My Gut Has Sprung a Leak!

Written by Ariel Floro | Reviewed by Chidozie Ojobor, Ph.D.

eilings and boats can spring a leak. During heavy rainfall, water drips through a weak ceiling and ruins things that are supposed to be dry. A boat with a hole in it starts sinking because water seeps in where it shouldn’t be. Just like these analogies, your gut can become leaky and cause dysfunction in other parts of your body that are normally protected from inflammatory mediators flowing through the gut. But how exactly does a gut become “leaky”?

The gut is lined with a single-cell layer of epithelium with tight junctions and other cell-to-cell structures between each of the gut epithelial cells. These tight junctions maintain the barrier between the gut and the bloodstream and also regulate gut permeability, allowing for ions to pass through, but not larger compounds. There are multiple proteins, such as zonulin and claudin proteins, that maintain the gut barrier and compounds we ingest can modulate the expression of these proteins to alter gut permeability. For example, gliadin, a protein that is in wheat, can cause zonulin to be released into serum, thus decreasing the integrity of tight junctions. This leads to increased gut permeability and happens in celiac disease.

Once gut permeability is increased, endotoxins, such as lipopolysaccharide (LPS) can leak from the gut and cause inflammation in other areas of the body. LPS is a lipid found on gram-negative bacteria and is recognized by innate immune cells to trigger an anti-microbial response against the pathogen. This explains why celiac disease leads to symptoms like an upset stomach and headaches as endotoxins can travel by the gut-brain axis to cause inflammation in the brain. Dysregulated intestinal permeability has been implicated in other neurological and psychiatric diseases as well as liver diseases, demonstrating the effects that it can have all over the body.

While brief inflammation helps to clear infections, chronic inflammation is what leads to a whole host of diseases, damaging the body. Thus, having a constant leaky gut can contribute to inflammation throughout the body. Increased gut permeability has clearly been indicated in inflammatory bowel disease and other gut inflammatory disorders. There are still portions of it being uncovered in brain and mood disorders, but as mentioned earlier, endotoxin can travel to the brain and cause neuroinflammation which is implicated in Alzheimer’s disease and depression.

With this in mind, the main question is if we can do anything to maintain our gut barrier. The following are some of the proposed ways to maintain gut barrier integrity based on current research:

· Fiber: Within the gut microbiome, there are “good” microbes that ferment dietary fiber into short-chain fatty acids (SCFAs). One of these SCFAs is butyrate which is used as an energy source to cells in the gut. Butyrate has been shown to be beneficial for gut health in various ways, for example through improving assembly of tight junctions. Fiber is found in many fruits and vegetables as well as grains, like oat and wheat, and mushrooms.

· Probiotics: Certain probiotic strains have been implicated in decreasing gut permeability by modulating the expression of tight junction proteins. Two of these stains include Lactobacillus plantarum and E. coli Nissle, which may be found in certain probiotic supplements or fermented foods. While this is a promising treatment, investigation is still underway to clearly understand the use of probiotic treatment for gut permeability and inflammatory gut disorders.

· Exercise: Exercise is a form of hormetic stress, which is temporary stress that reaps benefits in the long-term. During exercise, muscle fibers are destroyed, but the body’s repair mechanisms grow them back stronger than before thus demonstrating “good stress”. Similarly, it has been suggested to be a type of hormetic stress for gut health. Initially, gut permeability actually increases after exercise, but some studies have shown improved gut barrier integrity in the long-term after a consistent exercise routine. Further research is needed to clarify the relationship between intestinal permeability and exercise.

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References:

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