Your intestinal barrier is one of your body’s most essential defense barriers. The contents of your GI tract are on the outside of your body. When they are brought across the lining of your GI tract into your cells and blood stream, they are now inside your body. This barrier protects you from the outside world. Protecting your body from pathogens, bacteria, toxins, viruses, food and debris is a tall order; especially when humans seem to do a lot to cause insult and injury to their gut.

If this barrier breaks down, this is called leaky gut (or, intestinal permeability).

Leaky gut means that the cells are no longer maintaining a fortified barrier. The resulting intestinal permeability allows toxins, debris and undigested food particles to cross into the blood stream, triggering intestinal and systemic inflammation. This will increase your risk of autoimmunity, loss of oral tolerance (food intolerance and food allergies), and a risk for skin conditions, like eczema and psoriasis.

Leaky Gut symptoms include bloating, gas, inflammation, joint pain, can trigger autoimmune conditions and neural inflammation. WAIT! What does neural (brain) have to do with intestinal permeability (gut)? Earlier I wrote that leaky gut can drive systemic inflammation, and this includes inflammation in the brain.

Leaky gut or intestinal permeability, can impact the brain by triggering neural inflammation. It can also lead to a breakdown of the blood-brain-barrier and it can contribute to neurological conditions like Parkinson’s and it can even contribute to mental illness. This is the gut-brain connection, which is a direct signaling path from the gut to the brain and brain to the gut.

One of the main pro-inflammatory mediators for systemic inflammation, and neural inflammation, is lipopolysaccharides (LPS). The microbes in your intestinal tract are a balance of mostly beneficial gram-positive bacteria (think Lactobacillus and Bifidobacterium) and some unbeneficial gram-negative bacteria (think Bacteroides and Prevotella).

When you poop, half of the bowel movement is biomass sloughing off. Although you can’t see bacteria with the naked eye, so much of it sloughs off (bacteria is continually ‘turning over’ – reproducing and dying off) that it makes up 50% of the mass of your bowel movement!

If an overgrowth of gram-negative bacteria is present, as these bacteria turn over, they will dump their cell’s contents. LPS is in the cell membrane of gram-negative bacteria. When LPS is dumped at high levels into the intestine, this will trigger systemic inflammation. LPS can also cross into the blood and it can cross into the blood brain barrier. It is also suggested, that LPS can activate the vagus nerve – which is a direct unguarded nerve route from the gut to the brain. LPS induced systemic inflammation is called metabolic endotoxemia.

Leaky Gut → inflammation and bacteria imbalance → LPS → Metabolic endotoxemia → drives brain disorders.

A study linking intestinal permeability with schizophrenia, wrote, “In conclusion, patients with schizophrenia were shown to have a higher rate of abnormally increased gut permeability compared to their healthy counterparts. Moreover, there may be a correlation between gut permeability and the cognitive and cellular immunity function of the patients.”(1)

Another study links leaky gut with Parkinson’s Disease (PD) Increased bowel permeability, called “leaky gut,” is typical for patients with early PD (Forsyth et al., 2011). They went on to say, “…when the function of the intestinal barrier is disrupted with subsequent inflammatory processes and increased oxidative stress.”(2)

This study titled: Leaky gut, dysbiosis, AND enteric glia activation: the trilogy behind the intestinal origin of Parkinson’s disease, showed that leaky gut drives glial cell activation in the brain, which in turn drives neuroinflammation in the asymptomatic stage of Parkinson’s.(3)

If leaky gut is caught and treated early enough, this has the potential of stopping Parkinson’s from developing.

Or this study, titled: Gut dysbiosis in severe mental illness and chronic fatigue: a novel trans-diagnostic construct? … gut dysbiosis triggers a chronic low-grade pro-inflammatory status in the host by increasing the permeability of the gut barrier (“leaky gut”) and by facilitating the translocation of bacterial antigens into the bloodstream (“endotoxemia”)(4)

Whenever a patient reports brain symptoms to me – hard time concentrating, brain fog, brain fatigue, moodiness, leaky gut and metabolic endotoxemia are on the top of my mind. I run a leaky gut test to rule out intestinal permeability and metabolic endotoxemia.

Order Your Leaky Gut Test Here

1. Ishida I, Ogura J, Aizawa E, Ota M, Hidese S, Yomogida Y, Matsuo J, Yoshida S, Kunugi H. Gut permeability and its clinical relevance in schizophrenia. Neuropsychopharmacol Rep. 2022 Mar;42(1):70-76. doi: 10.1002/npr2.12227. Epub 2022 Jan 25. PMID: 35080340; PMCID: PMC8919127.
2. Harsanyiova J, Buday T, Kralova Trancikova A. Parkinson’s Disease and the Gut: Future Perspectives for Early Diagnosis. Front Neurosci. 2020 Jun 17;14:626. doi: 10.3389/fnins.2020.00626. PMID: 32625058; PMCID: PMC7313629.
3. Seguella L, Sarnelli G, Esposito G. Leaky gut, dysbiosis, and enteric glia activation: the trilogy behind the intestinal origin of Parkinson’s disease. Neural Regen Res. 2020 Jun;15(6):1037-1038. doi: 10.4103/1673-5374.270308. PMID: 31823880; PMCID: PMC7034261.
4. Safadi, J.M., Quinton, A.M.G., Lennox, B.R. et al.Gut dysbiosis in severe mental illness and chronic fatigue: a novel trans-diagnostic construct? A systematic review and meta-analysis. Mol Psychiatry 27, 141–153 (2022). https://doi.org/10.1038/s41380-021-01032-1