What Is Leaky Gut Syndrome?

Increased Intestinal Permeability

Leaking faucet
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Leaky gut syndrome refers to a theorized condition in which the lining of the intestines has become compromised. Leaky gut syndrome is more accurately known as increased intestinal permeability.

The lining of our intestines has a very important job. It needs to be open enough to allow nutrients and fluids to enter into our bodies, yet be tight enough to keep out unwanted substances. An important anatomical structure to become aware of is the tight junction.

When these tight junctions are intact, intestinal permeability works optimally. When the functioning of these tight junctions become compromised, there is an increase in intestinal permeability, and therefore a state of "leaky gut". When this happens, unhealthy substances get through the intestinal barrier where they can cross into the bloodstream and interact with the immune system. This immune system reactivity is theorized to contribute to inflammation and to trigger chronic health problems and symptoms.

What Causes Leaky Gut Syndrome?

It is theorized that the health of the intestinal barrier can be negatively impacted by many factors, including:

  • Bacterial or viral infections
  • Certain medications
  • Poor diet
  • Excessive alcohol intake

An unhealthy balance of gut flora, known as dysbiosis, is also theorized to play a role in increased intestinal permeability.

In addition, like a chicken and egg problem, it is unknown if certain health conditions can cause an increase in permeability or if the increased permeability causes the health problem.

Health Problems Associated with Intestinal Permeability

The following health problems have all been theoretically associated with increased intestinal permeability. In each case, inflammatory substances let through by the increased permeability is thought to be carried through the bloodstream to other parts of the body where they contribute to or cause symptoms.

It is important to note that at this point any discussion of a connection between increased intestinal permeability and any of the following health problems is only at the level of a hypothesis, not anywhere near any sort of a firm conclusion.

A Word of Caution

As a psychologist, I must say that I hate the original name "leaky gut" due to the awful imagery that it evokes. We all know that our bodies are very reactive to imagery (give a teenage boy some erotic pictures and see what happens to their bodies!). I have also heard many "leaky gut" experts talk about the syndrome and describe how "chunks of food" enter the bloodstream, causing all sorts of havoc. My concern is that worrying about "how leaky your gut is" is only going to cause unnecessary anxiety, and we all know that anxiety can contribute to unwanted digestive symptoms!

It may be of help to become re-acquainted with basic biology. When we eat food, the process of digestion, or the breaking down of food into its nutritional components, starts immediately. Chewing our food and enzymes from our saliva both contribute to this process. In our stomachs, food is further broken down by pepsin and hydrochloric acid. If you have ever encountered hydrochloric acid in real life, you know that it is very powerful stuff. Therefore, by the time the food you have eaten has made its way to your small and large intestine, it has been pretty much broken down into the level of its micronutrients, not large chunks of food! Granted, sometimes you may see a small bit of undigested food passing its way through your stool, but believe me, a piece that big is certainly not making its way into your bloodstream!

The Bottom Line

Here is a much more helpful way of looking at what is going on: As of now, research is looking into whether, for some individuals, the cells of the intestinal lining are not providing the barrier functioning that they should be, resulting in a state of increased intestinal permeability. If this is the case, it is possible that some select molecules may be getting through this barrier and perhaps triggering an immune system response that is contributing to or directly causing symptoms and/or disease in other parts of the body.


Bischoff, S. et.al. "Intestinal permeability – a new target for disease prevention and therapy" BMC Gastroenterology 2014 14:189.

Odenwald, M. & Turner, J. "Intestinal permeability defects: Is it time to treat?" Clinical Gastroenterology and Hepatology 2013 11:1075-1083.

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