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, autoimmunity, and mental health have been linked with gut problems? Let’s look at one gut problem in particular (you may have heard about this lately) - leaky gut or what researchers refer to as intestinal permeability . 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, as well as give you some helpful strategies to optimize your gut health, for overall health!
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).
This layer has at least seven different types of cells, and 90% of them are one type called “enterocytes.” These enterocytes actively absorb what we need and keep out what we don’t. They also help to create and regulate the other two layers.
Most enterocytes are replaced with new ones every 3-5 days or so.
Enterocytes are held together with different types of bonds. The one most studied is called a “tight junction.” These tight junctions are made up of several types of protein. When they loosen, it creates tiny holes (or permeations) in this first layer since the cells are not “stuck” together as much as they should be.
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. We want that mucus layer to be nice and thick to provide a better barrier between the one-cell layer of enterocytes and protect them from “bad” bacteria that can get in there.
Animal studies show that mice fed a diet low in fibre had thinner mucus barriers.
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.
Next week on Part 2:
Leaky gut and our gut microbes
Leaky gut, allergies, and autoimmunity