Gut bacteria: How they influence our brain and mood

The realization that gut bacteria influence you in many ways is actually nothing new. The tiny microbes in your gut take care of your metabolism, digestion, and even influence your mood and state of mind.

Find out how this can be and why your gut is also called "the second brain" here.

1. Colonization of the intestine

Your gut is populated by trillions of bacteria, and that's a good thing. To be precise, about 100 trillion intestinal bacteria live in a single microorganism .

They reside in the mucous membranes of your intestinal walls and require an acidic environment to function. Researchers also call this construct the microbiome .

The hype surrounding intestinal bacteria and a balanced intestinal flora is currently greater than ever. Intestinal flora refers to the totality of all bacteria and microorganisms found in your intestines .

It is now known how important the microbiome in our intestines actually is and how far-reaching its influence is on overall human health : The microbes are not only digestive aids that process the food we eat, they also support the entire immune system and are closely linked to our mood and the production of important neurotransmitters in the brain.

Because of all these functions, the intestine and the microorganisms living in it are also called a " superorgan ."

BRAINEFFECT HACK: The majority of our happiness hormone, serotonin, is produced in the gut. A healthy gut flora therefore also influences our daily well-being . That's why BRAINEFFECT has developed DAILY GUT , which supports a healthy gut flora with friendly bacteria, vitamins, and fiber .

2. Intestinal bacteria – what types are there?

First of all, you should know that the composition of the microbiome varies from person to person . Not everyone has the same number of gut bacteria, which can be attributed to a variety of factors .

It starts with origin and birth and ends with diet , sleep , stress , hygiene , and environmental conditions . It is said that about half of all intestinal bacteria in every person are the same , but the rest is as individual as the person themselves.

But what types of intestinal bacteria are there? Basically, there are both "good" and "bad" intestinal bacteria . The bad intestinal bacteria are called coliform bacteria or putrefactive bacteria and can cause diarrhea and intestinal problems .

The good bacteria , on the other hand, are called pro-cultures and include lactobacilli and bifidobacteria . They ensure that the intestinal flora and digestion function as intended and are responsible for the human body's ability to absorb valuable nutrients and vitamins from food.

Both types of intestinal bacteria should always be in an appropriate ratio to each other , with the proportion of pro-cultures clearly predominating.

If this is not the case and coli bacteria have colonized large parts of the intestine, then in addition to digestive problems , other complaints can also occur that at first glance are hardly associated with the intestine.

These include poor concentration , decreased performance , and fatigue . A balanced intestinal flora is therefore important if you want to stay fit and productive.

3. The gut-brain axis

You've probably listened to your gut feeling before, or had something upset your stomach ? These sayings aren't unfounded—quite the opposite.

A growing number of researchers around the world are investigating how the gut microbiome influences what people think and feel .

Scientists at the University of North Carolina have now discovered that the accumulation of bacteria, or the condition of your intestinal flora, can be linked to your mood. [1]

To understand how this works, you first need to know how the gut and brain " communicate " with each other. Gut-brain-gut communication occurs via the gut-brain axis, and in both directions.

The main route is via nerve connections in the spinal cord , another route is via the vagus nerve , which runs from the brain stem to the digestive system and is involved in many regulatory processes in the intestinal tract.

Experiments with mice have shown that the vagus nerve also functions as a direct link between the microorganisms in the gut and the central nervous system (CNS). This is where the term "microbiome-gut-brain axis" is emerging.

The enteric nervous system (ENS), a network of nerve cells that runs through the intestinal wall, is also essential in microbiome communication.

In the ENS and elsewhere in the body, neurotransmitters synthesized by intestinal microorganisms are perceived by chemosensors, for example, and can thus communicate and transmit information with the vagus nerve and downstream structures such as the brain.

Another means of communication between the gut and the brain is through hormones such as GABA , neuropeptides and dopamine , as well as through products produced by intestinal bacteria, which can therefore be regarded at least in part as messenger substances.

These include, for example, short-chain fatty acids (SCFAs) and tryptophan . With the expansion of the gut-brain axis to include the microbiome, the microorganisms that communicate with the CNS are now also called the "psychobiome."

4. How your gut affects your mood

Researchers at Cork University in Ireland agree that gut microbes influence your brain and mood through various mechanisms. [2]

They discovered that intestinal bacteria are important building blocks for neurotransmitters such as serotonin ,dopamine and GABA , all of which play an important role in mood.

If your intestinal flora is out of balance , this can negatively influence the production or conversion of important neurotransmitters .

In the case of the neurotransmitter GABA, this is especially important for counteracting the symptoms of stress and for restful sleep. GABA is only properly synthesized by the bacteria in the gut and ensures that you wind down and sleep well in the evening.

Things get particularly interesting when you look at the connection between serotonin and the gut. The intestinal bacterium Bifidobacterium infantis is involved in the synthesis of tryptophan , the basic building block of the hormone serotonin.

Over 95% of this building block is produced in your gut and not, as is often mistakenly assumed, in your brain. Based on this knowledge, research has begun into how to positively influence the intestinal flora.

Perhaps the best-known human study was conducted at the University of California, Los Angeles, and suggests that proculture capsules may be helpful. [3]

Twenty-five healthy women were tested. For four weeks, 12 of them ate a cup of yogurt twice a day, while the rest did not. Yogurt contains pro-cultures, live strains of bacteria—specifically, Bifidobacterium, Streptococcus, Lactococcus, and Lactobacillus.

Before and after the study, the subjects underwent brain scans to measure emotions such as happiness, sadness, and anger.

The results were very surprising, as they showed significant differences between the two groups, with the yogurt test group consistently showing more positive emotions.

5. The gut and stress

There is a reciprocal relationship between the gut and stress . On the one hand, our psyche influences our gut . During periods of stress, many people react with digestive problems, cravings, or even loss of appetite.

The reason for this is that in stressful situations, increased levels of adrenaline and the stress hormone cortisol are released . Consequences include, for example , increased breathing and heart rate .

For these functions, the body requires enormous energy reserves, which are then withdrawn from the gastrointestinal tract. As a result, normal gastrointestinal functions are carried out at a reduced level.

This can result in symptoms such as nausea, abdominal pain, or diarrhea. Why each individual's gut reacts differently to stressful situations is not fully understood scientifically, but it is part of psychosomatic research.

A further consequence of the increased release of stress hormones could be a change in the composition of intestinal bacteria.

Noradrenaline, for example, could affect bacterial gene expression or communication between different bacteria, which could lead to a change in bacterial activity. [4]

On the other hand, the evidence is becoming increasingly clear, or rather, there have already been indications in animal experiments that our intestinal bacteria can also influence our psyche in some way.

Altered composition of the gut microbiome can have various causes . They can shift the balance of good and bad gut bacteria , causing the good gut bacteria to die off, which in turn can lead to digestive problems (e.g., diarrhea).

The result: There is no longer complete and sufficient absorption of important nutrients such as vitamins, minerals, etc.

6. Leaky gut associated with stress

Endurance athletes and people in very stressful jobs , such as board members, often develop digestive problems such as diarrhea, abdominal cramps and concentration problems due to high performance pressure and stress .

In connection with such complaints, a leaky gut is often found, which represents a functional change in connection with various damaging factors.

This causes the intestinal mucosa to become more permeable . The cause of a leaky gut is reduced blood flow to the intestine during strenuous physical activity, as more blood flows to the arms, legs , and heart.

As a result, the intestines can dry out , resulting in cracks in the intestinal mucosa , and allowing pests and germs to circulate more easily in the blood and lymphatic system. This can cause swelling in the intestinal wall.

Nutrients therefore require a longer transport time and may not be sufficiently absorbed by the intestinal mucosa because they are released back into the blood too early (and in their biologically inactive form).

On the other hand, a leaky gut can also cause harmful substances to enter your bloodstream , which puts a strain on your liver.

The consequence is that these steps require an enormous amount of energy, making you feel as if someone had simply pulled the plug on you. The main consequences are fatigue, exhaustion, and a drop in performance.

Your gut is extremely important for performance, as some gut bacteria are associated with increased production of butyrate, a short-chain fatty acid (SCFA) that serves as an energy source for our intestinal cells. Butyrate can increase transepithelial resistance, leading to an improved intestinal barrier.

7. Intestinal cleansing – what can you do to maintain a healthy intestinal flora?

There are ways and means to rebalance an imbalanced intestinal flora and, in a sense, to rehabilitate the gut. Here are our do's and don'ts:

DOS

Fresh foods such as vegetables in particular contain the so-called pre-cultures , but luxury foods such as chocolate and coffee are also rich in them.

These food components are not immediately utilized by the body, but initially remain in the intestines and serve as food for the intestinal flora , or so-called probiotics. Not to be confused! Probiotics refer to those active bacterial strains that you maintain with a proper diet .

This is the second useful tip for a healthy intestinal flora. Dairy products like yogurt contain the bacterial strains that you simply multiply in your intestines by consuming them.

BRAINEFFECT HACK: An ideal breakfast for a healthy gut flora is yogurt with fresh strawberries and DAILY GUT . Or as a sour-fruity drink with DAILY GUT LEMON . This gives your gut exactly what it needs, and the fruity and delicious breakfast is quick to prepare.

DON'Ts

Certain foods such as granulated sugar and highly processed carbohydrates have a negative impact on the ratio of intestinal bacteria.

Carbohydrates are not necessarily bad , it is usually just the way in which they are processed that causes the micronutrients that are important for the intestinal flora to be lost .

Therefore, try to rely on carbohydrates in their natural form, such as potatoes, sweet potatoes, and root vegetables.

Want to learn more about gut bacteria? Then listen to our podcast on "Your Second Brain Has a Mind of Its Own" with gut expert Dr. Emeran Mayer.

The US researcher and author of "The Second Brain" explains how the gut influences our mood and why it is the most important part of our digestive tract.

8. Talking Brains Podcast Episode #05: "Your Second Brain Has a Mind of Its Own" - Interview with Gut Expert Dr. Emeran Mayer

9. Conclusion

Our gut and brain are more closely connected than many people realize. The composition of the microbiome, i.e., the totality of gut bacteria, can affect your mental and physical performance. Likewise, your mental state can also affect your gut bacteria.

10. Sources

[1] Lyte, M. (2013) Plos I Pathogens. Microbial Endocrinology in the Microbiome-Gut-Brain Axis: How Bacterial Production and Utilization of Neurochemicals Influence Behavior. Vol. 9. Issue 11: e1003726 [ http://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1003726 ]
[2] Cryan, J.; Dinan, TG (2012) Nature Reviews Neuroscience. Mind-altering microorganisms: the impact of the gut microbiota on brain and behavior. Vol. 13, pp. 701-712 [ http://www.nature.com/nrn/journal/v13/n10/full/nrn3346.html ]
[3] Tillisch, K.; Labus, J. et al. (2014) Gastroenterology. Consumption of Fermented Milk Product With Probiotic Modulates Brain Activity. Vol. 144. Issue 7. [ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3839572 /]
[4] Wang, H.; Lee, I.-S. et al. (2016) Journal of Neurogastroenterology and Motility. Effect of Probiotics on Central Nervous System Functions in Animals and Humans: A Systematic Review. Vol. 22. Issue 4, pp. 589-605. [ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5056568/ ]