Leaky Gut and Psoriasis: Is There a Connection?

As a Microbiologist, I’m continuously fascinated by new developments in my field, especially surrounding the gut microbiota and our digestive systems, which are involved in many more pathologies than we ever thought possible.

The science behind a leaky gut

For example, there is an increasing amount of evidence that links autism and microflora (called the gut-brain axis), and even speculation that it could be (in part) caused by clostridial toxins early in childhood^1,2. We are learning that the microbiome of skinny and obese persons is very different and that these bacteria when injected into mice can actually cause them to gain or lose weight³.

Dysbiosis in your gut microbiota could also be involved in allergies and asthma⁴, eczema, and even autoimmune lupus ⁵. I could go on for hours because the field is so ripe with new developments.

What we know about leaky gut and psoriasis

Although this emerging research is exciting and extremely promising, it is preliminary, and there is no current scientific consensus in any of these areas. And where there is a vacuum, there is usually something to be sucked into that space!

In this arena, I find that to be the recurring term “leaky gut,” a somewhat catch-all phrase that bears the responsibility for many of our ills. But how much do we actually know about leaky gut, and is there a demonstrated connection to psoriasis? Let’s science!

What is leaky gut?

Leaky gut is more commonly known in science as increased, or dysregulated, intestinal permeability. Our intestines have two very important roles in our body, they absorb nutrients from food and they protect the body against bacteria, viruses, and other foreign invaders.

There’s the physical intestinal barrier, made up of epithelial cells and mucosa, and the immune barrier, all of the immune cells and immune proteins that interact with the intestine to keep us safe.

Connecting the immune system

Did you know that 80% of your immune system resides in your digestive tract? No wonder our microbiome is so integral to overall health (and plants the seed of suspicion that all this talk of autoimmunity being closely tied to our GI health might actually have some merit).

So, in order to absorb the nutrients from digested food, intestinal permeability is important, but too much permeability means undigested food, bacteria, and their toxins (called endotoxins or LPS) that normally pass through your GI tract, instead migrate across the intestinal barrier and into your bloodstream.

The cause versus risk factors

What do these escapees do? They cause low-grade inflammation because the immune system must constantly be in response mode.

You can read more about this process here ⁶, and discover why the authors concluded that “…stress-induced disrupted barrier function in parallel with elevated circulating endotoxin levels may underlie disease onset and progression and should be considered much more than just a risk factor for chronic disease; it could be a cause.” (Is it just me, or do scientists love a good run-on sentence?)

Measuring leaky gut

Leaky gut is assessed in clinical settings by assays that measure the concentration of certain particles, usually from your urine, that are not supposed to cross the intestinal barrier. The higher the concentration of these particles after ingestion/injection, the more permeable your intestinal barrier is thought to be.

Doctors can also measure the amount of LPS/endotoxin (a component of bacterial cell walls) in your blood, or how many circulating antibodies against LPS you have in your bloodstream. These tests indicate what level of bacterial movement across the intestinal barrier is happening. You may have heard this defined as low-level endotoxemia (note: bacteria and their toxins are most certainly supposed to remain IN your intestines!)⁷.

Can leaky gut be induced experimentally?

Okay, so we know what leaky gut is and how we measure it, but do we know what causes it? Can we reproduce it in a clinical setting? Oh yes we can! In a 2014 paper in the Journal of Gastroenterology, scientists created and visualized the creation of inflammation and intestinal gaps (i.e. leaky gut) in IBS patients after the introduction of wheat, yeast, milk, and soy.⁸.

In addition to that, the typical Western diet, one that is high in fat, refined sugar, and low in fiber, consistently increases intestinal permeability in animal models⁷.

Fructose solutions can produce the same result, which may be why those with “sensitive tummies” often respond well to low FODMAP diets. We also know that certain drugs, like antibiotics and NSAIDs, disrupt the normal microbiome and affect permeability.

Is there an evidence-based connection to psoriasis?

The short answer is no. Two experiments prior to 2000 were done assessing the intestinal permeability in psoriasis patients vs. healthy controls; one found no difference, the other found intestinal permeability in psoriasis patients was increased.

But, there have been no wide-scale studies to look at how treatment of leaky gut may improve psoriasis symptoms. There is, however, an accumulating amount of evidence for the positive effects of therapeutic intervention of intestinal permeability for those with IBD, obesity and metabolic syndrome, type 1 diabetes, celiac disease, and HIV infection⁹.

Can leaky gut be improved?

Okay, so you don’t want to wait around for the scientific powers that be to tell you that healing your gut will heal your skin. Can science at least tell us what to ingest? Every year there are more studies demonstrating interventions that reduce hyperpermeability of the intestinal barrier.

Notably, abandon the Western diet of high fat, low-fiber, refined sugar foods. Increase the variety of the fruits and vegetables you eat, as fiber is well known to improve the microbiome.

A change in diet

One study was able to demonstrate that removing gluten, milk, and refined carbs from the diet reduced intestinal permeability in patients with Chronic Fatigue Syndrome¹⁰. Supplemental glutamine and zinc are two other common crop ups in these articles, as well as other anti-inflammatory products like curcumin and quercetin^7,10.

As a final finding, NSAIDs have been conclusively linked to increased permeability and inflammation of the intestinal barrier, so this may be further consideration for those interested^11,12.

Final thoughts

As with everything, drastic changes should be talked about with your healthcare team to make sure they’re a good choice for you.

While increasing fruit and vegetable consumption probably doesn’t warrant a trip to your GP, deciding to abandon your meds and load up on supplements definitely does.

Wishing you all happy guts and lots of good bugs!