Beau Berman - July 2, 2021

The (almost) UNBELIEVABLE Relationship Between Your Mental Health and Gut Health 

Your gut health plays a crucial role in the quality of your overall health, including your mental wellbeing and cognitive functioning.

Poor gut health contributes to many health issues like stress, anxiety, and depression.

At some point, you have likely experienced signals from your stomach when you are feeling nervous, excited, angry, or anxious, like nausea or pain. This feeling occurs because, from stomach pains to feeling like you have "butterflies" in your stomach, your gut and emotions are closely intertwined at the gut-brain axis.

Your brain and microbiome are constantly in communication with each other. This constant communication means that when your gut is not feeling one hundred percent, the health of your brain will be impacted, and vice versa.

The relationship between your gut and brain can explain why you may literally feel nervous at times. For example, "flutters" in your stomach before giving an important speech, nauseous after getting in an argument with your best friend, or stomach pains when stressing about a big test. Your mental health is likely directly affecting your gut health. No, this does not mean that you are simply imagining your gastrointestinal issues. The health of your gut is physically affected by your psychological health, just like your mental health is psychologically affected by your gut health.

Psychological problems, such as stress, anxiety, or depression, can cause changes within the GI tract, like its movement and contractions.

The types of bacteria living in the gut, a physiological factor, can also alter the chemistry within your brain.

What is the Gut-Brain Axis?

The gut-brain axis is the point at which your brain and gut communicate with each other. They do this through your central and enteric nervous system, which links the emotional and cognitive aspects of the brain with peripheral intestinal functions (Carabotti et al., 2015).

As research on the relationship between the gut and the brain has become more advanced, it has become clear just how important the gut microbiota is in influencing this interaction (Carabotti et al., 2015). T

These two organs play critical parts in each other's physical and biochemical health. 

The Relationship Between Your Vagus Nerve and Nervous System

Your vagus nerve is an essential part of your parasympathetic nervous system (Breit et al., 2018). The vagus nerve acts as the supervisor to many crucial bodily functions, including your mood, immune health, digestion, and heart rate (Breit et al., 2018).

It also plays a vital part in connecting the brain and GI tract, sending information to the brain regarding the health of your inner organs (Breit et al., 2018).

One animal study found that feelings of stress or anxiety could act as a roadblock to the vagus nerve and brain (Carabotti et al., 2015). Because of this roadblock caused by the stress and anxiety, the animals experienced increased stress and GI tract issues. Two other animal studies found that when a fetus was exposed to prenatal stress, the number of good bacteria found in the gut was significantly decreased (Clapp et al., 2017).

This finding adds credence to the theory that stress can negatively impact the health of one's microbiome.  

"... stress can negatively impact the health of one's microbiome."

Stress impacting the gut microbiome

Neurotransmitters, the Gut, and Your Brain

The gut-brain axis has also been found to be connected through "chemical messengers" called neurotransmitters.

Neurotransmitters play a substantial role in controlling your feelings and emotions. Neurotransmitters can cause you to experience many different emotions such as fear, anxiety, stress, pleasure, sadness, and joy.

Believe it or not, many different types of neurotransmitters are produced within your gut by its cells and the trillions of microbes living within it.

For example, serotonin, the neurotransmitter responsible for feelings of happiness, is primarily produced within the gut (Yano et al., 2016). There are tons of other neurotransmitters that are produced within your gut.

These neurotransmitters include:

  • Gamma-Aminobutyric Acid (GABA), which contributes to improving feelings of anxiety, stress, and fear
  • Norepinephrine, which helps you wake up, promotes attention, and assists with memory storage
  • Dopamine, which allows you to experience feelings of pleasure
  • Acetylcholine, which plays a crucial part in maintaining high-quality memory and cognition
  • Melatonin, which plays an essential role in stabilizing your circadian rhythm and improving your sleep cycle
GABA (Gamma-Aminobutyric Acid)written in yellow and blue
neurotransmitters can impact mood

How Probiotics and Prebiotics Can Help Improve Both Your Gut and Mental Health

Probiotics can play a significant role in improving the health of not only your gut but your cognitive functioning and mental wellbeing, as well.

Due to the deep connection between your gut and brain, the improvements to your gut health initiated by probiotics can provide you with many mental and cognitive health benefits. The use of prebiotics and probiotics to improve one's mental health has been coined "psychobiotics" (Ansari et al., 2020).

The use of these psychobiotics has been linked to improvements in many mental health disorders, including anxiety, schizophrenia, Alzheimer's, depression, and autism (Ansari et al., 2020).

Studies have found that probiotics and prebiotic supplements can reduce the symptoms of both depression and anxiety. However, further research is still needed to properly understand which forms of psychobiotics are required and how they reduce symptoms. (Davani-Davari et al., 2019).

Prebiotics, including XOS, GOS, FOS, and inulin, have been found to affect mental health by boosting the effects a probiotic has on the gut (Davani-Davari et al., 2019). This effect can assist probiotics in protecting your brain from dementia while increasing your general cognition, recall skills, memory, learning ability, and mood (Davani-Davari et al., 2019).

This boost can also assist probiotics in providing a therapeutic effect in those experiencing autism (Davani-Davari et al., 2019).

Another prebiotic that has been found to have a crucial effect on mental health are human milk oligosaccharides (HMO). HMO is found in human milk and plays a pivotal role in providing nutrition to infants (Bode et al., 2009). HMO prebiotics are believed to give people many physical and mental benefits past the infant years, including the improvement of gut health. In addition, HMO has been shown to provide the brain with benefits to its cognitive functioning. 

"HMO prebiotics are believed to give people many physical and mental benefits..."  

Woman happy about HMO prebiotics

The Second Brain 

As the research related to the gut and mental health becomes more and more in-depth, the microbiome is beginning to develop a reputation as the "second brain."

The saying, "go with your gut," has started to make more sense as society develops a deeper understanding of just how much information our gut is sharing with our brain.

When our microbiome health is suffering, our mental health will begin to suffer, as well. Conversely, when we improve our gut health, our memory, recall, moods, and overall mental wellbeing will start to reap the benefits.

The relationship between your brain and gut is precisely why the use of prebiotics and probiotics can be crucial to maintaining your mental health and overall wellbeing.

As you have learned when we covered probiotics and the gut, probiotics can provide both your mind and body with many benefits. Many studies have observed the effectiveness of probiotics in helping to heal issues we are having within our gut.

As our gut benefits from the probiotics, the rest of our body can reap the benefits of a healthy and well-balanced gut. Our brain is one of the organs in our body that will reap the most benefits from probiotics.

They have been shown to assist in improving the brain's memory, recall, and overall health. Certain probiotics have demonstrated significant results in improving mental health and have been named "psychobiotics."

It may be surprising to read just how connected the brain is to the gut. It may even bring out your inner critic.

The research is out there, though, proving just how important the brain and microbiome are to each other.


Ansari, F., Pourjafar, H., Tabrizi, A., & Homayouni, A. (2020). The Effects of Probiotics and Prebiotics on Mental Disorders: A Review on Depression, Anxiety, Alzheimer, and Autism Spectrum Disorders. Current pharmaceutical biotechnology, 21(7), 555–565.

Breit, S., Kupferberg, A., Rogler, G., & Hasler, G. (2018). Vagus Nerve as Modulator of the Brain-Gut Axis in Psychiatric and Inflammatory Disorders. Frontiers in psychiatry, 9, 44.

Carabotti, M., Scirocco, A., Maselli, M. A., & Severi, C. (2015). The gut-brain axis: interactions between enteric microbiota, central and enteric nervous systems. Annals of gastroenterology, 28(2), 203–209.

Clapp, M., Aurora, N., Herrera, L., Bhatia, M., Wilen, E., & Wakefield, S. (2017). Gut microbiota's effect on mental health: The gut-brain axis. Clinics and practice, 7(4), 987.

Davani-Davari, D., Negahdaripour, M., Karimzadeh, I., Seifan, M., Mohkam, M., Masoumi, S. J., Berenjian, A., & Ghasemi, Y. (2019). Prebiotics: Definition, Types, Sources, Mechanisms, and Clinical Applications. Foods (Basel, Switzerland), 8(3), 92.

Yano, J. M., Yu, K., Donaldson, G. P., Shastri, G. G., Ann, P., Ma, L., Nagler, C. R., Ismagilov, R. F., Mazmanian, S. K., & Hsiao, E. Y. (2015). Indigenous bacteria from the gut microbiota regulate host serotonin biosynthesis. Cell, 161(2), 264–276.

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