The impact that our digestive system and gut bacteria have on the health of our entire body goes largely unnoticed until a disease or other dysfunction develops. And even then, the link between the gut and the disease often goes unrecognized. After all, who would think to look at the gut when someone has multiple sclerosis? The truth is, however, that our gut has powerful influence over how well our body operates and is the number one underlying cause behind all chronic disease, including autoimmune disease. This is why it’s so important to support the health of your gut and maintain a balanced microbiome of healthy gut bacteria. 


How Our Gut Affects Our Whole Body


Let’s take a quick look at some of the ways in which our gut communicates with and controls various functions within our body:


Gut and Immune System:

It is said that our gut contains between 70% and 80% of the cells that make up our immune system. These immune cells interact with the bacteria in our gut and are sensitive to any changes in our microbial environment. Our gut can be prompted to “switch on” our immune system for short periods of time, such as when we’re fighting off an infection, or for long periods of time, which is unhealthy and leads to chronic inflammation and disease, including autoimmune disease.


Gut and Inflammation:

The lining of our intestine is designed to transfer nutrients from the food we eat to our bloodstream, where they’re carried into our body tissues. This lining is composed of a single layer of intestinal cells that are lined up tightly side-by-side (called “tight junctions”). These tight junctions are so tight that they can only allow small particles (micronutrients) into the bloodstream. 

However, if that tight cell lining gets loose (or “leaky”), larger particles escape our intestine and pass into our bloodstream. These larger particles include harmful bacteria, bacterial toxins, large proteins, and undigested food bits. Once these hit our bloodstream, our white blood cells (immune cells) recognize that they don’t belong there and launch an attack. Anytime our immune system launches an attack, inflammation is present. When the cause of the attack (such as a leaky gut) is ongoing (such as the unhealthy food we eat), then we get chronic inflammation. Chronic inflammation is a key instigator of chronic disease. 


Gut and Mood/Cognition: 

Furthermore, our gut bacteria impacts which neurotransmitters are made in our digestive tract (95% of our serotonin is made by our gut bacteria!). Neurotransmitters include GABA, serotonin, dopamine, norepinephrine, melatonin, and others. These chemical messengers collectively impact our mood, alertness, stress response, memory, learning, motor control, and digestive function. Similar to immune cells, the production of neurotransmitters are also sensitive to any alterations in gut bacteria. 


Gut and Brain:

Our gut is often referred to as our “second brain.” As we learned in school, our central nervous system (CNS) comprises our brain and spinal cord where millions of electrical signals are sent back and forth between our body and brain every second. Similarly, we also have an enteric nervous system (ENS) located within our digestive system that controls our gastrointestinal secretions, motility (peristalsis), local blood flow, and overall digestion. It also modulates our immune system and endocrine (hormone) responses. Lastly, the ENS interacts with our gut microbiome and the nutrients from our food. The ENS of our gut communicates with the CNS of our brain through a long nerve called the vagus nerve. This connection is what describes the “gut-brain axis” where any imbalance or dysfunction of our gut health is immediately broadcast to our brain.


Gut and Thyroid:

The thyroid helps control the function of our muscles, heart, digestive system, bone integrity, and brain development. This important gland uses a hormone called TSH, which produces two other hormones, T3 and T4. T4 is an inactive hormone and must be converted into T3, the active form. Our gut bacteria are charged with converting about 20% of all T4 into T3. This conversion can only happen, however, with a certain enzyme that is produced by healthy gut bacteria. Harmful gut bacteria, on the other hand, contain a toxin called LPS that reduces levels of thyroid hormone and decreases TSH (thus lowering production of T3 and T4). Furthermore, the T3 hormone can be reduced by constantly high cortisol levels caused by stress and gut inflammation. 


Causes of Bacterial Imbalance


You may have noticed by now that the connection between gut health and chronic disease seems to involve the health of our microbiome. And you’d be right! We can’t talk about gut health without also talking about gut bacteria and the diversity, quantity, and composition that they hold. The health and balance of our microbiome is critical to the health and balance of our entire body. 

An imbalance in quantity or diversity of gut bacteria is called dysbiosis. Dysbiosis is caused by a number of factors. The overuse of antibiotic medication wreaks havoc on our gut bacteria and causes a significant reduction in the diversity of bacterial species. Chronic stress slows the motility, or movement, of our GI tract, thus altering the composition of our gut bacteria species. Diets high in sugar and processed carbs and low in fiber are associated with lower diversity of bacterial species as well as higher levels of harmful bacteria. Toxins found in food such as PCB’s, dioxins, pesticides, and foodborne chemicals produced in high-heat cooking, can all cause inflammation in the gut as well as an imbalance of microbiome functions and activity.  


Where Do We Go From Here?


We’ve established that the health of our gut, with special focus on our microbiota, play a huge role in the health of other areas of our body. We have seen how our gut acts as a “second brain,” how it houses the majority of our immune system, and acts as strict gatekeepers against harmful compounds entering our bloodstream. Our gut further impacts our mood, our thyroid, our sleep, and our stress. It truly is an incredible system. One that holds enormous power over the function and wellbeing of everything else. So how do we tame it? How do we keep it healthy? 

Last week, we talked about the 5R protocol for healing the gut. Each “R” in this protocol stands for one of the five phases of the protocol. In order, they are: Remove, Replace, Repopulate, Repair, and Rebalance. The aim of the 5R protocol is to normalize digestive function, balance out healthy gut bacteria, make dietary changes that avoid harmful foods, and repair the damage of our gut lining (getting those gatekeepers to do their job). Our recent blog outlines further details about this 5R program, here.  

Healing the gut while avoiding further damage or insult can be tricky and overwhelming at times. Our team at Healthy Connections can help you navigate it successfully! Schedule a free discovery call with us today!