October 5, 2021

It is generally known that the brain can trigger feelings in the gut like a rumbling stomach, instant urge to pee, or nausea when tensed or nervous. However, new research indicates that activities in the gut can equally trigger mental responses like anxiety or depression. This phenomenon is tagged as the gut-brain connection.

In this article, we will take a close look at the gut-brain connection, discussing what it is, the impacts on our mental and general health, as well as how to improve the connection to foster our overall quality of life.  Mind you; it might seem like you’re in a biology class; however, it is an interesting one.

Let’s get started already!

What is the Gut-Brain Connection?

The Gut-brain connection is a compound word, and splitting it might be a worthwhile approach toward deciphering its meaning.

The gut (Gastrointestinal tract) is the long tube that starts from the mouth and ends up in the anus. It includes organs like the oesophagus, stomach, large intestine, small intestine, gallbladder, pancreas, liver, colon, and rectum. The gut is responsible for the digestion of ingested food, absorption of nutrients and excretion of waste.

The brain, as you know, is the complex organ located in the head that controls all mental and bodily functions.

Therefore, the gut-brain connection describes a phenomenon that the activities and interaction of ingested food and gut microbes can send signals to the brain and alter bodily and mental functions like metabolism, mood, quality of sleep, anxiety, depression, and more.

In other words, this phenomenon tells us that food and our gut health has a way of affecting our overall quality of life, including our moods.

So, how is the gut connected to the brain?

There are three connections between the gut and the brain. Namely:

  • Through the Nervous System
  • Via Neurotransmitters
  • Gut Microbes

Through the Nervous System

The nervous system refers to the body’s command centre. It consists of the brain, spinal cord, and a network of special cells called neurons or “nerve cells” that send messages from the brain to all parts of the body, controlling thoughts, bodily actions, and responses.

There are two sections of the nervous system- the central nervous system and the peripheral nervous system.

The gut-brain connection stems from the peripheral nervous system; specifically, a part of the peripheral nervous system called the Enteric Nervous System (ENS) located in the gut. In fact, 100billion nerve cells are responsible for sending messages to all body parts, and about 500million of these nerve cells connect the brain and the gut. The biggest of these nerves cells is the vagus nerve.

The primary aim of nerve cells that directly connects the gut to the brain is to send signals to and from the brain on activities happening in the gut. These signals could end up becoming “feelings like satiety, stress, etc.,” and “bodily response like constipation, gastrointestinal responses.” (3, 4).

Overall, the gut-brain link via the nervous system is quite simple- through the ENS and a network of special cells called neurons located in the gut that directly connects the gut to the brain.


While nerve cells/neurons spread around your body, these cells can’t send signals to target cells in the muscles, glands or other nerves cells by themselves. They rely on a special chemical called neurotransmitters.

Neurotransmitters work similarly to hormones. For example, the neurotransmitter dopamine is responsible for the brain’s reward system and helps you “feel good” or “pleasure” after an exciting activity, maybe satisfying a craving. 

Several neurotransmitters, including those that control mood, fear, anxiety, and cognition, like gamma-aminobutyric acid (GABA), dopamine, serotonin, and melatonin, are produced in the gut. Imperatively, if your gut isn’t healthy enough to make these chemicals in their proper amount, it will alter their normal operation, distorting your mood, anxiety, fear, cognition, and more.  

Gut Microbes

Trillions of microbe/microorganisms live in the gut and produce chemicals, including neurotransmitters and hormones that affect numerous bodily and mental functions.

One of such chemicals includes short-chain fatty acids (SCFA) like acetate, propionate, and butyrate that, alongside keeping the gut environment stable, contribute to brain-related functions like appetite, mood, blood-brain barrier, and the immune system.

Many more chemicals produced by the gut also affect deeper physical wellness like gene production, the immune system, and inflammation (the root cause of many diseases, including high cholesterol, dementia, depression, etc.) (5)

In summary, the key takeaway behind all of these biology lessons  is that your gut microbes/bacteria is responsible for numerous functions, including housing nerve cells, producing neurotransmitters, hormone and special chemicals that are directly involved in our mental and physical health

Impacts Of The Gut-Brain Connection

Though the gut-brain connection is the same for everyone, the effect isn’t. For example, we can’t say eating this or that food will make you feel depressed or increase your anxiety. However, your gut health, including your food sensitivities, is the primary determinant of the effects of your gut-brain connection.


If you are following this article keenly, I’m sure you could guess the gut-brain connection and its impact on anxiety correctly.

Well, repeating it wouldn’t be a crime. So, let’s do just that!

The impact of the gut-brain link on anxiety stems from all three connections- the nervous system, neurotransmitters and gut microbes. And here is how it works.

First, neurotransmitters critical for mood, motivation, concentration, and anxiety, like dopamine, serotonin, and melatonin, are produced in the gut. Proactive/sensitive guts can alter the production of these neurotransmitters when you eat foods your digestive system can handle adequately. As such, you can find yourself tired, unmotivated, unimpressed and anxious after having those meals.

The critical problem is that the foods themselves could be healthy, and many doctors could just tell you to add them to your list of sensitive foods without dealing with the root cause- an unhealthy gut. Even worse, the list keeps getting longer.

Furthermore, an unhealthy or proactive gut can influence inflammatory responses and ultimately contribute to alterations in the nervous system via the vagus nerve. Thus, affecting signals which contribute to mood and causing depression and other anxiety-related disorders (7).


As stated earlier, alterations in inflammatory responses via the vagus nerve because of a proactive gut link to negative effects, including depression and anxiety (8).

That is because gut bacteria produce hundreds of neurochemicals the brain uses to regulate psychological and mental processes like mood, learning, and memory. For example, almost 95 per cent of the body’s supply of serotonin comes from gut bacteria.

Adequate production of serotonin allows your body to regulate mood, happiness, and anxiety. Similarly, low serotonin levels (from an unhealthy gut) will lead to depression.

Attention Deficit Hyperactivity Disorder (ADHD)

The effects of the gut-brain connection exceed matters like depression and anxiety to serious health concerns like autism and ADHD. That is because a malfunctioning gut will not only cause digestive issues but allow brain-damaging toxins to be absorbed in the blood.

In fact, various studies on patients with ADHD identified bacteria groups of the gut microbiome as possibly playing a role in neurological and psychiatric disorders like ADHD.

Though deviations from the usual microbial compositions in the gut, especially from an unhealthy gut, does not cause ADHD directly. Nevertheless, the changes alter brain structure and function, which, in turn, links to ADHD and other neurodevelopmental disorders (9).

How To Improve The Gut-Brain Connection

Gut Healing

One thing we could deduce from this article up to this section is that all the negative impacts of the gut-brain connection are caused by an unhealthy gut. So, the journey towards fostering the gut-brain link is straightforward (unlike the old movie; a journey to the mysterious island ) - get your gut healthy again.

Think of it this way; if you want to make a road trip in a car, the foremost way to improve your journey is to make sure the vehicle is fully functional by servicing and repairing defective parts if possible. That is because every other assortment and exciting adventure you may have prepared to adorn your journey will be futile if the car breaks down mid the trip.

The above concept applies very significantly to the gut-brain connection. If you are looking to improve the transmission of signals from your gut to your brain and possibly get the best mental and physical state at all times, you make sure to get your gut fully functional. Else, every other food or lifestyle change will seem like “pimping” a car with a defective engine.

You can start your gut healing journey by following practical steps in my free gut-healing mini-guide. You can also proceed to my gut healing program, where you can follow a more comprehensive approach to understanding your unique digestive and immune systems and how to improve your mood, energy levels, and overall health.

Add Probiotics to Your Diet

Probiotic-rich foods contain live, healthy bacteria that improve your gut health. By eating more probiotics like kefir, sauerkraut, pickles, miso, kimchi, yoghurt, or kombucha, you will be adding more bacteria to your gut that produces mood-boosting neurotransmitters, aids digestion and metabolism, as well as lower the risk of inflammation.

Yet, it is worth mentioning that the effects and benefits of probiotic foods decline with cooking or storing at high temperatures.

Prebiotic Foods

Unlike probiotic foods, prebiotic food does not contain live, healthy bacteria that add to your gut microbiome. However, prebiotics contains indigestible fibres that ferment in the GI tract and then converted into digestion-promoting compounds.

Prebiotic-rich foods include onion, garlic, legumes, artichoke, asparagus, oats, and cabbages.

High-Fiber Foods

High-fibre foods like grains, whole nuts, fruits, and vegetables contain prebiotic fibres that ferment in the gut to produce healthy compounds beneficial to the gut microbiome and digestion.  


 Exercising offers many benefits, including promoting digestion by increasing the diversity of gut bacteria and fostering digestion. More so, exercise helps relieve stress and other inflammation markers responsible for altering gut-brain neurological signals and causing depression, ADHD, anxiety, and distorting overall health.

Final Words

In summary, the gut-brain connection is an exciting and fact-based phenomenon that describes how activities in the gut can alter responses and signals to the brain, which in turn affects our mental and physical health.

However, your gut health is the key player in influencing the effects of the gut-brain connection.

There are practical ways to get the best out of the gut-brain connection with an overall aim of better mental and physical health. Yet, the most salient among these methods is to reboot your gut activities and get your gut to its full functionality.

You can start the reboot with my free gut-healing guide or opt for my gut healing program for a comprehensive approach. 

The steps in the free guide and paid program are those I took some years ago when I had gut issues after having my first child. I have improved the overall approach in the gut-healing program to accommodate several gut conditions and have gotten mind-blowing results from my clients worldwide.

About the author 

Aayah Khalaf

A health coach and detox specialist, CEO and founder of Bee Nourished a health and weight-loss initiative. I help women and mothers achieve their health and weight-loss goals with life changing programs that are uniquely yours.

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