What if I told you that the key to reducing many ADHD symptoms actually resides – not in the brain – but in the gut?
I know this sounds counterintuitive, because ADHD is a neurological disorder that affects both the brain and the nervous system. But, stick with me because in this article I’m going to explain in detail how the key to reducing ADHD symptoms is actually within the gut instead of the brain.
Why Disease Starts in the Gut
Many people don’t realize that just about all disease begins in the gut, or the digestive system. Approximately 80% of the body’s entire immune system is within the gut wall, along with billions of nerve cells and an extensive amount of beneficial gut microorganisms (also known as gut bacteria). This makes the gut the body’s first line of defense against external pathogens, keeping our immune system balanced and preventing chronic inflammation.
As of 2011, according to Epidemic Answers, it was estimated that 54% of American children had been diagnosed with a chronic illness, and this figure was only 15% a couple of years before that.
1 in 2 had anxiety, asthma, type 1 or type 2 diabetes, epilepsy, cystic fibrosis, heart problems, allergic conditions, learning disabilities, hyperactivity, sinus infections, ear infections and more.
1 in 5 had allergies.
1 in 6 had developmental delays.
And 1 in 68 had autism.
Why do you think this rise has occurred so rapidly? The answer is actually quite simple. It all begins in the gut.
The gut is home to trillions of microorganisms—bacteria, viruses, fungi, and more—that form a complex ecosystem, known as the gut microbiome. Research shows that the gut microbiome is responsible for more than just digestion; it also plays a key role in mental health, immune regulation, and the production of vital neurotransmitters like serotonin and dopamine. When the balance of these microorganisms is disrupted, a condition known as gut dysbiosis can occur. Gut dysbiosis has been linked to a wide range of chronic illnesses, from autoimmune disorders to neurodevelopmental conditions like ADHD.
Rapidly declining gut health is one of the major contributors to the rise in all sorts of illnesses, diseases, and conditions.
This powerful connection between gut health and chronic illness isn’t just about the body—it also has a profound impact on the brain, especially when it comes to conditions like ADHD. So, how exactly are the gut and brain linked?
Enter…..the gut-brain connection.
What Is The Gut-Brain Connection?
The gut and brain are in constant communication, working together through a sophisticated network of nerves, chemicals, and hormones. This relationship means that when your gut isn’t in good shape, it can send distress signals to the brain, affecting everything from mood to mental clarity.
In simple terms, if your gut isn’t thriving, your brain won’t be either. This two-way conversation doesn’t just impact digestion—it plays a crucial role in how we think, feel, and focus every day.
The Body’s Superhighway
Think of it this way. Have you ever felt butterflies in your stomach because you were nervous about something? Maybe it was a first date or a test or a conflict. These are the perfect examples of the gut-brain connection.
Our bodies perceive whatever we are nervous about as a stressful situation, and then our brains trigger raw emotions in the gut, resulting in nausea or that feeling of butterflies in the stomach. That’s the brain talking to the gut.
But the reverse is also true. Our guts talk to our brains as well. When the digestive system, and specifically the intestinal tract, has a higher level of bad gut bacteria than good, it’s called gut dysbiosis as mentioned earlier.
Gut dysbiosis creates inflammation that travels through the vagus nerve to the brain. Once this reaches the brain, it creates symptoms like brain fog, confusion, dizziness, poor memory, and a whole host of neuro-behavioral disorders like ADHD, anxiety, and depression.
It’s kind of like a highway, with both the gut and the brain constantly sending messages back and forth to one another.
Neurotransmitters and Gut Health: A Key to Managing ADHD
I like to think of neurotransmitters as the cars on this super highway. They are the body’s chemical messengers, carrying the messages back and forth throughout the body.
But did you know that 90-95% of the body’s serotonin and 50% of the body’s dopamine is produced in the gut. These neurotransmitters are the ones that help us manage emotions and balance mood.
In addition to serotonin and dopamine, the gut also plays a critical role in producing other key neurotransmitters. For example, research has shown that 97 organisms in the gut microbiome can produce GABA, a neurotransmitter that plays a key role in regulating mood, cognition, and sleep-wake cycles. Imbalances in GABA levels have been linked to anxiety, depression, and emotional instability—all of which can exacerbate ADHD symptoms. If the gut is not producing enough GABA, children may struggle with heightened anxiety and difficulty calming down, which can impact their focus and emotional control.
Norepinephrine, another important neurotransmitter, is critical for attention and cognitive alertness. Certain gut bacteria are known to produce norepinephrine, which means the state of gut health can directly influence how sharp and focused children with ADHD feel. Disruptions in norepinephrine production caused by gut imbalances can make it harder for children to stay focused and manage stress, further contributing to symptoms of hyperactivity or impulsivity.
Acetylcholine is well-known for its role in learning, memory, and attention—areas where children with ADHD often face challenges. While not as widely studied in relation to the gut as serotonin or dopamine, evidence suggests that gut bacteria can influence acetylcholine production. A healthy gut may help regulate acetylcholine levels, supporting better cognitive function, focus, and mental clarity.
Lastly, histamine, although commonly associated with allergic reactions, also acts as a neurotransmitter that affects wakefulness, alertness, and cognitive processes. Some gut bacteria, like those in the Lactobacillus family, produce histamine, and when there is an imbalance in gut bacteria, this can lead to an excessive production of histamine. This overload may result in symptoms like brain fog, irritability, and disturbed sleep—all of which can make managing ADHD symptoms even more difficult.
Many children with ADHD struggle to manage emotions and can often have HUGE mood swings. For these children, it’s likely that their bodies—and in particular, their guts—are not making enough of these vital neurotransmitters. Emotional dysregulation is a common symptom of ADHD, but many parents don’t realize that this emotional dysregulation often starts in the gut, where serotonin, dopamine, GABA, and other neurotransmitters are made.
The problem, then, isn’t just the emotions themselves, but the fact that the correct amounts of these crucial neurotransmitters are not being produced in the first place. By working to improve gut health, many parents of children with ADHD find that emotional and cognitive challenges begin to resolve naturally.
Now, let’s look at the frontal lobe of the brain and how gut health can affect its ability to function at its best.
The Frontal Lobe’s Role in ADHD Symptoms
The brain has many areas that are involved in gut function, but one of the key regions is the frontal lobe. This area of the brain communicates with the gut via the vagus nerve and chemical messengers that travel back and forth between the two. The frontal lobe is responsible for essential cognitive tasks such as:
- Attention
- Focus
- Executive function
- Planning
- Organizing
- Problem-solving
If you’re familiar with common ADHD symptoms, then you know that children with ADHD often struggle with ALL of these tasks. Because the frontal lobe is in the brain, many people are under the impression that the brain is what needs care, when in reality, as already mentioned, it’s also the gut that’s causing the problems.
Now, let’s look a bit more about what happens when the gut is broken down and not functioning at its best.
What is Leaky Gut?
As we’ve discussed, the gut-brain connection is essential in managing ADHD symptoms, and the health of the gut plays a vital role in this relationship. When the gut is compromised, particularly through a condition known as leaky gut, the integrity of this connection is damaged.
Leaky gut occurs when the lining of the intestinal wall becomes weakened, allowing harmful substances like undigested food particles, toxins, and bacteria to pass into the bloodstream. This breach of the gut’s natural barrier triggers an immune response and leads to inflammation, which can spread throughout the body—including to the brain.
Leaky gut is when food particles slip through the intestinal walls and head into the bloodstream. When this occurs, the body recognizes these food particles as foreign matter and then creates an immunological response.
Take a look at the graphs below for a detailed explanation of the Mucosal Barrier and Leaky Gut Progression.
The mucosal barrier is the small intestine and the lining of the small intestine. It connects the stomach and the large intestine and runs about 22 feet long. When it is functioning well, it absorbs about ninety percent of our nutrients from the food we eat and transports water, nutrients, and vitamins into our cells.
When it isn’t functioning well, it can actually increase toxicity in the body.
As you can see on the image above, the musical barrier has a single layer of cells called enterocytes that line the barrier. These are held together by tight junctions whose main function is to keep particles from getting through. You can also see microvilli on this image. These microvilli absorb the nutrients that keep us healthy.
Basically, the mucosal barrier’s job is to keep the bad guys (like bacteria and viruses) out and let the good guy (nutrients, for example) in. It takes all those food macronutrients (like carbs, fats, protein, etc) that we eat and digests and converts them into micronutrients, so they can be absorbed by these villi, which then deliver them to the bloodstream and into our cells. Nothing larger than this micronutrient size should be able to get through.
There is also another defense system here, in addition to this physical barrier. We also have a chemical barrier created in the small intestine called secretory I.G.A. or sigA. SigA exists to protect against things that should not come into the system. Both the physical barrier and the chemical barrier are there to make sure that nothing gets in the bloodstream that shouldn’t be there.
Imagine what would happen if these defense systems are not functioning properly.
It would compromise nutrient absorption and also allow nasty toxins and bacteria to leak into our bloodstream.
Or, in other words, it would create something called Leaky Gut. Take a look at the image below for more information about the Leaky Gut Progression.
At the top of this image, you can see various drugs, toxins, pathogens, etc that should not get into the bloodstream.
Unfortunately, if these are there on a consistent basis, and if they continue to leak into the bloodstream because of Leaky Gut, it can trigger inflammation, or it can damage the mucosal barrier even further.
The more onslaught it receives, the larger the holes, and the larger the molecules can leak through into your system.
Normally when you don’t have holes in the lining of the gut, our gut breaks down the food that we eat into micronutrient size particles, and those particles go through the lining of the gut into our cells to give us the nutrients we need so we can function optimally.
BUT when leaky gut is present, when we eat food (even the healthiest food), before the gut has had a chance to break it down, it can go through the holes in the gut into our bloodstream.
The way the body is designed is that when something foreign goes in our blood stream, it recognizes it as a foreign object and turns on an immune response.
If that large molecule is in fact a large food macronutrient or protein, then your immune system might start sending signals to create an immune response and start creating antibodies and start attacking it.
The body has a great memory so anytime you eat that again, your immune system sees it as dangerous and attacks it, which causes more inflammation and continues to further break down the lining of the gut.
This results in food intolerances, and these food intolerances continue to wreak havoc on the gut until they are removed.
It is a vicious cycle. Something started the leaky gut, then the leaky gut causes food intolerances, and the food intolerances continue to cause leaky gut.
So in order to heal the gut, you must remove these foods or they will continue to break down the lining of the gut.
To add fuel to the fire, all of these invaders that are causing this inflammation then cause the villi to shrink and become blunted and flattened out. This can result in nutrient deficiency or vitamin deficiency because so much of the minerals and vital nutrients can’t be absorbed and even the healthiest foods aren’t able to be absorbed.
Signs of a Compromised Gut-Brain Connection
Now that you understand what leaky gut is and how it affects the body, let’s look at some potential signs or symptoms of leaky gut.
When the gut is broken down and leaky gut occurs, the result is often a variety of symptoms that can affect the whole body.
Take a look at the graph below for some common symptoms of leaky gut. Keep in mind, it’s possible to have leaky gut even if you only have one or a couple of symptoms. You don’t need to have all of the symptoms.
Along with the symptoms of a leaky gut (shown in the graph above), another way to determine if the gut is broken down is through functional lab testing.
My favorite tests used to identify leaky gut include the following:
- A Wheat Zoomer with Leaky Gut panel which looks at leaky gut (intestinal permeability), gluten and wheat sensitivity, celiac disease, and gluten-mediated autoimmunity. A wheat sensitivity can severely compromise the health of your gut as it can inflame the gut lining.(Our favorite is through Vibrant Wellness.)
- A Food Sensitivity Test looks at which foods in particular create those immune responses in the body. (Our favorite is through Vibrant Wellness.)
- The Organic Acid Test (or OATS) looks at over 65 important markers in the whole body and how it is functioning.
- A Gut Stool Test looks for parasites, bacteria, yeast overgrowth, as well as inflammation, digestion, and metabolic functions of the gut.
For more information about my favorite functional lab tests, please watch this short training video.
Now that you understand leaky gut and the importance of the gut-brain connection, you might be wondering what actually causes it to occur in the first place.
What Causes a Breakdown in the Gut-Brain Connection
There are actually a variety of things that could cause the gut-brain connection to break down. Some of the most common causes that I see in the children I work with include:
❌ Frequent antibiotic use
❌ Parasites
❌ Toxic exposure
❌ Medication
❌ Food sensitivities
❌ Gluten
I have countless families come to me for guidance with their child’s ADHD symptoms, and when I ask if their child had been on lots of antibiotics when they were younger, a massive percentage of the children had.
Most antibiotics work by killing bacteria or preventing it from growing. Unfortunately, most antibiotics can’t distinguish between good and bad bacteria. That means they can wreak havoc on the gut’s healthy bacteria. Many people actually suffer lasting changes to their gut flora as a result of taking antibiotics.
How Gluten Affects The Gut-Brain Connection
Another common cause of the breakdown of the gut-brain connection, along with antibiotics, is gluten.
Gluten is a protein found in wheat, barley, and rye. I recommend that all families of kids with ADHD remove gluten completely from their diets. There are 3 primary reasons for this.
First of all, gluten leads to a breakdown of the gut in EVERYONE!
Many people mistakenly assume gluten is only bad for those who have Celiac Disease. But that’s not the case! Gluten is a highly inflammatory substance and is difficult to digest for EVERYONE!
Research shows that it triggers increased intestinal permeability (which is basically a breakdown of the gut lining) in EVERYONE who eats it.
While this leaky gut condition is only temporary for most individuals to begin with, once they cross the threshold where their immune system starts to produce antibodies against gluten, they are then considered to have a gluten sensitivity.
A second reason I recommend families avoid gluten is because gluten has been linked to multiple diseases and disorders, including ADHD and others.
Finally, the third reason is because gluten has the potential to create an opiate-like effect in some people.
Yes, you read that right! Opioids, like morphine!
When the enzymes in the gut are not able to fully break down gluten, a protein is created that is similar in structure to morphine. These proteins bind to opiate receptors in the brain and can create opiate-like effects.
My son used to have huge meltdowns, where he behaved like a completely different person. It was like he couldn’t control himself at all.
And the truth is, he couldn’t. Just like an addict, he was controlled by something else…the opiate receptors in his brain!
When we removed gluten from my son’s diet, he experienced a 90% improvement in all of his ADHD symptoms. For us, removing gluten was the game-changer!
Treating the Underlying Stressor of ADHD Instead of Symptoms Alone
As you’ve learned in this article, a person’s gut health is quite literally connected to everything that occurs in the body. This means that if we are able to improve gut function, then we are able to target not just symptoms but underlying stressors as well.
The gut and brain are constantly sending messages back and forth on that superhighway we discussed earlier. When medication is prescribed for ADHD, it’s often to treat the symptoms in the brain alone. But that medication does absolutely nothing about whatever might be going on in the gut.
Think about SSRIs, Selective Serotonin Reuptake Inhibitors, for example. These medications are often prescribed to people with depression and anxiety. Serotonin is one of the neurotransmitters that enables brain cells to communicate with one another. It helps with mood stabilization and makes people feel happy. SSRIs make more serotonin accessible in the brain by blocking its reabsorption. In essence, what SSRIs do is help the patient’s body better manage the serotonin it currently has. They DON’T actually create more serotonin in the body.
What I’m advocating in this article is that there is a better approach. Instead of treating the symptom (i.e. the fact that serotonin isn’t being managed correctly), figure out why the body isn’t producing enough serotonin in the first place. Then fix this issue so the body begins to produce the right amount of serotonin on its own.
It’s like a fire. When a house fire breaks out and the emergency responders arrive on scene, they don’t aim their hoses at the smoke. They aim them at the fire. They know that if they get the fire out, the smoke will eventually dissipate.
It’s the same way with our health. If we aim for the fire (in our case, the underlying stressor), the smoke (or symptoms) will eventually dissipate. But if all we do is flood the smoke with water, we’re never actually even touching the problem below. Let’s stop shooting water at smoke and start getting to the underlying issues!
Focus on the underlying stressor, not just the symptom on the surface. To focus on the brain and not the gut is counterproductive. It doesn’t make sense, because the brain and the gut are connected to one another, and they’re constantly communicating.
Here are some practical tips to begin supporting the gut-brain connection.
Practical Ways to Support the Gut-Brain Connection
What can you do if you suspect leaky gut or a weakened gut-brain connection could be exacerbating your child’s ADHD symptoms? Are there any at-home strategies that can improve the gut-brain connection and support leaky gut?
Absolutely! I actually have a free Leaky Gut Guide, that provides you with steps to support leaky gut, as well as 25 gut-healing recipes!
<<Grab Your Leaky Gut Guide Here>>
Here are some additional ways to support the gut-brain connection:
1 – Cut out highly inflammatory foods.
The biggest offenders in most people are gluten, dairy, soy, artificial flavors/colors, excessive amounts of sugar, and any foods that pop up on a food sensitivity test.
I’ve written and spoken quite a bit about this topic, so check out these links to learn more:
The ADHD Diet, Part 1 (podcast episode)
The ADHD Diet, Part 2 (podcast episode)
Food Sensitivities & ADHD (article)
2 – Eat more nutrient-dense foods (like whole fruits and veggies, grass fed and wild caught protein sources, and healthy fats).
These foods will help rebuild gut health and strengthen that gut-brain connection.
3 – Use targeted supplementation based on functional lab test results to support gut healing.
Many people use a “pin-the-tail-on-the-donkey” method when supplementing. They learn about a supplement that has helped others and hope it will help their own child as well. They give it a try without testing first.
And though this does occasionally help, ideally we want to supplement based on the results of functional lab tests, as this is a much more targeted approach.
4 – Eat prebiotic/probiotic foods and/or take supplements.
Just about everyone can benefit from prebiotics and probiotics. Both support gut health, but they serve different roles:
Probiotics are live beneficial bacteria that naturally occur in your gut. They help maintain a healthy balance of gut bacteria, support digestion, boost the immune system, and reduce inflammation. Probiotics can be found in fermented foods like yogurt, kefir, sauerkraut, and certain supplements.
Prebiotics, on the other hand, are non-digestible fibers that act as food for the probiotics. They stimulate the growth and activity of beneficial bacteria in the gut. Prebiotics are found in foods like onions, garlic, bananas, and whole grains.
In short, probiotics are the good bacteria, and prebiotics are the food that helps those bacteria thrive. When taken or eaten together, they can enhance gut health even further.
5 – Drink plenty of spring water.
This will aid your body in detoxification and help flush out any toxins, as well as hydrate all body systems.
6 – Prioritize sleep.
Poor sleep can affect the gut microbiome and create inflammation in the body. By prioritizing sleep, we are also prioritizing gut health!
Next Steps in Improving the Gut-Brain Connection
While the science behind the gut-brain connection is exciting, trying to figure out your microbiome health on your own can be overwhelming. That’s where working with a skilled functional health practitioner can make a real difference.
As a health and nutrition practitioner, I have the knowledge and access to advanced functional testing tools that allow me to thoroughly explore the unique makeup of your child’s gut microbiome, providing a clear picture of what’s happening in their gut.
With this detailed information, I can craft a personalized plan to correct imbalances and address any deficiencies. This often includes recommendations for specific foods, supplements, and lifestyle changes, all tailored to meet your child’s individual needs. Unlike generalized approaches, these custom strategies aim to tackle the underlying stressors of your child’s body.
Many conventional healthcare providers may not have the resources or expertise to offer this level of gut health analysis or personalized solutions.
By working with someone like me and my team here at the ADHD Thrive Institute, you can access transformative solutions that address the underlying stressors of your concerns, not just the symptoms.
Interested in learning more? Let’s see if we’re a good fit.
Start your journey here.
References:
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