The Brain-Gut Connection

What Is The Brain-Gut Connection?

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Have you ever noticed that strong emotions seem to resonate from within your gut? Or that stress turns your stomach? The brain-gut connection, it seems, is a real thing. Here’s a look at the surprising relationship.

The Gut Does More Than Process Food

We know that the digestive tract turns food into fuel, but there’s a lot more going on in our guts. For example, the stomach maintains almost 70% of your immune system. Due to its profound effects on mood and cognition, the stomach, esophagus, small intestine, and colon are often referred to as “the second brain.”

The Second Brain

Dr. Michael Gershon, a Professor of Pathology and Cell Biology who was dubbed ‘The Father of Neurogastroenterology’, has made major discoveries about the brain-gut connection that shook the scientific community.

His 30 years of research has proven that nerve cells in our gut act the same way as our brain. This so-called ‘second brain’ actually functions independently from the brain, too.

What Is The Brain Gut Connection
What Is The Brain-Gut Connection?

How The Brain-Gut Connection Impacts Your Mental Health

When your knee gets scraped, pain signals are sent to your brain via the central nervous system. These messages need to reach your brain before you can identify the event as painful. We do not experience pain or discomfort until our brain tells us to.

The scraped knee is not the part of the body that causes us to cringe, cry, or shudder. This is a mental response. Our negative experience of the situation occurs when pain signals reach the brain – not when the knee gets scraped.

Pain medications, then, do not counter the damage done to physical tissue; they simply block certain messages from reaching the brain

The Brain Determines Our Emotional Response

Since the brain governs our response to stimuli, emotional responses to physical situations occur on a mental level. This is why some people can experience excitement or enjoyment while someone else experiences fear or dread during the exact same experience.

Your brain decides how you feel – not your body.

The Gut Helps Determine How You React To Your Surroundings

Biological processes are governed by the brain. This includes breathing, regulating blood pressure, and hormonal control. Testosterone, for example, is only produced when the brain signals the need for more of it. No internal functions take place without the brain… or so we thought. 

It turns out that the gut has as much of an impact on how we react to our environment as the brain. This is because the same neurons that govern how you perceive and react to a situation are also found in your digestive tract.

The presence of brain-like nerve cells indicates that our guts can regulate body functions just like the brain does. Hence, the brain-gut connection.

The fascinating part of this new discovery is that emotions like fear, depression, or anxiety can originate from the gut as well. A good example of this is when you get butterflies in your stomach when you feel anxious. It turns out that this is not a mental response, but one that the gut generates on its own.

Your Gut Will Tell You How To Feel

Just as our brains tell us how to feel about a particular situation (excitement or fear, pain, or pleasure). The condition of our gut will do exactly the same.

People who have more of a certain type of gut bacteria will have greater dopamine levels. This predisposes them to grasp new concepts quicker and feel good about new experiences, while those who don’t have the same type of gut bacteria are more likely to perceive the same experience as dreadful, overwhelming, and daunting.

The Gut Sends Out Its Own Messages

The brain is not merely getting signals from the gut, like with every other part of the body. The gut is generating entirely new reactions of its own.

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We know that the brain-gut connection is collaborative. The gut impacts the brain and the body in the same way as the brain itself. Our guts tell us how to react to a situation in the same way that the brain would.

You can try to overcome negative thought patterns by challenging your thoughts, but what if your gut isn’t producing the feel-good hormones like serotonin and dopamine that your brain needs to function properly?

In what ways does the gut influence the brain? And what can you do to strengthen the brain-gut connection? Let’s find out:

The Brain-Gut Connection
The Brain-Gut Connection. Journal of Neuroscience

Different Gut Bacteria Produce Different Effects On The Brain

There are between 500 and 1000 different species of bacteria living in our bodies at any given time. You might assume that we all have the same species of bacteria living in our gut, but case studies and research indicate otherwise.

Gut bacteria are responsible for more than breaking food into energy and raw materials.

How Would Our Brains Change If We Didn’t Have Gut Bacteria?

While it would be hard to study the effects of a bacteria-free gut in humans, studies done in mice have produced some persuasive results. This study showed that gut bacteria have a significant impact on personality type, brain development, and mental performance.

Lack Of Gut Bacteria Resulted In Reckless Behavior And Decreased Memory

One group of mice was bred to have no gut bacteria and was placed in a microbe-free bubble to avoid exposure to bacteria. Another group of normal mice was used as a control group to study the differences between the two. A variety of tests were performed on these mice to evaluate their mental function.

Lack Of Gut Bacteria Results In Reckless Behavior And Decreased Memory

One group of mice was bred without gut bacteria and was placed in a microbe-free bubble to avoid exposure to bacteria. Another group of normal mice was used as a control group. Scientists performed tests on these mice to evaluate the effects on their mental function. Here are two things they discovered:

1. Mice Without A Healthy Gut Bacteria Behave Recklessly

When placed in an open field, mice without gut bacteria ran for longer distances and were less concerned about taking cover. In the wild, this would inevitably increase their chances of predators eating them.

Is this nature’s way of making sure that only animals with healthy gut bacteria survive? Perhaps mice with reduced mental cognition make riskier decisions?

After all, the mice didn’t have enough brainpower to evaluate the reward (greater distance traveled) with the risk of capture. Their brains fixated on one factor and ignored other environmental factors.

In humans, risk takers are more prone to addictive behaviors and are more likely to make consequential negative decisions. Risk takers are less likely to evaluate the consequences of a decision before taking action.

2. Mice Without Healthy Gut Bacteria Experience Decreased Learning And Memory

Bacteria-free mice, along with those with normal levels of bacteria, were shown two different items at the same time: a normal ring and a checkered ring. The mice had 5 minutes to explore the new items.

Both items were removed for 20 minutes. After the 20 minute period, a new item (a cookie-cutter) was placed in the box along with a familiar item: the checkered ring.

The Brain-Gut Connection
The Brain-Gut Connection: Source

The normal mice spent more time exploring the new item while showing less interest in the previously-seen checkered ring. The bacteria-free mice, however, spent the same amount of time exploring both items. They had already forgotten about the checkered rings after only 20 minutes.

This suggests that the inability to learn from past experiences and change our actions accordingly could be linked to the gut’s affect on mental plasticity.

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Lack Of Learning Explained By Reduced Brain-Derived Neurotrophic Factor (BDNF)

The bacteria-free mice had significantly lower levels of BDNF. BDNF is a protein responsible for forming new brain cells and neural connections that facilitate learning, skill development, and memory. Mental plasticity (the ability of the brain to adapt) is directly affected by BDNF levels. Low BDNF levels lead to depression, anxiety, slower response times, and poor memory.

Do All Humans Have The Same Gut Bacteria?

Research indicates otherwise. A shocking case study found that introducing the gut bacteria from an overweight person led to rapid weight gain.

After the fecal microbiota transplant (commonly referred to as an FMT), the woman’s infection disappeared.

Brain-Regulating Hormones Are Produced In The Gut

Gut bacteria produce neurotransmitters like serotonin, GABA, norepinephrine, and dopamine. 90% of serotonin, for example, is produced in the gut. How much of each hormone is produced is heavily dependent on the type (and amount) of gut bacteria we have. Some points worth considering:

  • Serotonin is made by the microbes Streptococcus, Enterococcus, Escherichia, and Candida.
  • GABA is made by Bifidobacterium and Lactobacillus.
  •  Norepinephrine is made by Saccharomyces, Escherichia coli, and Bacillus.
  • Dopamine is made by Serratia and Bacillus.

How To Improve Your Gut Bacteria

Almost everything we do affects our gut. This is what you should do to ensure that your gut functions well:

1. Eat Less Processed Foods

Preservatives are designed to extend the shelf life of food by inhibiting microbial growth. They also inhibit the growth of healthy bacteria in the gut. We’ve known about the negative effects of processed foods for a long time, but it’s far worse when you consider the effect it has on healthy gut bacteria.

Want to learn more about a healthier alternative called The Keto Diet? Read this article.

2. Reduce Medication Where Possible

Drugs can have negative effects on the growth of beneficial gut bacteria. Bacteria thrive off wholesome foods like fruit, meat, and vegetables. Chemical compounds in medications offer no nutritional value and can even hurt healthy gut bacteria.

3. Avoid Negative Behaviors Like Smoking And Drinking Excessive Alcohol

Tobacco and alcohol are known carcinogens, but imagine the toll they take on the bacteria in your gut. Alcohol has long been used as a disinfectant, and nicotine is a plant’s natural defense against bugs and pests. Both of these things can wipe out a large portion of the gut bacteria that we need. Over time, this may lead to an imbalance of certain species of bacteria within the gut.

How To Improve Gut Health

1. Eat Foods That Are High In Fiber             

Fiber is the part of plant foods that we can’t digest. The fact that we can’t digest it does not mean that gut bacteria can’t. Foods that lack natural fiber (like processed foods and refined carbohydrates) get emptied into the bloodstream from the gut. This reduces the amount of time that healthy bacteria have to feed on good food sources.

The longer it takes for food to spoil, the less beneficial it is to the gut. Make sure to eat at least five different raw fruits and vegetables every day.

2. Eat A Variety Of Foods

Different gut bacteria thrive off of different kinds of foods. By making sure that your diet has a variety of foods, you ensure that there is enough diversity within your gut to support a healthy microbiome.

It’s easy to starve off a certain population of gut bacteria by avoiding an entire food group. Eating too much of a particular food also increases the risk of developing an imbalance of gut bacteria.

3. Exercise Regularly

Exercise increases blood flow. This allows nutrients to be delivered to the gut. It also allows for nutrients to be extracted from the gut. What good are these beneficial chemicals if they aren’t efficiently cycled through the body?

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Additionally, exercise stimulates bowel movements by moving the position of the gut. Walking and squats, for example, are great exercises for those who suffer from constipation. Much like a river, our guts need a good in-flow of nutrients and out-flow of old matter to work best.

4. Drink Enough Water

Water reigns supreme over every other beverage when it comes to supporting healthy gut bacteria. Bacteria need water to grow. This is why dehydrated foods take longer to spoil, compared to those with higher water content.

The Brain-Gut Connection: Conclusion

If you look after your gut, your gut will look after you.

Eat a variety of foods. Eat more natural fiber. Avoid things that diminish healthy bacteria. Drink enough water. These things go a long way towards ensuring that your gut works the way it’s supposed to.

Research about the brain-gut connection is clear. If you want to remain physically healthy and mentally fit, you can’t neglect your gut.

Remember to always consult your medical practitioner before making any significant lifestyle changes.

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About The Author
Saguren Redyrs
Saguren Redyrs is a personal trainer from South Africa who focuses on how small everyday changes impact overall quality of life. You can read more of his work on his site, SA Spotters

1 thought on “What Is The Brain-Gut Connection?”

  1. Hello! I just would like to give a huge thumbs up for the great info you have here on this post. I will be coming back to your blog for more soon.


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Reviewed for accuracy by Randy Withers, MA, NCC, LCMHC, LCAS. Licensed Therapist and Managing Editor of Blunt Therapy

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