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What is a leaky gut?

Leaky Gut Syndrome

Leaky gut syndrome or increased intestinal permeability has been getting a lot of attention recently in the functional medicine world (but, sadly, it still isn't widely recognized by the medical community) since it affects our health on multiple levels and can impact every system in the body.

Leaky gut is weakening, inflammation or damage of the lining of the intestines (the gut barrier).

tight junctions in the gut
Gut gate keepers


Our gut (small and large intestines) is lined with a single layer of cells that are held together by tight junctions. These absorptive cells play important roles in the digestion of food, absorption of nutrients, and - our focus for today - protection of the human body from microbial infections, viruses, partially digested food particles, pathogenic bacteria, parasites, yeasts from entering the body.

The gut barrier is a major part of the immune system (up to 85%!) allowing molecules to enter and exit the gut and warding off the molecules that shouldn’t be entering. It protects the "inside" world from the "outside" world and is a huge factor in regulating our whole body health.

This is our first line of defense, our immunity.

Types of permeability

There are two types of permeability (or movement across the gut wall) by either transcellular diffusion (through the cell) or paracellular uptake (between the cells).

The layer of cells that is our gut lining is held together by small gaps - these are tight junctions. They allow nutrients into the bloodstream and keep potentially harmful substances out and act like gate keepers of the gut lining by keeping the gate open only to small molecular weight particles.

When the proteins go in these gaps between the cells, some of them get stuck - and once the tight junction proteins are compromised, they keep the gate open and allow antigens and bacteria to pass through into the underlying mucosa. This is paracellular permeability.

Transcellular intestinal permeability happens when not only tight junction proteins are destroyed, but the entire cell has been destroyed causing the "leakage" of large particles and molecules like proteins and bacterial products that wouldn't be able to pass through the cell membrane or the paracellular space due to the size with the healthy tight junctions and resulting in a more serious destruction of the GI track.

That's why some people have no symptoms at all and some have many hardcore symptoms - it all depends how badly the gut lining has been damaged.

When the gut barrier receives the molecules that don't necessarily belong there, the immune system gets confused and begins to react negatively by creating inflammation inside the gut and attacking your own tissues.

Normal vs Leaky gut
Leaky gut under the microscope

What causes leaky gut?

We have billions of bacteria in the gut microbiome (or gut flora) that play a major role in protecting the gut lining and ensuring that the junctions stay healthy and tight. Unfortunately, environmental factors like stress, medications, toxins, food additives and chemicals can change the healthy balance of good and bad bugs causing the gut environment to become imbalanced which leads to the inflammation in the gut.

Imagine how your gut lining is constantly being attacked and is repeatedly being injured causing it to become porous and leak. But who are the attackers?

Some of us may have a genetic predisposition and may be more sensitive to changes in the digestive system, but our DNA is not the only one to blame. Modern life may actually be the main driver of gut inflammation. Things in the list below are believed to be causing the gut inflammation:

  • Poor diet (like SAD - Standard American Diet with low fiber, high sugar, high processed foods)

  • Prolonged stress, which can weaken the immune system and inhibits your body’s ability to eliminate harmful bacteria and viruses, resulting in inflammation and leaky gut.

  • Dysbiosis, or an imbalance between helpful and harmful species of bacteria in the GI tract.

  • Toxins overload - we come across more than 80,000 chemicals and other toxic substances on a daily basis. However, the main culprits are antibiotics, pesticides, and contaminated tap water.

  • Chronic overuse of alcohol, acid blockers, proton pump inhibitors (PPIs) and NSAIDs, like aspirin and ibuprofen.

  • Chemotherapy and radiation therapies that degrade the intestinal mucosa.

  • Chronic inflammatory conditions, such as IBD and celiac disease.

  • Nutrient insufficiency and low stomach acid - decreased stomach acidity doesn't allow you to completely digest food, which then remains and rots in the GI tract, resulting in inflammation, which damages intestinal lining leading to leaky gut.

As you can see the potential causes of the leaky gut are quite diverse and broad but there is no doubt that living a healthier lifestyle, eating a proper diet for your body and health state, avoiding toxins - these all can help lowering inflammation in the body and especially in the gut.



Thank you!

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