Cognitive Health and Leaky Gut: The Frightening Connection

Improving cognitive healthWhether you are sitting in class, trying to estimate your budget, or reminiscing with friends, you are using a good amount of brainpower. You use your mind constantly, and your well-being depends on nourishing it properly. Habits play a big role. One ice cream cone won’t cause cognitive decline, but if your lifestyle involves almost daily sugar, fast foods, contact with toxins, or excessive stress, it could do just that. Most people don’t realize the important role gut health plays in protecting the mind. Research shows that cognitive health can diminish due to bacterial toxins or food escaping your gut. These toxins can become a serious threat to your cognitive health. The gut contains 70% of your immune cells, and it is where all micronutrients and macronutrients are absorbed into your body. It is a system that is often overlooked, but it plays a huge role in the health of your entire body. Your best bet for staying healthy is to understand the variables that could impact your gut, leading to an overload of bacteria and potentially reducing your cognitive health.

How Your Gut Affects Your Brain

Your brain is a highly nutrient-dependent, and it is vulnerable to invaders, toxins, and stress. In fact, it’s the fattest organ in your body, composed of 60% fat. Your brain cannot feel pain, yet it contains approximately 80 billion neurons, with no pain receptors whatsoever. Because of this, damage could occur to your brain and cognitive health without you feeling it. That’s why it is essential to keep your brain healthy.

Likewise, the state of your gut reflects the health of your entire body. Your gut is your second brain, and it has its very own nervous system. If you have dysbiosis or an imbalance of bacteria in your gut flora, you can quickly develop a myriad of health conditions. An overload of bacterial toxins can lead to dysbiosis as well. Anything that impacts your gut will affect your brain.

Inflammation and cognitive healthThere is a direct connection between your gut and brain, known as the vagus nerve, or cranial nerve number 10. There are more and more studies linking dysbiosis in the gut to health issues including inflammation, food sensitivity, blood sugar issues, obesity, arthritis, and liver dysfunction. But perhaps even more pertinent are the studies showing dysbiosis can lead to brain conditions including Parkinson’s disease, neurodegeneration, and cognitive decline.

The brain to gut highway is a crucial connection, and imbalance in this system can quickly lead to health issues. Intestinal permeability leads to a state of systemic bacterial toxins. Systemic bacterial toxins set the foundation for the development of blood-brain barrier permeability. When toxins get through a permeable gut, they float around the and damage the blood-brain barrier. These bacteria then get into your brain and also have direct access to your central nervous system. This could lead to neurological autoimmune reactivity.

The body sends the immune system to attack the invaders, but instead of eliminating a threat, it learns to identify your own cells as attackers, leading to a state of autoimmunity, in which your body begins to attack itself. This can lead to rheumatoid arthritis, gastrointestinal issues, cognitive decline, adrenal fatigue, insomnia, or even weight gain.

Another consequence of your immune system trying to protect you from leaking toxins is chronic inflammation. Chronic inflammation alters and suppresses your hippocampal neurogenesis, causing damage to your cognitive health. Additionally, when you have a high level of proinflammatory cytokines, they can reduce the proliferation of progenitors that are found in your neuronal lining. Those with a deficient hippocampal neurogenesis lining are at a higher risk of developing mood dysfunctions and cognitive health problems as well.

When Bad Bacteria Takes Over

The balance between good and bad bacteria is delicate, and if you have even a small overload, it can take a toll on your health. When your gut is permeable, or when you have a leaky gut, inflammation results and toxins can be processed directly into your bloodstream. If you have inflammation across your gut lining, that leads to a very high chance of developing blood sugar dysregulation or obesity. Moreover, gut inflammation can also result in an upsurge of cytokines and matrix metalloproteinases, which are enzymes that your body normally releases when you get injured. This leads to musculoskeletal system problems, an increase in arthritis, and the development of joint pain. Your cognitive health can also suffer.

Your liver can experience an overload of toxins being transported to it, with 75% of toxins being transported through your bloodstream, and the remaining 25% transported through your portal vein. Your liver begins to dysfunction and is overloaded with toxins.

When you have an overload of bad bacteria in your gut, it can be a slight percentage, with some serious results. Some types of toxins can be particularly significant.

Cytolethal Distending Toxin

Toxing and cognitive healthThe bacterial cytotoxin CDT, or cytolethal distending toxin, has three subunits within it: CDTb, CDTa, and CDTc. CDTb is the toxic unit of this bacteria and does a great deal of damage to your epithelial cells. Cytolethal toxins are released from bacteria such as E. coli, salmonella, or B. fragilis, but the CDTa and CDTc are actually healthy and are attached to epithelial cells. However, CDTb causes damage to your cytoskeleton from within.

So, for example, when E. coli or another bacteria release CDT, CDTa, CDTb, and CDTc attach and enter your epithelial cells. Once it enters your epithelial cell, CDTb begins to eat at your intracellular structure from within. They immediately begin attacking your tight junctions, the mechanism that connects your cells to each other and creates a protective barrier. Your paracellular junction comes next, important for allowing food antigens to enter your gut. If your body sends immune cells to attack the substances leaking through these weakened barriers, it develops antibodies against food and antigens, creating food intolerance or allergies.


Lipopolysaccharides, also known as LPS, are endotoxins stemming from gram-negative bacteria in your gut system. They have been found in some air pollution particulates as well. These damage your tight junctions, leading to a higher chance of developing leaky gut or autoimmunity. An increased gut permeability also increases the chance of LPS entering into your bloodstream.

When any toxin makes it through your gut and into your bloodstream, it leads to the release of inflammatory compounds such as interleukin- 8 and interleukin- 6. When this occurs, you have a higher risk of experiencing autoimmunity, cognitive health reduction, and internal inflammation. Autoimmunity is exactly what you want to strive very hard to avoid. Once your body goes into autoimmunity, food becomes foe and your body begins to attack itself.

The Role of Chronic Stress

Another common condition that can worsen gut permeability and the risk of autoimmunity and cognitive decline is Adrenal Fatigue Syndrome (AFS). AFS results from being constantly stressed out, which is an increasingly common problem.

Your flight-or-fight mechanism is your body’s natural method for reacting to stress, danger, or fear. It’s normal for this response to occur once in a while due to being chased by a wild animal for example, but it’s not normal for you to experience it all day every day.

In the state of stress, your adrenal glands react by releasing hormones, including cortisol, which is the stress hormone. Normally cortisol gets you ready to fight a threat and helps you calm down afterward, but when you are under constant stress it can disrupt your other systems.

The NeuroEndoMetabolic (NEM) Stress Response system helps your body self-regulate and manage stress utilizing various systems and organs. When the NEM becomes dysregulated, other systems in your body can develop problems. When your adrenal glands are perpetually overworked and get exhausted, they are not capable of pumping sufficient hormones to manage stress or support the NEM systems properly. Subsequently, you can develop Adrenal Fatigue Syndrome (AFS).

AFS and cognitive healthAFS can affect many systems of your body, including your cognitive health, gut health, and immune system.

When toxins, gluten, sugar, or micro-organisms get past your gut lining, they lead to malabsorption, food intolerance, blood-brain barrier, unhealthy cognitive health, systemic inflammation, or autoimmunity. It’s vital to keep in mind, that the very same proteins in your gut epithelial cells are in your blood-brain barrier. When you have a systemic failure in your gut, you will begin to experience inflammatory neurodegeneration.

Inflammation in your body is partly regulated by your adrenal glands, which work to produce anti-inflammatory hormones. Thus, when you develop AFS, your body can’t reduce inflammation as effectively, and many other conditions can develop or worsen. This is why it is so important to do what you can to improve your health.

Doing the Work to Protect Your Cognitive Health

If you are dealing with AFS, either at an advanced stage or at an early stage, you must take proper measures to protect your cognitive health. Whether it’s through taking supplements, exercising, or eating healthy foods, your health is vital.

If you have a stressful lifestyle, it’s time to make changes. Your diet also plays a huge role in the state of your gut. Stress, toxins, and lifestyle habits, such as lack of sleep, are all bad for your gut, and thus impact your brain and every other organ in your system.

If you do develop an unhealthy gut ecosystem, SIBO, or small intestinal bacterial overgrowth, can develop. When E. coli or other harmful toxins enter your small intestine, they eat at the cytoskeleton of your cells, leading to autoimmunity. As Dr. Robert Silverman states, “What happens in your gut, does not stay in your gut.” These gram-negative bacteria, such as E. coli or salmonella, cause direct damage to your DNA and epithelial cells.

Because gut problems can lead to autoimmunity and cross the blood-brain barrier, leading to cognitive health problems, it’s important to take care of your health before things get that bad.

Read Part 2

© Copyright 2018 Michael Lam, M.D. All Rights Reserved.

Dr. Lam’s Key Question

Your brain is interrelated to every organ in your body, especially your gut. If your gut is in a healthy state, it reflects a lot on your brain. Overall health and keeping inflammation low is also important.

Cognitive health