Leaky gut syndrome (LGS) is a proposed gastrointestinal disorder that affects the lining of the intestines. That being said, a certain level of controversy exists about whether or not leaky gut actually exists as it is defined, since diagnosis of the disorder is incredibly difficult (if not impossible). Regardless, when a person is believed to be afflicted by this syndrome, tight junctions in the intestinal walls may not be working properly, resulting in tiny gaps that allow bacteria and other toxins to pass into the bloodstream (Campos, 2017). Increased intestinal permeability can often be found in people with diseases such as Crohn’s disease. However, intestinal permeability is a symptom of these ailments, not a cause; it does not lead to anything more than inflammation of the bowel walls, and it is not leaky gut syndrome.
The gastrointestinal tract is a pathway of connected organs, running from your gums to your bum! The organs that make up the GI tract are the esophagus, the stomach, and the small and large intestines. Put simply, digestive enzymes within the stomach and small intestine break down nutrients in food and drink. These smaller molecules are then used by the body for energy, growth, and repair.
The intestines are crucial when it comes to protecting the body from harmful bacteria and toxins. The tight openings in the intestinal walls allow water and these nutrients to pass into the bloodstream, all while keeping the harmful substances inside. With leaky gut syndrome, these openings become wider resulting in hyperpermeability, which allows food particles, bacteria, and toxins to enter directly into the bloodstream (Campos, 2017).
The intestines are home to a wide range of microbes which help digestion, protect the intestinal wall, and support normal immune function. Research shows that LGS may involve imbalances in the microbiota, which can trigger the body’s immune response, resulting in gut inflammation and increased intestinal permeability (Morris et al., 2016).
While many doctors and healthcare professionals do not actually recognize leaky gut syndrome as a diagnosable condition, current scientific evidence suggests that it may contribute to a wide range of medical conditions.
As mentioned, leaky gut, or “increased permeability” is not fully recognized by the medical community at large, which makes finding symptoms a tough task. Many of the symptoms are shared with other health conditions, making the disorder difficult for doctors to identify. Leaky gut may cause or contribute to the following possible symptoms:
These symptoms overlap with many other health conditions, leading experts to believe that leaky gut may actually contribute to their manifestation. While it is not clear if LGS is a cause or a symptom, it has been linked to irritable bowel syndrome, Crohn’s disease, celiac disease, diabetes, and food allergies, among others. A peer-reviewed study suggested that increased intestinal permeability may actually contribute to the development of inflammatory bowel disease (Lee, 2015). However, more peer-reviewed studies need to be conducted before any firm conclusions can be drawn.
Furthermore, scientists have closely looked at the gut-brain axis, which is the relationship between the GI tract and the brain. Some research has shown that leaky gut may be a factor for mental health conditions such as anxiety and depression (Clapp, 2017)
While experts do not yet definitely know what causes leaky gut syndrome, there are various risk factors that can disrupt the gut microbiota and contribute to increased intestinal permeability. Some examples are:
With autoimmune disorders being a risk factor, the question of whether or not LGS is a cause or symptom of a disease like inflammatory bowel disease once again becomes relevant, since IBD is an autoimmune disorder.
While diagnosis is incredibly difficult (if not impossible) as mentioned, there is one specific test that some physicians will use in order to test intestinal permeability. The test is called the mannitol and lactulose test. Both of these are water-soluble molecules that the body cannot use. Mannitol is easily absorbed by people with healthy intestinal linings, whereas lactulose is a larger molecule, and thus is only slightly absorbed. A person is instructed to drink a solution containing both of these molecules, and then their urine is collected for six hours. The amount present in the urine reflects how much was absorbed by the body – a healthy test will display high levels of mannitol, and low levels of lactulose. If high levels of both are found, it indicates increased intestinal permeability. If low levels of both are found, it indicates general poor absorption of all nutrients (Wong, 2020).
It is important to note that this test is an indicator of small intestine permeability, and cannot definitively diagnose leaky gut with full certainty. Most physicians steer clear of this test, as they do not believe it is very reliable. Additionally, since increased intestinal permeability is a symptom of many other diseases, it should not be used to necessarily diagnose leaky gut syndrome, as this could prevent a patient from receiving treatment for a more serious condition they may have. Seeking the advice of a gastroenterologist is recommended, as they specialize in digestive health and the GI tract.
To date, there are no FDA-approved treatments available at this time for leaky gut, especially because it is not officially a diagnosable condition. Instead, the treatment recommendations a person is likely to receive from their doctor will instead be focused on the underlying condition they’ve diagnosed, which may include leaky gut as a symptom. For example, if you’ve been diagnosed with inflammatory bowel disease, the treatment will likely be anti-inflammatory drugs, immune system suppressors, antibiotics, pain relievers, and supplements to help the lining of your gut recover. If the diagnosis is irritable bowel syndrome, then anticholinergic medications, tricyclic antidepressants, antibiotics, or medications specifically for IBS may help reduce the symptoms.
If your doctor feels confident that you likely have leaky gut, they may recommend adjusting your diet to remove inflammatory foods that could impact gut flora, such as:
Additionally, the doctor (or a registered dietician) may also recommend a low FODMAP diet. Usually, this diet is recommended for people with IBS or even celiac disease, but it may help relieve some of the symptoms from leaky gut as well, especially since there is so much symptom overlap.
Creating a diet rich in foods that aid the growth of beneficial gut bacteria is important as well. Some great options are vegetables (and fermented vegetables), roots, fruit, sprouted seeds, fish, cultured dairy products (if no dairy sensitivities exist) and nuts (Raman, 2019).
Campos, M. 2017. Leaky gut: What is it, and what does it mean for you? https://www.health.harvard.edu/blog/leaky-gut-what-is-it-and-what-does-it-mean-for-you-2017092212451
Clapp, Megan. 2017. Gut microbiota’s effect on mental health: The gut-brain axis. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5641835/
Frothingham, S. 2019. How Long Does It Take to Heal a Leaky Gut? https://www.healthline.com/health/how-long-does-it-take-to-heal-leaky-gut – causes
Lee, S. 2015. Intestinal Permeability Regulation by Tight Junction: Implication on Inflammatory Bowel Diseases. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4316216/
Morris, G. et al. 2016. The Role of Microbiota and Intestinal Permeability in the Pathophysiology of Autoimmune and Neuroimmune Processes with an Emphasis on Inflammatory Bowel Disease Type 1 Diabetes and Chronic Fatigue Syndrome. https://www.eurekaselect.com/145540/article
Raman, R. 2019. The Leaky Gut Diet Plan: What to Eat, What to Avoid. https://www.healthline.com/nutrition/leaky-gut-diet
Wong, C. 2020. What Is Leaky Gut Syndrome (Intestinal Permeability)? https://www.verywellhealth.com/leaky-gut-syndromeintestinal-permeability-89258