada in 25,000 people revealed that a healthy diet over the course of one year was associated with fewer physician visits for depression. As the diet score improved, there were even fewer visits for depression.12

Diet Whisperer Tip: Support your gut bugs by providing them with lots of fiber and eat lots of vegetables

Support your gut bugs by providing them with lots of fiber and eat lots of vegetables

Cryan et al studied a group of healthy people, who were divided into two groups. One group were advised to eat a psychobiotic diet. This consisted of vegetables, legumes, fermented foods and grains. The control group were advised to follow a diet, based on the healthy food pyramid. The outcome between the two groups was different. After only four weeks; those eating the psychobiotic diet, felt less stressed and their sleep improved, compared to the control group. This study shows that the food impacts our mood, and eating more fibre and fermented food may be an effective method of stress reduction.13

With the recent widespread deterioration in mental health worldwide, following the Covid pandemic, we need all the help that we can get. Psychobiotics is a very promising approach to this problem.

How do I support my Gut Bugs?

You can improve your gut bugs, you can help your gut bugs and make a difference to your life and your health. Gut bugs respond rapidly to changes in diet. A healthy diet for gut bugs includes a diverse range of foods with lots of different plants. Gut bugs feed on fiber and one of the keys to helping your gut bugs is to eat a lot of fiber. Fiber is found in vegetables, particularly green vegetables and also found in fruit, legumes, nuts and whole grains, such as couscous.

A healthy diet for gut bugs excludes super-refined carbs, such as sweets, biscuits, muffins, cakes etc. If you eat processed food, you encourage the bad bugs which then outnumber the good bugs and you are in a downward spiral of poor health.

Probiotics, food containing live bugs include live natural yoghurt, live cheeses (banned in USA!!!!), kefir, kombucha and fermented vegetables. These all support and help to develop and maintain gut bug colonies. Probiotics are available in tablet or supplement form, but if your diet is healthy, you do not need these supplements.

A healthy lifestyle with regular, good quality sleep and an EatSpan under 10 hours helps to support a healthy gut bug colony. Gut bugs like to exercise and blossom when you are fit!

Diet Whisperer Tip: Athletes have excellent gut bugs and gut bugs like to go for a run

Athletes have excellent gut bugs and gut bugs like to go for a run

What about antibiotics?

The misuse and abuse of antibiotics has heralded a modern health scare; resistance to antibiotics, and this problem is constantly in the news. But far more worrying to us here in Whisperer HQ, is the adverse effect that antibiotics have on gut bugs, in both humans and animals. Commercialisation of farming heralded the ubiquitous use of antibiotics in animal food, and the animals retain antibiotic residue, which we then consume. This can have adverse effects even in the tiny doses eaten.1 Worrying, isn’t it?

Antibiotics kill bugs and this includes gut bugs. Just think, you work hard for years cultivating your gut bugs and one course of misjudged antibiotics ruins all your efforts. It can take 6-9 months to restore a healthy gut bug colony, following a course of antibiotics. Sometimes the gut bug colony never reverts to normal, even after a single course of antibiotics. And researchers have confirmed an increase in depression in people taking antibiotics.

We have some advice on antibiotics: Use antibiotics only in serious or life-threatening illnesses. AVOID ANTIBIOTICS IF YOU CAN.

And Now?

Don’t expect to go to your doctor and be given advice about your gut bugs. It is all still a bit to new. But you can take your health into your own hands and there is no downside to looking after your gut bugs. So, why not start today and think about the 38 trillion cells in your gut, influencing your mental health and well-being in so many ways? You can think of them as a cottage garden, you will never regret tending your gut bug garden.

Summary

Gut bugs are intimately connected with your brain. In health, your gut bugs provide you with essential chemicals, but gut bugs need to be looked after and need the right food. Fiber is the key ingredient, and it is known that most people do not eat enough fiber. Deterioration of the gut bug colony is associated with mental health disease, including mood disorders. Research, is looking at treating mental health disorders by treating gut bugs, using psychobiotic diets and this is showing promise.

Aren’t you amazed that humans, as intelligent as we consider ourselves to be, are partially controlled by single cell organisms: your gut bugs!

Blog Whisperings

  • Gut bugs are critical for health-both mental health and physical health

  • Gut bugs have an effective communication system with the brain

  • Gut bugs produce chemicals which influence the brain

  • Gut bugs are involved in the production of the mood-altering hormone serotonin

  • Mental disease is associated with abnormalities of gut bugs

  • Due to the adverse effect of antiobiotics on your gut bugs, they should be used only when absolutely necessary.

  • Psychobiotics or nutritional psychiatry is the treatment of mental problems by directly targeting gut bugs

  • Gut bugs can be altered, supported, and improved by a healthy diet and lifestyle

  • You should eat a lot of fibre to improve your gut bugs.

  • Probiotics such as kefir, kombucha, fermented vegetables, live yoghurt and cheeses support healthy gut bugs

  • Supporting a healthy gut bug colony helps with mental health

  • Nurture your gut bugs, to reap tremendous health rewards

Please read: The information on this website is not intended to constitute medical advice, nor is it intended to replace or conflict with the advice given to you by your doctor or other health professional. Before embarking on the plans set out on this website, you should discuss them with your doctor, especially if you have any medical condition or if you are taking any medication. The author and publisher disclaim any liability directly or indirectly from the use of the material in our books and on our website by any person.

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