The Effect of Gut Bacteria on Mood

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You may have heard lots of talk recently about the importance of having a “healthy gut.” This is an emerging area of research and scientists are continuing to discover precise reasons why the gut (aka gastrointestinal system or GI tract) is one of the most important biological systems in the human body.

[Note: Terminology can vary when talking about gut health. For instance, intestinal flora (or gut bacteria) is often referred to as “microbiota,” and the biological system comprising these trillions of organisms is called your “microbiome.” In other words, you have trillions of microbiota in your microbiome, which reside in your GI tract, or gut. Another common term used to describe the beneficial / good gut bacteria is “Probiotics.”]

Here are just a few of the important discoveries researchers have made about the gut:

  • The majority of nutrient and water absorption takes place in the gut.
  • Around 20 hormone processes are connected to or have processes in the gut.
  • The GI tract contains more than 1 billion nerve endings and has more surface area than that of your external skin. These neurotransmitters, known as the enteric nervous system (ENS) are so involved in your body’s processes, scientists have nicknamed the gut the “second brain.”water and nutrient absorption takes place in the gut
  • There are over 100 million neurons in the ENS; more than the spinal cord, or the peripheral (outside of the brain or spinal cord) nervous system.
  • The brain doesn’t need to operate the GI system. The second brain can act independently. In some cases the ENS sends signals to the brain, not the other way round [1].
  • The “gut-brain axis” describes the influence the gut, microbiome, and ENS have on the brain, including both emotional and cognitive functions [2].
  • The gut contains 70% to 80% of your body’s immune cells.
  • The GI microbiome prevents colonisation by potentially pathogenic (“bad”) microorganisms, provides energy for the gut wall from undigested food, and it regulates the mucosal immune system [3].
  • GI microbiota contribute to energy homeostasis (stability), prevent mucosal infections and, importantly, contributes to the maintenance of an intact GI barrier, which seems to be closely related to infectious, inflammatory, and allergic diseases [4].
  • Any disruption to the harmony of the GI microbiome affects the function of the host’s (your body’s) defense systems.

Can Your Gut Health Impact Your Mood?

Probably the most surprising effect the Gut-Brain Axis and microbiome have on your body is that to do with mood [5].

Science has long-recognized much of our supply of neurochemicals originate in the intestines. Most of your serotonin is made there [6], as well as approximately 50% of dopamine.

However, it’s only recently that serious consideration has been given to the role our microbiota (the bacteria in the gut) play in creating those chemicals [7,8].

A 2015 story in The New York Times shares interviews and quotes with several scientists on the cutting edge of this area of research, including one of the first to propose the neurochemical aspects of the gut-brain axis − Mark Lyte, a microbiologist at the Texas Tech University Health Sciences Center [9].

Lyte and other researchers have found that among the many chemicals secreted by our microbiota, some are identical to the substances “used by our neurons to communicate and regulate mood, like dopamine, serotonin, and gamma-aminobutyric acid (GABA).

These, in turn, appear to play a function in intestinal disorders, which coincide with high levels of major depression and anxiety [10].”
research into the connection between gut bacteria and mood

For example, in 2014 a group of Norwegians studied the feces of 55 people, noting depressive patients had certain bacteria in common.

It’s due to this type of research that it’s becoming more commonly accepted that anxiety, depression, and several pediatric disorders, including autism and hyperactivity, are linked to gastrointestinal abnormalities [11].

It was once thought that stress caused the immune system to be weakened, which in turn affected how bacteria in our microbiome behaved. Now, somewhat revolutionarily, research indicates that certain bacteria actually cause stress, which then impairs the immune system.

The truly exciting aspect of all this science is work that Lyte and his peers are doing in the realm of reversing disorders. For instance, using the secretions of certain bacteria to relieve anxiety and elevate mood by putting the microbiome back into harmony—proposing probiotics (beneficial, life-giving organisms) can be tailored to treat psychological disorders. These are somewhat flippantly being referred to as “psychobiotics [12].”

One exciting study carried out in Sweden found that mice raised without microbes were far more active outside. Not only that, the microbe-free mice were observed to have less anxiety and be more daring overall.

Serotonin is a known factor in mood, anxiety and depression, to name a few of its functions [13,14]. The connection to the manufacturing and body’s use of this essential chemical (some consider it a hormone) is gaining increasing attention. Or, as a 2015 publication in Behavioral Brain Research stated [15]:

“The brain-gut axis is a bidirectional communication system between the central nervous system and the gastrointestinal tract. Serotonin functions as a key neurotransmitter at both terminals of this network. Accumulating evidence points to a critical role for the gut microbiome in regulating normal functioning of this axis … There is also substantial overlap between behaviors influenced by the gut microbiota and those which rely on intact serotonergic neurotransmission.”

More research is being done to identify the precise processes occurring, but it’s certainly becoming crystal clear… the health of your microbiome is essential for even your mental and emotional wellbeing [16].

One way to help support your gut health is with a quality probiotic supplement such as Organixx ProBiotixx+.

Organixx ProBiotixx+ formula contains a single, super-strain of Lactobacillus plantarum, designed to help alleviate constipation… eliminate gas and belly bloat… support your entire immune system… and give you total digestive protection.

Organixx ProBiotixx probiotic formula

Article Summary

  • The GI tract contains more than 1 billion nerve endings and has been nicknamed the “second brain.”

  • The “gut-brain axis” describes the influence the gut, microbiome, and enteric nervous system have on the brain, including both emotional and cognitive functions.

  • Anxiety, depression, and several pediatric disorders, including autism and hyperactivity, are linked to gastrointestinal abnormalities.

  • Secretions of certain bacteria can relieve anxiety and elevate mood by putting the microbiome back into harmony.

Reader Interactions


  1. Pretty amazing research!
    What does this mean for people on long term medication with mental illness diagnosis?

    • It implies that probiotics could have a place in the longterm treatment modalities. However, since it is an “emerging” area of research, we likely won’t know the full impact for decades to come. Very exciting stuff!

      • It’s only “emerging” here in the USA. Other countries have been consuming probiotic foods for thousands of years and already know about their health benefits. Glad we’ve finally recognized it. 🙂

    • I am involved with a small fertiliser company in NZ. I do some research and write a monthly column, generally about how fertiliser impacts on the environment, but also articles similar to this one. Is it any wonder that our gut affects our mood?
      The link between soil and human gut microbes
      There is no doubt that human gut microbes play a major role in determining the health of their host. Hippocrates (460-370 BC) stated “All diseases begin in the gut”. A very small sample out of a huge list of these diseases is colic, bloating, flatulence, vomiting, diarrhoea, dyslexia, asthma, allergies, autism, eczema, constipation, depression, arthritis, ADHD, schizophrenia, heart disease, tooth decay, cancer and bowel diseases. The father of modern psychiatry French psychiatrist Phillipe Pinel (1745–1828) correctly stated in 1807. “The primary seat of insanity generally is in the region of the stomach and intestines.” In a healthy adult, there are 1.5-2.0 kgs of microbes jostling for order. Exactly what order they achieve, and the degree of host comfort or discomfort depends partly on our individual diet, and unfortunately partly on food growers’ and processors’ actions. We rely on up to 100 trillion microbes. A well-functioning gut holds the key to our health. Just as a tree with sick roots will not thrive, nor will our bodies or minds thrive without a well-functioning digestive system. Livestock are no different.
      Soil microbes influence the health and defence mechanisms of plants. Guts and roots have large surface areas, with microvilli and folds or root hairs in some parts. Both roots and guts are structured, non-homogenous habitats with pH, nutrient, water, and oxygen differential levels or gradients. Gradients favour colonization by distinct bacteria that are more successful in some root or gut regions. The more diverse and balanced the gut and root zones are, the better health the hosts will enjoy. Bacillus subtilis, also known as the soil bacteria was first used in the 1940’s to protect troops from dysentery and typhoid. It is resistant to stomach acid and most antibiotics. It has strong immune-stimulating properties and is particularly effective with allergies and autoimmune disorders. Its enzymes are anti-fungal, anti-viral and anti-bacterial. It is not a resident of humans, but is transitional, doing a lot of good as it passes through. It is also the microbe that can clean up the effluent pond. Probiotics containing Bacillus subtilis are the most effective you can get.
      Dr Linus Pauling (1901-1994), winner of two Nobel Prizes, stated: “In my opinion, one can trace every sickness, every disease and every ailment to mineral deficiency.” It is logical then, that plant and stock health problems and ensuing chemical intervention are caused by poor fertiliser practices. Fruit and vegetables that do not store lack fertiliser integrity; run-out pastures; effluent pond problems and failures are directly related to incomplete or poor fertiliser practices. In recent times there have been outbreaks of pests and diseases; porina, army worm, Psa, aphids, facial eczema and toxic swedes to name a few. These are symptoms that the soil microbes and plant roots are not being fed a balanced diet. When the soil is balanced properly, these problems do not happen unless chemicals or GM are involved. The problems are, in fact, self-inflicted. Fertilisers and food can stimulate microbes, so why are the wrong microbes being stimulated in the majority of cases?
      Glyphosate, an antibiotic is used to prepare feed for animals and humans. The plants and animals or their products end up as human food. Among many other negatives, glyphosate reduces manganese in the rhizosphere by disrupting microbes. Lactobacillus levels are low in the human gut in association with autism; this creates a vacuum that allows pathogens to overgrow causing ill-health. Lactobacilli normally have high intracellular levels of manganese which enables them to control toxic oxygen bacterial species. It has been found that autistic children have 60% less manganese than they need. Similarly, reproductive capacity of animals is reduced as uteruses atrophy through lack of manganese. Sperm count is also reduced.
      Glyphosate has decreased brain levels of vitamin B12 in elderly, autistic and schizophrenic people. Subjects with both autism and schizophrenia have three-fold lower levels of vitamin B12 in the brain. B12 deficiency also causes dementia. Nutrition of Lucerne through one glyphosate spray the previous season, has reduced boron 18%, calcium 17%, copper 20%, iron 49%, magnesium 26%, manganese 31%, nitrogen 13%, phosphorus 15%, potassium 46%, sulphur 52% and zinc 18%. Those people suffering any of the diseases listed above are similarly affected, as their gut microbiome is unable to properly process minerals. Imagine how much more productive everything would be with correct fertilising and fewer chemicals.

  2. Hi
    Just wanted to ask if the multivitamin with Fulvic acid i am taking is enough for my daily intake?

  3. LS, as I suffer from chronic diarea for years and even after many medical examinations (colonoscopy and scans)my internist told me: may be you belong to aspeial type of peole we cannot help..So may be you can do for me something..

    • I suffered this way, Bertha. I finally discovered I was allergic to soy. Soy is in many things not just protein drinks. As soon as I quit the soy drinks I started getting better. I now read labels on everything. I feel better in my 60’s than I did in my 20’s and 30’s. This may not be your problem but it is a place to begin. I was surprised to find soy in ice-cream. Also, in nutritional products. I wish you the best in finding your answers.

    • One of the main causes of chronic diarrhea are intestinal protozoan based infestations. These are often difficult to diagnose. Sometimes naturopathic physicians can be helpful if they use bioresonance based testing. This happens in pets as well. I have treated many and have been successful in resolving chronic diarrhea where veterinary internists have been unsuccessful (a similar scenario). Dr. D Tim Crowe
      * this is not meant to diagnose or treat or suggest or guide health care; what is written is the authors opinion only.

  4. I heard that you should not do oils internally ….very confused is this true as I was diagnosed with breast cancer and I use Frankincense but they told me there is no research on this could you please help clear this up for me, as I follow all your videos and have many of your ebooks and try and keep up with both of you and love it ….what do you recommend …I know you can not make any claims, I am aware of what is happening but what oils are good and bad I not sure, need some help in this area ….Thanks Sue

    • Hi Sue, I looked at this the other day and apparently the English study belief is you can’t take oils internally and the French study belief is that you certainly can. Both are based on different methods. Look at ‘doTerra’ range. I saw a webinar recently and have been looking into it myself. I hope that is of some help.

      • Indeed two ways the English and the French ( Orly) so feel what is right for you. I would take CBD oral as from yesterday if I were you.

    • Hi Sue,
      Pure essential oils may be taken internally (but not all). You must be very careful where you purchase your oils as the FDA does not regulate them. If they are cheap, they are probably mostly synthetic and will say on the bottle “not for internal use”. Frankincense is one oil that can be taken internally. There are numerous studies on Frankincense and cancer…just google it. It’s a wonderful oil!

  5. so what do I have to do, to be I agood mood and how do I drain the swamp in my gut – so that it functions like I was 10

  6. My mother slowly changed as a person over many years, she was not herself you could say. The family noted aggressiveness and anxiety, ramming talk and moodiness then came the muscle control issues and tics. Dementia was considered. She deteriorated rapidly ending in hospitalisation in a near uncontrollable paranoid state.
    Celiac – after a year to diagnose then two years to stabilise my mother was living independently again and managing entirely on her own. And MOST important of all, she was the person I knew as my mother who lived independently another 11 years until age 84.
    There are NO medications for Celiac, it is ALL nutrition and as a Psychologist it questioned much of what I had learnt about personality, character, attitudes and behaviour. Fix nutrition first.

  7. I have suffered from anxiety and depression on and off all my life but function with that and a busy family life. I decided to start doing coffee enemas for a time due to family health issues. On one occasion after feeling quite down and sluggish I decided to do an enema. Immediately following I had the most amazing energy surge that lasted the day. My life seemed to sparkle for that time! I have wondered why, on that particular day I felt so amazing afterwards and I can perhaps conclude it may have been due to the removal of some nasty bacteria from my gut?!! Fascinating stuff!

  8. I have acid reflux and take Omoprazole every day for over 5 years now. There’s a whole list of side effects with osteoporosis and malnutrition being the main ones. I need to stop taking them but when I don’t my stomach feels inflamed after anything I eat. Is there some natural remedy for this?

    • Hi Cindy have you tried taking milk kefir? It is rich in probiotics and has a calming effect on you digestive system.

    • My wife was taking this stuff every day too, except in New Zealand it’s called Losec. I found a product called Digest RC (black radish and other components) that she now takes before the evening meal. She has now almost completely weaned herself off Losec and she’s very happy about that. PPIs such as Losec and Omeprazole have never been tested for long term effects because they were originally intended for short term use only.

    • I had taken omeprazole for YEARS, along with other meds. Started having nearly every bad side-effect on the lists and went “cold turkey” from them all–started trying to just wean off, take less, but it wasn’t happening quick enough. Heard turmeric could help wean from the omeprazole and tried it–very cautiously. My GERD isn’t perfect, but mostly isn’t even there unless I stuff myself!

    • Taking a spoon of raw, organic apple cider vinegar in water every day got rid of my acid reflux, and its a natural probiotic too. In addition, the digestive enzymes from Epigenetic Labs, (now Organixx), after a heavy meal are a God send. Please try to get off those meds. God Bless.

  9. we, as human beings are totally surrounded,, and outnumbered by the medical establishment and big pharma, and and big corporations. We are not only in the last line ,when it comes to information, but “they” are trying to advertise us out of doing whats best for our health, “they” really don’t want us to know what that is.
    Thank God!! for people like you all who are trying to inform the masses!
    Perfect example of what I said is the very fact that other countries are way ahead of us(in nutrition) in the US, where we are suppose to be free,. thanks for the soap Box, I’ve been on anti-biotics most of my life and now, for the last 30yrs, had to be on anti-depre ss & anxiety meds

  10. Cindy , have you been tested for the H-pylori bacteria? Your description
    sounds like that is your problem. A Dr. would need to diagnose you

  11. Hi, Cindy. By experience l can tell you, if you eat two purple raw potatoes a day, immediately you will stop taking imeprazole.

    • Hi Elza, your reply to Cindy is quiet interesting. We are used to consuming raw food such as green vegetables, radish, carrot, tomatoes and sprouted beans etc, but I have not heard potato to eat raw because we are told by our seniors never take potato not cooked. Will you tell me what is that chemical in potato to replace imeprazole?

  12. I have a hard time understanding this ..There is so much information that concerns life and then making it longer. I do not see any of this on tv, or commercials, you would think that the people in this business would want to produce this at the watcher’s expense me and all the subscribers and the advertiser’s expenses as well.The only thing I see is commercials we don’t need to be repeated on a minute basis. There are only 45 minutes of programming and 15 minutes of repeated commercials.There is more info on space than life itself.Is it really more important than keeping live better for all .I will never go into space, but would like to live healthier and a little longer. So lets get this kind of info in the regular programing and less comercials,for the benefits of health.i do hope you understand what I am getting at.We need more of this information than what we are watching on tv now and the next generation could learn as well from watching .

  13. The title of your e-mail “wether certain foods could affect the mood”
    is not being dealt with adequately. Instead one has to work through pages and pages until your advertisment emerges.
    I am tired of reading stuff like this.
    I would prefer clear cut clean information.

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