But “leaky gut” is a physiological process, not a formal medical diagnosis. We all experience increased permeability from time to time. It’s something that fluctuates constantly because of factors such as stress, infections and the food we eat.

Think of changes in permeability as a clue that something else may be going on. Studies have found that a growing number of diseases — inflammatory bowel disease, Parkinson’s disease, obesity, Type I diabetes, celiac disease and irritable bowel syndrome, to name a few — are associated with increased intestinal permeability. We’re still learning about these relationships. It’s not always clear if changes in permeability precede the diseases they’re associated with and what effect they’re having.

But the data is especially compelling in one area — liver disease. Research has found that consuming a high-fat diet or more alcohol can increase intestinal permeability, allowing bacterial toxins to slip past our gut lining and reach the liver, where they cause small amounts of inflammation. Over time, these small inflammatory events add up to problems such as fatty liver, which is on the rise, affecting 1 in 5 Americans.

Can you fix a ‘leaky gut’?

Many people on social media claim you can “cure” a leaky gut with probiotics, digestive enzymes or other supplements. These claims are not supported by scientific evidence. Instead, here are the five important recommendations I tell my patients who are worried about increased intestinal permeability. These well-studied interventions improve the integrity of your gut lining and have proven benefits for your overall health:

• Cut down on ultra-processed and high-fat foods. Eating a typical Western diet has been shown to induce more than double the amount of bacterial toxins in the blood, which can occur with elevated intestinal permeability. Studies have also found that emulsifiers, a common food additive to prolong shelf life, and artificial sweeteners in ultra-processed foods compromise the gut barrier. Not coincidentally, ultra-processed food consumption is linked to symptoms such as chronic abdominal pain and constipation often seen in irritable bowel syndrome.
• Reduce stress. Psychological stress increases intestinal permeability through the effects of the hormone cortisol (raise your hand if you’ve ever felt sick to your stomach before a big test). In an oft-cited study from Belgium, the stress experienced by university students who had to give a public speech to graduate generated significant increases in intestinal permeability.
• Minimize or stop alcohol use. Recent data has suggested that there is probably no “healthy” or safe amount of alcohol use in general, and this aligns with the data on alcohol’s effect on increasing intestinal permeability established over the last 30 years.
• Increase fiber in your diet. The fiber we eat gets fermented by our gut microbiota, which then produce beneficial short-chain fatty acids such as butyrate. These can fortify our intestinal lining and are associated with reduced inflammation.
• Avoid NSAIDs. Nonsteroidal anti-inflammatory drugs such as ibuprofen have been long known to damage our intestinal lining. When possible, substitute acetaminophen for chronic pain and preventive medication alternatives for migraines if you find yourself reaching for high NSAID doses for several days.

How do you tell if you have a ‘leaky gut’?

My patients often ask me how to check if they have a leaky gut. There are some sophisticated tests we do in the laboratory to measure intestinal permeability — such as using specialized devices called Ussing chambers involving biopsies taken during an endoscopy. These kinds of tests are not available in a standard doctor’s office, and I would be wary of any third-party company offering unvalidated testing.

To me, treating the many diseases and symptoms associated with altered intestinal permeability is most relevant. For instance, a 2021 study published in Gastroenterology found that certain patients with chronic abdominal pain and higher permeability improved after four weeks of treatment with a proton pump inhibitor. Others with food sensitivities may benefit from working with a registered dietitian to identify particular triggers. These possibilities should be thoroughly evaluated by a physician familiar with the science.

What I want my patients to know

Some doctors may tell you that leaky gut is not a real thing because they’re wary of all the misinformation peddled around it on social media. Neurogastroenterologists like me study intestinal physiology in depth, and I can assure you that changes in permeability are real.

But I worry that people are getting so caught up in the claims surrounding leaky gut that they may miss diagnosing an underlying disease. For example, people with celiac disease often have bowel trouble and brain fog — this should be assessed by a physician and treated accordingly. Feeling sluggish all the time could be because of iron deficiency anemia, and constipation and bloating may be related to hypothyroidism or irritable bowel syndrome. If you’re suffering, we need to methodically examine the whole picture — and not leave it simply at “leaky gut” — to get you feeling your best.