The Gut-Brain Connection Secrets Revealed

The Gut-Brain Connection Secrets Revealed

The Gut-Brain Connection Secrets Revealed

Have you ever had a “gut feeling” about something? Or felt “butterflies in your stomach” when you were nervous? Well, it turns out there’s a lot of truth to these sayings. 

Your gut and your brain are more connected than you might think. And this relationship, known as the gut-brain connection or brain-gut connection, can have a significant impact on your overall health and well-being.

As we navigate through our 40s, 50s, and beyond, we might start noticing changes in our bodies and minds. 

  • Maybe you’re not bouncing back from stress as quickly as you used to. 
  • Maybe you’re noticing more anxiety or mental distress than before. 
  • Maybe you’re experiencing new gastrointestinal problems or digestive disorders

You are likely juggling work, family responsibilities, and personal goals—all while trying to maintain your physical health and mental health. It’s a lot to handle! 

But understanding the gut-brain axis can help you make sense of these mystery symptoms and health challenges so you can find new ways to feel your best.

What Is the Gut-Brain Axis?

In simple terms, the gut-brain axis is the communication network between your digestive system and your central nervous system (which includes that big brain of yours!). 

Imagine your gut and brain as two cities connected by a busy, two-way highway—in fact, let’s call it Highway GBA (Gut-Brain Axis). 

The gut constantly sends resources like neurotransmitters and hormones to the brain, while the brain sends signals back to regulate digestion and immune function. When the highway is running smoothly, you feel great. Things are moving properly, there’s flow and efficiency.

When there’s a traffic jam caused by inflammation or stress, it causes all sorts of chaos.

This “blockage” in the communication system can lead to mood swings, brain fog, and digestive issues, just as examples. 

The “Second Brain” in Your Gut

You’ve probably heard you have a “second brain” in your gut. It’s actually called the enteric nervous system (ENS), and it’s made up of millions of nerve cells that line your gastrointestinal tract—from your esophagus to your rectum. The ENS is so complex and well-resourced that it can function mostly independently, even if disconnected from the brain! Pretty wild, right?

The ENS plays a crucial role in controlling digestion, but it also communicates with your central nervous system through a network of nerves, including the vagus nerve. This means that what happens in your gut can directly affect what happens in your brain and vice versa.

For example, have you ever felt nauseous or had stomach pain when you were really stressed out? That’s your brain sending signals to your gut in response to emotional distress. 

On the flip side, when your gut is unhappy (maybe you ate something that didn’t agree with you), it can send signals to your brain that make you feel anxious, irritable, or depressed(2).

The Microbiome’s Multifaceted Influence on Your Health

Now that you know just how connected your gut and brain are, it’s time to bring in the microbiome.

The microbiome is the complex ecosystem inside the body containingthe trillions of bacteria, fungi, and other microbes that live in your digestive tract. 

These tiny organisms, also known as gut microbes or gut microbiota, are essential for breaking down food, absorbing nutrients, and keeping harmful invaders in check. But they also play a big role in your other aspects of your overall health.

Microbiome Influence on Your Mental Health

Research has shown that the composition of the gut microbiome plays a role in mental health. It can influence your mood, behavior, and even your risk of developing certain mental health conditions like depression and anxiety

That’s because the gut is responsible for many of the brain’s most critical neurotransmitters and chemical messengers that influence brain function, mood, and mental health.

For instance:

  • Around 90-95% of the body’s serotonin is produced in the gut, not the brain. Serotonin is a key neurotransmitter involved in regulating mood, sleep, appetite, and cognitive function. Imbalances in gut serotonin levels have been linked to conditions like depression, anxiety, and autism spectrum disorder(3)
  • A 2018 study revealed that 97 gut microbiome organisms could produce GABA (Gamma-Aminobutyric Acid), which helps regulate mood, cognition, and sleep-wake cycles. Imbalances in gut GABA levels have been associated with conditions like anxiety, depression, and epilepsy(4).
  • About half of our daily dopamine is made in the gut. Dopamine is our “happy hormone” and plays a crucial role in regulating mood, motivation, and motor control. Imbalances in gut dopamine levels have been linked to conditions like Parkinson’s disease, ADHD, and schizophrenia(5).
  • Acetylcholine, a neurotransmitter that supports focus, productivity, and mental clarity, has been found to be produced by multiple bacteria, including Lactobacillus plantarum and Bacillus subtilis. Proper acetylcholine levels contribute to enhanced cognitive function and task performance(6).

Microbiome Influence on Neuroinflammation

The bacteria living in our gut also include processes like neuroinflammation and neurodegeneration.

Neuroinflammation refers to the activation of the immune cells in the brain, leading to the release of inflammatory molecules

Research shows that imbalances in the gut microbiome can promote this neuroinflammation, which has been linked to the development and worsening of neurodegenerative diseases such as Alzheimer’s, Parkinson’s, and multiple sclerosis.

Certain gut bacteria and the substances they produce can also directly impact the health and functioning of the brain’s neurons (nerve cells). For example, short-chain fatty acids made by “good” gut microbes can help protect neurons, encourage the growth of new neurons, and even delay the onset of neurodegenerative conditions.

Protecting the health of our neurons is vital, as they enable us to learn new skills, form memories, and maintain sharp cognitive function. For instance, having healthy neurons allows us to more easily learn a new language, grasp new skills that could advance our careers, or pick up a new hobby like playing a musical instrument.

Protecting the health of our neurons is vital, as they enable us to learn new skills, form memories, and maintain sharp cognitive function. For example, having healthy neurons allows us to more easily learn a new language, grasp new skills that could advance our careers, or pick up a new hobby like playing a musical instrument. When our neurons are well-supported, we can more readily adapt, grow, and stay mentally agile, even as the demands on our time and attention increase.

When the delicate microbiome balance is compromised, the quality and quantity of these crucial neurotransmitters and compounds are affected. This is why prioritizing the gut in seeking to prevent or resolve inflammation throughout the body—including brain—is so critical.

Microbiome Influence on Your Hormones

As we age, our bodies go through a lot of changes—and our hormones are no exception. In fact, wild hormone swings are one of the signs of MADS (Middle Age Deficiency Syndrome) that my clients are looking to address!

For instance, in women, menopause can bring a host of symptoms like mood swings, sleep disturbances, and hot flashes as estrogen levels decline. 

The loss of estrogen during menopause has widespread effects on the body, contributing to issues like bone loss, cardiovascular changes, and genitourinary symptoms.

For men, andropause (the gradual decline in testosterone levels) can lead to fatigue, muscle loss, decreased libido, and sexual dysfunction. Testosterone is crucial for maintaining muscle mass, bone density, and overall energy levels in men as they age.

These hormonal shifts can significantly impact our overall health and quality of life. But research indicates that the key to managing these age-related hormonal changes may lie within the gut – more specifically, in the delicate balance of our gut microbiome.

The trillions of microbes that reside in our digestive tract play a critical role in the production, regulation, and metabolism of our hormones. For example, certain gut bacteria can directly synthesize hormones like estrogen, testosterone, and cortisol(7,8). Other microbes can influence hormone levels by breaking down or activating hormone precursors, which are the molecules hormones are made from.

Tryptophan is an example of an important hormone precursor that is influenced by the gut microbiome. Tryptophan is an amino acid that can be converted into the neurotransmitter serotonin, which is a precursor to the hormone melatonin. Serotonin and melatonin play crucial roles in regulating mood, sleep, and circadian rhythms – all of which can be disrupted during hormonal changes like menopause and andropause.

When the gut microbiome is disrupted, whether due to factors like diet, stress, or medications, it can disrupt the careful hormonal balance that our bodies rely on. This microbiome imbalance has been linked to a range of hormone-related issues, including menopausal symptoms in women to androgen deficiency in men.

By supporting a healthy, diverse gut microbiome through diet, lifestyle, and targeted protocols, it may be possible to help manage the hormonal changes that come with aging. This holistic approach to supporting the gut-hormone axis could offer a natural way to mitigate uncomfortable symptoms and maintain vitality as we move through the different stages of adulthood.

Microbiome Influence on Your Stress Response

All of these hormonal shifts can have a big impact on the gut-brain axis. Stress, in particular, is a major disruptor of the delicate balance between your digestive system and your brain

When you’re under stress, your body releases a cascade of hormones like cortisol and adrenaline that can wreak havoc on your gut. These stress hormones can increase inflammation, alter the composition of the gut microbiome, and even make your gut more permeable (a condition known as “leaky gut“). This allows toxins, undigested food particles, and harmful bacteria to escape the digestive system and enter the bloodstream, triggering an immune response and promoting systemic inflammation).

Recent research has shed light on the intricate relationship between the gut-brain connection and inflammation. When the gut barrier becomes compromised, it can lead to a condition called “leaky gut.” 

Interestingly, a similar process can occur in the brain. The blood-brain barrier, which normally protects the brain from harmful substances, can also become leaky due to inflammation. This “leaky brain” syndrome allows toxins and inflammatory molecules to enter the brain, contributing to neuroinflammation and various neurological disorders.

The connection between leaky gut and leaky brain is so strong that some experts refer to them as “mirror images” of each other. In fact, studies have shown that when the gut barrier is compromised, it can lead to increased blood-brain barrier permeability within minutes to hours(10). This highlights the lightning-fast communication between the gut and the brain and underscores the importance of maintaining a healthy gut microbiome for optimal brain health.

Over time, chronic stress can lead to a vicious cycle of gut dysfunction and mental health issues. You might start experiencing digestive issues like bloating, constipation, or diarrhea, which can make you feel even more stressed and anxious. Or you might find that your mood and cognitive function are taking a hit, making it harder to cope with the demands of daily life(2).

Research also indicates that chronic stress leads to accelerated aging. Chronic stress can speed up the shortening of telomeres, the protective caps on the ends of our chromosomes. This telomere shortening is considered a hallmark of cellular aging and has been linked to a higher risk of age-related diseases. Furthermore, stress-induced inflammation can damage DNA and cellular structures, leading to impaired organ function and an earlier onset of age-related conditions.

When we experience stress, it can disrupt the delicate balance of the gut microbiome. This can lead to changes in the production of those crucial neurotransmitters in the gut. These neurotransmitter imbalances can then affect the brain, altering our perception of stress and our physical response to it.

Conversely, chronic stress can also negatively impact the diversity and composition of the gut microbiome. This creates a vicious cycle, where the gut-brain disruption perpetuates the stress response.

This intricate interplay between the gut and the brain has important consequences for our ability to adapt to and cope with stress. Since stress management is so crucial for overall health and well-being, the gut-brain axis plays a key role in this process.

Practical Tips for Supporting Your Gut-Brain Connection

The good news is that there are plenty of ways to support your gut-brain connection and promote overall health and well-being. 

Here are a few tips:

  1. Eat a diverse, fiber-rich diet. Focus on whole, plant-based foods like fruits, vegetables, whole grains, and legumes. These foods provide the fiber and nutrients your gut bacteria need to thrive.


  2. Limit processed and high-sugar foods. These foods can disrupt the balance of your microbiome and contribute to inflammation and gut dysfunction. You can make simple swaps to eliminate inflammatory foods and choose healthier versions without losing flavor or satiety.


  3. Consider probiotic supplements and prebiotic foods. Probiotics are beneficial live bacteria that can help restore balance to your microbiome. You can get probiotics through foods such as yogurt (look for live, active cultures), kefir, sauerkraut, kimchi, miso, tempeh, kombucha, and pickled vegetables—or via supplements like CT-Biotic.

Prebiotics are non-digestible fibers that feed your gut bacteria and promote their growth. Certain foods, such as garlic, onions, bananas, oats, apples, and 

asparagus, have natural prebiotics, or you can consume prebiotic fiber supplements, such as PaleoFiber RS

  1. Manage stress through relaxation techniques like meditation, deep breathing, or yoga. Regular exercise is also a great way to reduce stress and support gut health.
  1. Create an evening winddown routine. Most of us don’t relax long or deep enough before going to bed, leading to shallow, disrupted sleep. Practicing self-care rituals, such as a warm evening bath, turning off electronic devices and blue light sources 2-3 hours before bed, and gratitude journaling, allows your body to wind down after a day of activity and prepare for sleep.
  1. Stay hydrated. Drinking plenty of water helps keep your digestive system moving, prevents constipation, and keeps adequate hydration flowing throughout the body, including the brain.
  1. Stimulate your vagus nerve. Our sympathetic nervous switch flips on when we’re in chronic stress mode. This is our “fight or flight” instinct designed for action. Using vagus nerve stimulation techniques helps trigger the opposite state, the parasympathetic nervous system response, known as our “rest and digest” state, which triggers healing.
  1. Get enough sleep. Poor sleep can disrupt your gut microbiome and contribute to inflammation and mental health problems. Aim for 7-9 hours of quality sleep per night.

Unlock the Power of Personalized Gut Health Solutions

While the research on the gut-brain connection is compelling, navigating the complexities of microbiome health on your own can be overwhelming. That’s where working with a qualified functional health practitioner can be invaluable.

Functional medicine providers (like me!) have the expertise and advanced testing capabilities to investigate the unique makeup of your gut microbiome. Through specialized lab tests, we can analyze the diversity, balance, and function of the trillions of microbes living in your digestive tract. This gut microbiome testing provides a detailed snapshot of the microbial ecosystem within your body.

Armed with this personalized data, we can then develop a targeted plan to address any imbalances or deficiencies. This may involve recommendations for specific foods, supplements, lifestyle shifts, or other holistic interventions uniquely tailored to your individual needs. Unlike a one-size-fits-all approach, customized gut-healing protocols are designed to get to the root cause of your symptoms.

Conventional healthcare providers often lack the resources and experience to conduct this level of gut analysis or design completely custom solutions. How do I know? I worked in the traditional Western medicine system for decades!

Working with a functional medicine expert can unlock access to transformative gut-based solutions for those looking to solve problems at the root—not just address symptoms. 

If this sounds ideal to you, let’s see if we’re a good match.

Take your first step here.

By understanding the link between our gut and our brain, we can make informed choices about our diet, lifestyle, and stress management practices. So go ahead and trust your gut—it might just be trying to tell you something important!

Take Good Care,



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  4. Braga, J.D., Thongngam, M. & Kumrungsee, T. Gamma-aminobutyric acid as a potential postbiotic mediator in the gut–brain axis. npj Sci Food 8, 16 (2024).

  5. Strandwitz P, Kim KH, Terekhova D, Liu JK, Sharma A, Levering J, McDonald D, Dietrich D, Ramadhar TR, Lekbua A, Mroue N, Liston C, Stewart EJ, Dubin MJ, Zengler K, Knight R, Gilbert JA, Clardy J, Lewis K. GABA-modulating bacteria of the human gut microbiota. Nat Microbiol. 2019 Mar;4(3):396-403. doi: 10.1038/s41564-018-0307-3. Epub 2018 Dec 10. PMID: 30531975; PMCID: PMC6384127.

  6. Chen Y, Xu J, Chen Y. Regulation of Neurotransmitters by the Gut Microbiota and Effects on Cognition in Neurological Disorders. Nutrients. 2021 Jun 19;13(6):2099. doi: 10.3390/nu13062099. PMID: 34205336; PMCID: PMC8234057.

  7. Auborn, K. J., Fan, S., Rosen, E. M., Goodwin, L., Chandraskaren, A., Williams, D. E., … & Chen, D. (2003). Indole-3-carbinol is a negative regulator of estrogen. The Journal of nutrition, 133(7), 2470S-2475S.

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