If you've ever been on #GutTok, the popular corner of TikTok dedicated to gut health, chances are you've heard people talk about "leaky gut" or "leaky gut syndrome."

But what exactly is it?

Leaky gut refers to the concept of relative intestinal permeability, or the ability for things to move through the intestinal lining.

"Your intestines are part of your digestive system that is about 25 feet long, that has a strong protective lining inside it that prevents food, digestive juices and bacteria from leaking out," explains Dr. William Li, a physician and bestselling author of "Eat to Beat Your Diet: Burn Fat, Heal Your Metabolism, and Live Longer." "When that lining is damaged, these substances leak from inside the gut to its outside, like a punctured garden hose, and can cause a severe inflammatory response in your belly."

What causes leaky gut? 

Everyone's gut "leaks" to some degree, as the barrier is "not completely impenetrable (and isn't supposed to be!)," according to Harvard Health. This allows things like water and nutrients to pass through, but it can cause issues if the permeability increases. 

"Studies have shown that people who have certain chronic gastrointestinal diseases have leaky guts that let larger molecules through — potentially toxic ones," the Cleveland Clinic's website notes.

Leaky gut may be triggered by other gut health issues, Li says, including inflammatory bowel disease and celiac disease. It may also be associated with other autoimmune diseases, asthma, food allergies, medication overuse, chemotherapy or chronic stress.

"We know that the condition of having intestinal permeability or a 'leaky gut' is real, but we don't know that it's a disease in itself, or that it causes other diseases," the Cleveland Clinic says, but adds, "It's not currently a recognized medical diagnosis."

Leaky gut symptoms

Li says common feelings associated with leaky gut include:

• Indigestion
• Stomach pain
• Burning sensation
• Bloating
• Gassiness 

"The constant irritation from these symptoms can lead to fatigue and irritability," he says.

Of course, it is possible to have these symptoms without having a leaky gut, so it's important to discuss what you're experiencing with your doctor. 

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How to treat leaky gut

Because leaky gut is still not well understood, Li says there is no simple cure — but some interventions can be helpful, such as:

• Eating foods that foster gut health. A healthy, balanced diet can encourage a healthier microbiome or gut bacteria. 
• Avoiding foods that irritate your gut. 
• Adjusting lifestyle factors. Exercise, good quality sleep and lowering stress can all play a role in healing your gut health, Li says.

If you're dealing with leaky gut caused by a different gut issue, treating the underlying condition can also be beneficial.

"Specific treatments for (inflammatory bowel disease), celiac disease and others associated with intestinal permeability have been shown to repair the intestinal lining in those who were affected," the Cleveland Clinic says.