Can emotions affect digestion and gut ? (and vice versa)

Can emotions affect digestion ? In recent years, there has been more talk about the connection between the stomach, gut (gut flora, microbiome) and brain (emotions and mood).

And given that the gastrointestinal tract is our “second brain,” where much of the immune system is concentrated, the topic deserves to be explored in a bit more detail.

Especially by people who subscribe to the notion that it doesn’t matter what we eat, as long as we get in our required caloric intake.

Gastrointestinal tract = second brain

In this article, we will often refer to gut, microbiome/gut flora/gut microbiome, and stomach as terms that address the same thing – the relationship between gut, microorganisms, stomach, mood, and health.

The gastrointestinal tract has the capacity to outperform all other organs in our body and even rival the brain.

It has its own nervous system called the enteric or visceral. Characteristically, it is made up of 50-100 million nerve cells, and it is a well-known fact that there are more immune cells in the gut than circulate in the blood or bone marrow.

Humans and the microbiome

We live in times where technology is becoming more and more advanced, and with its help we can detect and identify microbial populations on our skin, face, nostrils, mouth, etc.

The gastrointestinal tract, and the colon in particular, is home to the largest populations – more than 100 trillion microbes inhabit the gut flora, and that’s almost the same number of all human cells in the body if you include red blood cells.

In his book The Mind-Gut Connection, Dr Emeran Mayer, to illustrate the importance of the gut microbiome, says that if we put all the microbes together and shaped them like an organ, it would weigh between 1 and 3 kg.

By comparison, the brain weighs just over 1 kg.

This is why the gastrointestinal tract is often referred to as the “second brain” and some people also refer to it as the “forgotten organ.”

It is no surprise that the gut microbiome is of interest to scientists and that there is increasing talk about the relationship between it, the brain and our emotions.

Microbiome and emotions

The gut microbiome is in a prime position to influence our emotions by producing and adapting signals that are sent to the brain.

Whatever emotion arises in the brain, it affects the stomach/gut and the signals produced by the microbes back to the brain sometimes prolong the emotional state in question.

Communication between the microbiome and the central nervous system

In recent years, there has been increasing research between people suffering from mood disorders and the gut microbiota.

An interesting review summarizes published studies done on humans regarding the influence of the gut microbiome in patients with mood disorders.

Some of the findings at this point are that microbial diversity in people with emotional disorders are significantly altered relative to healthy individuals.

Bacteria producing short-chain fatty acids were found to be in reduced numbers in patients suffering from depression, while there was an increase in pro-inflammatory strains and those involved in fat metabolism processes.

Some studies have shown that specific bacteria are associated with clinical pictures, inflammatory profiles, metabolic markers and pharmacological treatment.

Brain-microbiome axis

The gut microbiome modulates brain development and function, and the brain in turn communicates with the gut via neuroimmune and neuroendocrine pathways, as well as with the nervous system.

This two-way communication system is called the brain-microbiome axis.

Through it, signals from the brain can influence physiological effects of the gut, including its motility, secretion, and immune function.

The signals that the gut microbiome in turn sends to the brain can influence its function in terms of regulation and state of moods and emotions.

In the BB-Team, we often address stress and why it is good to strive to not have it at excessive levels and more importantly to not be chronically exposed to high stress levels.

Chronic stress is also implicated in the topic of today’s article – it can affect the composition of the gut microbiome, which is associated with activation of the hypothalamus-pituitary-adrenal axis and an increase in inflammatory status.

Hyperactivity of this axis leads to cortisol secretion and an increase in the proinflammatory response.

The change in the microbiome directly affects the immune system and the disturbed balance between proinflammatory and anti-inflammatory cytokines affects brain function downstream.

Emotions show up not only on our face, but also in our stomach and intestines

We are used to our body language illustrating the emotions we are feeling at a given moment. They show up clearly on the face too and we don’t need to exchange lines to know if a person is angry or sad, for example.

The pattern of emotion is known because the brain sends certain signals to very small muscles of the face and so each emotion corresponds with a facial expression.

But how do these emotions affect the stomach and intestines? We can’t see them, but we can feel them.

If we are angry during traffic in a hectic city routine, for example, the brain sends characteristic behavioral signals to the digestive system – just as it sends signals to the facial muscles.

The digestive system, in turn, also responds dramatically.

If you’re angry at the driver in front of you and you literally want to scream in anger, your stomach starts to contract vigorously, which in turn increases stomach acid production and slows down the processing of the snack you had just before you left home and got stuck in traffic, i.e. the emotion in this case negatively affects digestion.

Stress and worry can lead to diarrhea or constipation.

Have you ever thought about how rich our language is when it comes to emotions and the stomach? The expressions “my stomach has tied itself in knots” and “I feel butterflies in my stomach” are associated with responses to specific emotions dictated by the brain.

Gut microbiome and neurotransmitters

Interestingly, the gut microbiome has the ability to secrete a series of neurotransmitters, such as:

  • GABA (an amino acid that ensures the normal functioning and recovery of the central nervous system);
  • Acetylcholine (a neurotransmitter involved in processes related to memory and concentration);
  • Serotonin (the happiness hormone);
  • Dopamine
  • Histamine (excitatory effect on the nervous system).

And like we said happiness hormone, more than 90% of the serotonin in the human body is produced in the stomach, which in turn can affect the regulation of emotions when delivered to the central nervous system.

It has been suggested that neurotransmitters secreted from the gut microbiome may affect the level of central neurotransmitters and then influence behavior and mood.

Why the food we eat is important

At the beginning of the article, we said that it deserves the attention of people who think that the type of food doesn’t matter that much as long as we get in a certain calorie and macro nutrient distribution.

When it comes to health, however, that’s not exactly the case.

  • The gastrointestinal tract collects information about the food we eat and does so 24/7, even when we sleep.

This information takes place in the stomach and at the beginning of the small intestine, where there are a small number of microbes. But in the large intestine there are trillions of microbes that digest the remaining nutrients to produce large numbers of molecules.

The good existence of microbes in the gut depends on the food we eat.

Interestingly, they are more or less programmed for their food preferences during the first few years of life. But regardless of their initial programming, they can digest anything we give them.

No matter what kind of food we feed them, they will use the vast amount of information stored in their millions of genes to transform partially digested food into hundreds of thousands of metabolites.

Dr. Emeran Mayer says that although we are only at the beginning of our understanding of the effects these metabolites have on the human body, we do know that:

  • some of them strongly affect the gastrointestinal tract, including nerves and immune cells;
  • others find their way into the bloodstream and are involved in long-range signals affecting every organ, including the brain.

In The Mind-Gut Connection, the following examples are given to illustrate the amazing topic that is the gut microbiome:

  • A fecal mass from an “extroverted” mouse is transferred into a “timid” mouse, resulting in the timid/shy mouse’s behavior becoming more similar to that of its donor, the gregarious mouse;
  • Transplanting faeces and their microbes from an obese mouse with an increased appetite into a thin mouse will turn the latter into the same overeating animal as the donor;
  • Consumption of probiotic-enriched yogurt (yoghurt) for 4 weeks, in healthy women, can reduce their brains’ response to negative emotional stimuli.

Accumulating more knowledge about the gut microbiome-brain axis and its relationship to the food we eat shows how the mind, brain, stomach and microbiome interact.

These intricate connections can make us vulnerable to disease, or they can help us maintain optimal health.

Healthy gastrointestinal tract

Once we understand how connected the brain and stomach are, to optimize gastrointestinal health and to take care of the diversity of the gut microbiome without creating conditions for dysbacteriosis, the following may help:

  • Reducing excessive stress levels, especially if we are frequently (chronically) exposed to it;
  • Practicing some meditation methods (if they harmonize our being) or some hobby that brings us joy;
  • Eating slowly;
  • Improving diet in favor of whole and unprocessed foods;
  • Avoiding or minimizing processed foods, artificial sweeteners and colors;
  • Eating a variety of fresh, seasonal and local fruits and vegetables;
  • Incorporating sustainable starch sources;
  • Intake of probiotic-rich foods (such as fermented foods);
  • Avoid eating under the influence of emotions such as stress, anger or sadness. Try to calm yourself down to some extent first.

If you have constipation, diarrhea or painful bloating for a long time, consult your doctor.

Sources used for Can emotions affect digestion :

  1. Current Understanding of Gut Microbiota in Mood Disorders: An Update of Human Studies can can emotions affect digestion
  2. Exposure to a Social Stressor Alters the Structure of the Intestinal Microbiota: Implications for Stressor-Induced Immunomodulationcan emotions affect digestion 
  3. The Mind-Gut Connection, Dr. Emeran Mayer