What Causes Leaky Gut and How to Heal It From the Inside Out

Mara Santilli
April 30, 2019

Leaky gut syndrome is becoming more common due to modern diets, medications, and chronic stress. And it turns out that gut health and immune response are more connected than you may have realized.

If you have sudden-onset food intolerances, GI tract issues, skin problems, brain fog , or were recently diagnosed with an autoimmune disease , there’s a chance that something else called leaky gut syndrome is going on. Leaky gut where the walls of the intestines start to loosen and holes form.

Molecules such as bacteria, toxins, or even certain food particles can leak outward from the intestines, through the gut lining into the intestines, or into the thin gut walls and cause confusion to the immune system . Read on to understand what it means to have intestinal permeability and how you can be kinder to your gut.

What is leaky gut, and what are the symptoms?

Leaky gut, also known by its scientific name, intestinal permeability, is the inflammation and weakening of the gut barrier, or the lining of the intestines. “Just like the skin, the gut barrier is an interface to the outside world, except it’s only one cell thick, rather than seven cells, as in the skin,” explains Zandra Palma, MD, a former physician at Parsley Health New York. The gut barrier’s membrane acts kind of like a gate, so that tiny molecules of nutrients, like vitamins, electrolytes, and even water, can travel in, out, and even between adjacent cells.

“But sometimes, the gates can get stuck open, and stitches between the cells can break,” says Dr. Palma. When this happens, higher amounts of a protein called zonulin, which is supposed to regulate the opening and closing of these “gates” can be measured and more molecules are able to move across the gut barrier, allowing it to access the immune tissue in the gut wall and cause inflammation.

When the gut barrier receives mass molecules that are not necessarily supposed to enter the gut, the immune system (80 percent of which exists in the gut, Dr. Palma notes) gets confused and begins to react negatively as it would with an allergic reaction, often by creating inflammation inside the gut. “The immune system thinks it’s under attack and can be sensitized to your own tissues, or foods that you may eat all the time,” says Dr. Palma. Now that the gut is more permeable, it’s potentially keeping good nutrients out and locking bad ones in, completely changing the gut makeup that your body is used to

That’s why symptoms of leaky gut may manifest themselves like allergies would: with eczema or dermatitis (and sometimes, but not always, gut symptoms—anything from increased gas and diarrhea to nausea). Because the gut and brain are connected through a series of nerves, mental health symptoms are also common with leaky gut, including anxiety , depression, brain fog , and severe fatigue .

One of the major tell-tale signs of it, though, explains Dr. Palma, is a new diagnosis of a food intolerance like gluten , or an autoimmune disease, such as rheumatoid arthritis, inflammatory bowel disease, or even lupus. These new reactions suggest that the immune system may suddenly be misfiring to target foods you once had no problem digesting, making them a common indication of intestinal permeability.

What causes leaky gut?

Some people may be genetically predisposed to gut barrier issues, or it can develop out of the blue, from something like excess chemicals in food, says Dr. Palma.

Much of what’s present in our food can be harmful to the gut barrier. One of the main causes of leaky gut is gluten: Studies have identified gluten as a culprit in increasing zonulin, the protein that contributes to holes in the gut membrane. Chemicals we’re exposed to through our food, like herbicides and pesticides, may also damage the gut barrier, says Dr. Palma.

Alcohol and drugs (even over-the-counter pain reducers and birth control , which affects the kind of bacteria in the gut) could also contribute to permeability in the gut, Dr. Palma says—so it can be helpful to limit them if not medically necessary.

Excess stress doesn’t help either. Not only does the microbiome play a role in regulating stress and anxiety-like behaviors , but similarly, high stress levels can lead to an unhealthy gut ecosystem and even actively compromise the intestinal barrier.

If your main symptoms are in the GI tract, there’s a chance that there’s an imbalance in your gut microbiome, which feeds the gut barrier and keeps its “gates” bound together. Not having enough good bacteria in your gut could be the problem that is causing these other gut issues, Dr. Palma points out.

How is leaky gut diagnosed?

Doctors can order a test that measures the levels of the molecule zonulin in the gut, but these tests can be extensive and costly. Dr. Palma notes that by paying strict attention to new food sensitivities or adverse reactions to foods that patients have previously been able to enjoy, testing is sometimes not needed to diagnose leaky gut. “Also, if you have a micronutrients test and are low on different nutritional markers, even macronutrients like protein, that’s a good indicator of leaky gut,” Dr. Palma says.

The connection between leaky gut and chronic disease

Studies showing leaky gut as direct cause of chronic diseases are limited, however increased intestinal permeability has been associated with several chronic diseases like celiac disease and gluten intolerance. Certain issues may also lead to intestinal permeability. “You may have a disrupted microbiome, parasite, excess bacterial growth in the small intestine, or a fungus in the GI tract—all of those issues may cause leaky gut,” Dr. Palma adds.

Why gut barrier health matters

“We evolve to be in constant communication with our environment through this barrier, because we have those gated channels within the cells of our GI tract,” says Dr. Palma. The gut barrier is a major part of the immune system, allowing molecules to enter and exit the gut and warding off the molecules that shouldn’t be entering. It protects your interior from the outside world, including harmful food sensitivities, autoimmune diseases, and even mental health issues, so it’s a huge factor in regulating our full-body wellness.

How to heal leaky gut

Work toward a heavily plant-based diet.

If you’re experiencing leaky gut, Dr. Palma suggests a leaky gut diet that’s fiber -filled and plant-based to decrease inflammation and irritation from gluten and other sugars. Meat and fish are fine to consume, but focus on gluten-free grains, vegetables and fruits, nuts, seeds, and healthy fats (bring on the avocado). Plus, the prebiotics found in high-fiber whole foods like asparagus and whole-grain oats are crucial to feeding the probiotic bacteria in the gut microbiome and keeping it healthy.

Try anti-inflammatory supplements.

To repair your gut barrier, there are plenty of vitamins and supplements you can choose from, says Dr. Palma. L-glutamine is commonly used in treating leaky gut. Licorice root and Omega 3- heavy cod liver oil, which is high in Vitamins A and D too, have anti-inflammatory benefits to tame the inflammation in the gut barrier.

High-quality medical-grade herbs such as slippery elm and cat’s claw can also help leaky gut (and other inflammatory bowel diseases) by soothing the gut lining .

Manage your stress through mind-body practices.

Stress-relieving practices like breathwork, a strategic form of deep breathing , can not only benefit your mental health, but it has also been found to lessen the immune system’s inflammatory response to toxins, especially in the gut. “This may be a way to change how the immune system enacts and reacts—you can imagine that extending to stress relief and resilience, both of which do affect the immune system,” Dr. Palma says. Any mind-body practice of your choice (yoga, meditation , or even acupuncture) can be beneficial to calming stress and keeping the gut happier in the long run.

Mara Santilli

Mara is a freelance journalist whose print and digital work has appeared in Shape, Brit+Co, Marie Claire, Prevention, and other wellness outlets.

Most recently, she was a member of the founding team of Bumble Mag, a branded content project for Bumble at Hearst Corporation. She enjoys covering everything from women's health topics and politics to travel. She has a degree in Communications as well as Italian Studies from Fordham University.

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