Leaky gut and autoimmunity - What are the links?
The gut (a.k.a. digestive tract) is not just a tube that absorbs nutrients and gets rid of waste - it’s a complex alive system that’s a huge foundation of health. And not just gut health, but the overall health of our bodies and minds. We know how important it is to get all of our essential nutrients from food - and this is a big part of what our digestive tract does. But, there is way more to the story than just that.
When the gut is not working properly, symptoms can appear. Yes, typical gut and abdominal symptoms, but also other seemingly unrelated symptoms. Did you know that things like allergies and autoimmunity have been linked with gut problems?
Let’s look at one gut problem in particular (you may have heard about this lately) - leaky gut. This literally involves tiny “leaks” in our gut lining that can allow more than just needed nutrients and water into our bodies. Researchers are looking at this, and I want to share the latest with you!
What is “leaky gut” linked with?
The “gut” is part of the digestive system, mainly the intestines, which are located in the abdomen. It’s an alive and very complex “tube” that acts as a gateway deciding what will enter the internal circulation of the body, and what must not get by. It digest and absorbs nutrients and water. It prevents toxins and “bad” microbes from being absorbed. And it shuttles all the waste to continue on and be eliminated.
You may think that symptoms of a leaky gut (a.k.a. “intestinal permeability”) are felt in the gut, and you’re right...to a point. Would you be surprised to know that lots of other symptoms and conditions are linked with leaky gut?
Leaky gut has been associated with:
● Autoimmune diseases (e.g. Type I diabetes, celiac disease, etc.)
● Inflammatory Bowel Diseases (e.g. ulcerative colitis, Crohn’s)
● Psychological stress and mental health
● And more!
Researchers are still figuring out the exact role that leaky gut plays in these conditions. Either way, the connections are there, and there are things that you can definitely do to improve your gut health. But first, how is our gut structured, and what can promote it to leak?
Gut structure - Three layers of our gut lining
Our guts have a three-layer lining that helps to allow things we need in, and keep harmful things out.
The first (outermost) layer is just one-cell thick. It’s a barrier that absorbs the nutrients and water we need, and physically prevents undigested compounds, toxins, and bacteria from getting in. Laid out flat, this layer makes up the largest surface area between the internal circulation of our bodies and the outside world (i.e. what we eat and drink).
The second layer is mucus. This mucus provides physical separation between the outermost enterocyte layer and the microbes and food that are inside the centre, or “lumen,” of the gut. It also contains special proteins that help fight against invaders. This mucus and its special compounds are produced by the enterocytes.
The third (innermost) layer inside our gut lining is our friendly resident gut microbes. Our guts contain billions of microbes - over 1 kg worth. Taken together, they’re sometimes referred to as a “superorganism.” These microbes include bacteria as well as other types of friendly microbes.
This layer of gut microbiota has two major functions to help promote a healthy gut lining:
● They crowd out “bad” bacteria by taking up space and eating the “good” food (i.e. fibre and resistant starch, which we’ll get into in a bit).
● They help to regulate the digestion and absorption of nutrients to nourish the first-layer enterocytes. One of the types of compounds they produce are called “short chain fatty acids” (SCFAs). These are considered to be anti-inflammatory and are also used as fuel for the enterocytes.
When the three layers aren’t working optimally, the tight junctions loosen, and leaks occur. This allows unwanted things to enter into the body’s circulation. This is how gut health affects our overall health.
Leaky gut, allergies, and autoimmunity
Allergies and autoimmunity are directly linked to our immune system. They result when our immune system works a bit too hard - when our immune cells become a little too active.
Allergies occur when our immune system is activated to fight things that are not harmful, like certain foods, pollen, or pet dander. The body thinks they’re dangerous invaders that must be fought, and sends out immune cells that cause inflammation to try and eliminate the allergen.
Autoimmunity, on the other hand, is when our immune system is activated to fight our own cells and tissues. The immune system becomes “intolerant to self.” For example, type 1 diabetes (an autoimmune disease) occurs when our immune system fights the insulin-producing cells in our pancreas. After continued inflammation, enough of these cells die and we eventually need to start monitoring our own blood sugar levels and provide our bodies with external insulin. This occurs more often in people who have type 1 diabetes in their families.
Many things can contribute to autoimmunity, and leaky gut may be a bigger factor than we once thought. This is because of the impact of allowing undigested food, bacteria, etc. enter our bodies and how our immune system tries to fight them. A large part of our immune system is located just on the other side of that one-cell thick layer of enterocytes.
When our bodies detect things in our internal circulation that don’t belong (like undigested food or bacteria) our immune system kicks in. This immune response to things that “leaked” into our bodies can cause the release of even more inflammatory compounds this time inside our bodies and bloodstreams (i.e. on the other side of the first layer of enterocytes). The allergic and inflammatory responses that happen around our guts may affect the gut directly. But, once these are absorbed into the bloodstream, they can affect other parts of the body too.
This is the connection we see between leaky gut, allergies, and autoimmunity. It’s not just the leaky gut, it’s the interactions between what leaks into our bodies and our immune system’s response to them.
Having a healthy gut microbiota plays an important role in how our immune systems mature from when we were infants. Dysbiosis in our gut at an early age can promote changes in our immune response, and increase the risk of allergic and autoimmune diseases.
It seems that gut dysbiosis and “leaky gut” might be part of the chain of reactions that lead our immune cells to start attacking things they really don’t need to.
Leaky gut, or “intestinal permeability” is linked with many conditions of the gut, the body, and the mind. While research is still figuring out exactly how this happens and what comes first, there are definitely steps you can take today to help optimize your health. Learn about what you can do about leaky gut here!
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