The term “leaky gut syndrome” refers to a condition known as increased intestinal permeability. This condition occurs when a layer of cells in the intestines (the epithelial barrier) becomes more permeable, allowing certain substances to enter the bloodstream. Although researchers have established a connection between leaky gut syndrome and some gastrointestinal (GI) disorders, some studies have suggested that the condition may also play a role in other autoimmune diseases, like psoriasis.

What Is Leaky Gut Syndrome?

All of the body’s surfaces are covered with tightly packed cells known as epithelial cells. These cells perform many different functions. Together, they form a protective layer called the epithelium.

The intestines’ epithelial barrier (the intestinal epithelium) is composed of a single layer of intestinal epithelial cells (IECs). These cells control what substances can pass between the intestines and the bloodstream. As with other epithelial cells, they are packed closely together. Protecting the spaces between the cells is the tight junction (TJ). The TJ helps regulate what is let in and out of the intestines, a quality known as permeability.

In healthy intestines, the IECs form a tight protective barrier and prevent certain substances in the intestines from entering the bloodstream. It is important to note that the intestinal epithelium is not 100 percent impenetrable — and for good reason. In addition to keeping harmful substances out of the bloodstream, the intestinal epithelium is also responsible for allowing certain substances to pass through its barrier.

In certain people, however, the spaces between the IECs widen, increasing the intestines’ permeability. This can lead to inflammation and affect the digestive tract’s naturally occurring bacteria. If this happens, it can have significant impacts on the GI tract and the body as a whole. This increased intestinal permeability is what some practitioners refer to as “leaky gut syndrome.”

The Relationship Between Increased Intestinal Permeability and Psoriasis

Although leaky gut syndrome is not recognized as its own disease, changes in intestinal permeability have been linked to a number of chronic diseases, including type 1 diabetes and celiac disease. It has been proposed that certain health conditions may affect the intestines’ permeability, creating a leaky gut that allows bacteria, toxins, and other substances to enter the bloodstream. Researchers have also suggested a leaky gut may also play an important role in the development of autoimmune diseases such as psoriasis.

Some people are genetically predisposed to developing psoriasis — particularly those with a family member with the condition. That said, fewer than 10 percent of people who are genetically predisposed to autoimmune diseases go on to experience symptoms. Some scientists believe that environmental factors are responsible for triggering the development of diseases like psoriasis.

Some researchers believe that for people with a higher risk of such diseases, having a leaky gut may allow substances that can trigger or worsen the disease to enter the bloodstream. This may be why people with autoimmune diseases have been found to have TJ dysfunction in the intestinal epithelium. Research has also found that disease-causing bacteria can lead to a leaky gut and trigger the symptoms of autoimmune diseases.

For these reasons, some GI researchers have suggested that the traditional understanding that environmental and genetic factors alone lead to autoimmune disorders is incomplete. Instead, they believe that genetics, immune system dysfunction, and environmental triggers — combined with a weaker intestinal barrier and disruption of the gut microbiome (gut flora) — may play a role in the development of some autoimmune disorders.

What Causes Increased Intestinal Permeability in Psoriasis?

Researchers are not yet sure what causes increased intestinal permeability, either on its own or alongside psoriasis. The fact is that everyone’s intestines are permeable to a certain degree.

Several factors have been cited as being responsible for problems with the intestinal barrier and gut microbiota. Some include excessive alcohol consumption, stress, dietary factors (such as eating high-fat and high-sugar diets), infections, and burn injuries. These factors may cause a leaky gut in people who are more sensitive to problems in the GI tract.

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