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  • Marie Belzile-Davidson, MS, RDN, LD

What the heck is leaky gut?

Harvard Health calls it a “medical mystery” and “mysterious ailment.” It’s been linked to everything from gut troubles, to autoimmune diseases, and even mental health concerns.

I’m talking about “leaky gut” or “intestinal permeability.” Have you heard of it before?

While it may not yet be recognized as a condition by many in the established medical community, there is growing research that suggests leaky gut is associated with many health conditions.

What exactly is leaky gut? We’ll walk you through the basics and help you better understand if you may have it, what may cause it, and what you can do about it!

What is leaky gut anyway?

Your gut, also known as your gastrointestinal system, is more than just a 30-foot-long muscular tube that starts at your mouth and ends with you going to the bathroom. It’s a vast and complex system with many functions: it breaks food down into smaller digestible bits, keeps this food moving through the gastrointestinal tract, and skillfully absorbs water and nutrients all while keeping out harmful substances. More and more research shows that these essential gut functions are interconnected throughout your body—to everything from your heart to your brain.

Your gastrointestinal tract is lined with millions of cells, all side-by-side in a single layer. If this layer were spread out flat, it would cover 400 square meters of surface area! These cells act as gatekeepers - they allow certain things into the rest of our body, like nutrients from the foods and beverages we consume, while keeping other substances out. This selectivity is only possible if the cells are working properly and are physically joined together very tightly/have “tight junctions.”

Leaky gut happens when the tight junctions aren’t so tight anymore. The cellular barrier is irritated and weakened, allowing tiny holes to appear. These gaps allow things that would normally stay out of the bloodstream (and the rest of our body) to make their way through. This can include things like food particles, waste products, and bacteria. When these get into the bloodstream, our immune system is triggered to start fighting them, similarly to how it starts fighting the cold virus and causes inflammation. This immune reaction is normal and helps keep you healthy.

Do you have a leaky gut?

The symptoms of leaky gut are similar to those of other digestive conditions like inflammatory bowel disease (IBD), celiac disease, and irritable bowel syndrome (IBS). Symptoms can include diarrhea, constipation, cramps, bloating, food sensitivities, or nutrient deficiencies.

Remember that leaky gut means food particles, toxins, and bacteria that should normally be eliminated can end up in your bloodstream. This allows these substances to travel throughout your body, which means symptoms of leaky gut can really appear anywhere!

Studies show that leaky gut may feel like fatigue, headaches, confusion, difficulty concentrating, joint pain, or skin problems (e.g., acne, rashes, eczema). Leaky gut is also linked with diabetes, polycystic ovarian syndrome, liver disease, chronic fatigue syndrome, and autoimmune diseases such as lupus and multiple sclerosis. There may even be links to anxiety and depression. It is important to note that many of these gut and non-gut symptoms and conditions are linked to chronic inflammation, but more research is needed to better understand how they are all connected.

Even if you have some of these symptoms, the reality is that it’s very difficult to diagnose a leaky gut, let alone determine how “leaky” it is. This means that while there is some testing that can be done, there isn’t a reliable diagnostic test available just yet. Therefore, it’s difficult to say whether certain symptoms are from leaky gut, or whether leaky gut is a symptom of another issue.

What causes leaky gut?

It’s not 100 percent clear what causes those bonds/tight junctions to loosen and create tiny gaps in the gut barrier. In fact, we’re just starting to understand how the gut barrier functions! The good news is, there is a lot of ongoing research in this area. Here’s a bit of what we do know so far:

The genes you inherit from your parents may play a role in the development of leaky gut. Leaky gut may also be caused by certain medications or gut infections. Leaky gut is also linked to eating a diet that is low in gut-friendly fiber (adults should aim for 25-30 g of fiber per day). It can also be from consuming too much added sugar and saturated fat. Leaky gut may even result from stress or an imbalance in the diversity and quantity of your friendly gut microbes.

Also, as we age, our cells can get damaged more easily and heal more slowly. This includes the cells that line our gut. Overall, this can leave us more susceptible to the loosening of those tight junctions.

So what can you do if you suspect you have leaky gut?

As with any issue, it is best to address the root cause. If you suspect you have leaky gut, reach out to a registered dietitian that is familiar with this condition. They can help you determine what may have caused your leaky gut in the first place, to best address it!

One way to approach a suspected leaky gut is to address inflammation and eat a more gut-friendly diet. This means reducing excessive alcohol and processed foods that tend to be high in fat, sugar, and/or artificial sweeteners. Instead, enjoy more foods rich in gut-friendly probiotics along with options that contain prebiotics, like fiber, which are food for your friendly gut microbes. These include

  • yogurt or kefir

  • fermented foods (e.g., kimchi, sauerkraut, and miso)

  • fruits and vegetables (e.g., berries, oranges, broccoli, carrots, and zucchini)

  • nuts and seeds (e.g., walnuts, cashews, and chia seeds)

  • Whole grains (e.g., oats, brown rice, and quinoa)

It’s also a good idea to avoid foods that you’re allergic or sensitive to. For example, if you have diagnosed celiac disease, you want to be sure to stay away from gluten, as exposing your gut to it can cause a large inflammatory response.

Pro Tip: If you’re going to proactively increase your fiber intake, do it over several days or weeks because a sudden increase in fiber can cause gas, bloating, and other gut discomfort. If you have IBS, talk to your doctor or a registered dietitian to determine which fibers may worsen your condition vs. which ones are recommended.

Additionally, regular exercise can help your digestive system. This can even be as simple as a 15 or 20-minute walk after you eat, to help you digest your food. Don’t forget the importance of stress management, quality sleep, and not smoking!

If you plan on making changes to your diet and lifestyle, consider keeping a journal to help see if the changes are helping your symptoms

So what are the leaky gut takeaways?

A leaky gut is associated with both gut and non-gut symptoms. It’s an inflammatory condition that has been linked to metabolic disorders, autoimmune conditions, and even mental health.

At this time, there is no good diagnostic test that can determine with absolute certainty whether or not you have leaky gut. Remember though, this is a relatively new area of research so there is more exciting and emerging information to come on this topic!

In the meantime, if you have symptoms that hint at leaky gut, you can move toward a more gut-friendly diet. Try cutting down on processed foods, alcohol, and other potentially inflammatory foods like gluten and dairy. Replace these foods and beverages with ones higher in gut-friendy probiotics and fiber. Don’t forget that regular exercise, stress management, and quality sleep are great lifestyle strategies for your gut and the rest of your body too!

If leaky gut or other inflammatory symptoms are bothering you, complete our 1:1 Dietitian Nutrition Coaching Application today-Gretchen will reach out to schedule your complimentary call after you complete the coaching application!


Harvard Health. (2018). Putting a stop to leaky gut. Retrieved from

Harvard Health. (2018). Putting a stop to leaky gut: What can you do about this mysterious ailment? Retrieved from

Leech, B., Schloss, J. & Steel, J. (2019). Association between increased intestinal permeability and disease: A systematic review. Advances in Integrative Medicine. 6(1), 23-34.

Mayo Clinic. (2016). Food sensitivities may affect gut barrier function. Retrieved from

Medical News Today. (2019). What to know about leaky gut syndrome. Retrieved from

Medical News Today. (2019). What is the best diet for leaky gut syndrome? Retrieved from

Medscape. (2019). Is 'Leaky Gut' the Root of All Ills? Retrieved from

Mu, Q., Kirby, J., Reilly, C. M., & Luo, X. M. (2017). Leaky Gut As a Danger Signal for Autoimmune Diseases. Frontiers in immunology, 8, 598. doi:10.3389/fimmu.2017.00598

National Institutes of Health News in Health. (2017, May). Keeping Your Gut in Check. Retrieved from

Obrenovich M. (2018). Leaky Gut, Leaky Brain? Microorganisms, 6(4), 107. doi:10.3390/microorganisms6040107

US Department of Health and Human Services and US Department of Agriculture. (2015). Dietary Guidelines for Americans 2015-2020, eighth edition. Appendix 7. Nutritional Goals for Age-Sex Groups Based on Dietary Reference Intakes and Dietary Guidelines Recommendations. Retrieved from


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