Leaky Gut and Intestinal Permeability: How to Support the Gut Barrier

“Leaky gut” is a popular term for increased intestinal permeability—a real biological phenomenon in which the intestinal barrier allows more material to pass between cells than usual. What is less clear is the idea of “leaky gut syndrome” as a single diagnosis that explains a broad list of symptoms such as fatigue, brain fog, skin problems, food reactions, and digestive complaints.

What Is Intestinal Permeability?

The intestinal lining is not supposed to be completely impermeable. It selectively absorbs nutrients while helping keep microbes and larger molecules in the gut lumen. Tight junction proteins help regulate what passes between intestinal cells.

Increased intestinal permeability has been documented in some conditions, including celiac disease, inflammatory bowel disease, infections, and critical illness. It has also been studied in IBS and metabolic disease. But increased permeability is usually considered one part of a larger disease process, not a stand-alone explanation for every symptom.

Is “Leaky Gut Syndrome” a Medical Diagnosis?

Intestinal permeability is a real part of gut physiology, and supporting the intestinal barrier can be clinically relevant—especially when conditions such as celiac disease, IBD, infection, or IBS are present. The most useful approach is to connect barrier support to the underlying condition rather than treating “leaky gut” as a one-size-fits-all diagnosis.

What Can Affect the Gut Barrier?

• Celiac disease and inflammatory bowel disease: both can directly affect intestinal integrity.
• Gastrointestinal infections: some infections can temporarily disrupt barrier function.
• Alcohol: heavy or chronic intake can increase intestinal permeability.
• NSAID use: medications such as ibuprofen and naproxen can affect the gastrointestinal lining in some people.
• Diet, stress, and the microbiome: these may influence barrier function, but their effects vary and are not equivalent to a diagnosis.

What Should You Eat for Gut-Barrier Health?

There is no validated “leaky gut diet.” A better goal is to support overall gastrointestinal health while treating any diagnosed condition.

• Eat a varied, nutrient-dense diet that includes vegetables, fruit, legumes, whole grains, nuts, seeds, and adequate protein as tolerated.
• Include fiber gradually when appropriate. Fiber supports bowel regularity, microbial fermentation, and short-chain fatty acid production; the best amount is the one your gut tolerates well.
• Include fermented foods if you tolerate them. Yogurt, kefir, kimchi, sauerkraut, and similar foods can be valuable additions to a diverse gut-supportive diet.
• Limit excessive alcohol and highly restrictive eating patterns.

If IBS is part of the picture, our low-FODMAP diet guide explains when a short, structured dietary trial may be appropriate.

Do You Need to Avoid Gluten or Dairy?

Not automatically. Gluten should be strictly avoided in celiac disease, and dairy may need adjustment in lactose intolerance or milk allergy. But routinely removing gluten and dairy for “leaky gut” without a clear reason can make the diet more restrictive without solving the actual problem.

What About Supplements for Gut-Barrier Support?

Several supplements are being studied for gut-barrier support, and some may be useful in selected situations. The best choice depends on the underlying condition, symptoms, and overall nutrition plan.

Probiotics

Some probiotic strains have evidence for specific gastrointestinal conditions, but effects are strain-specific. A generic “high-potency probiotic” cannot be assumed to repair intestinal permeability or help every person.

L-Glutamine

Glutamine is an important fuel source for intestinal cells and has been studied in several clinical settings. Small trials suggest possible benefits in selected patients, but evidence is not strong enough to recommend glutamine as a universal treatment for “leaky gut.”

Collagen and Bone Broth

Collagen provides amino acids, but there is not good clinical evidence that collagen supplements or bone broth specifically “seal” or regenerate the intestinal lining in otherwise healthy adults.

Digestive Enzymes

Digestive enzymes are useful when there is a specific indication—such as pancreatic enzyme insufficiency or lactase deficiency. They should not automatically be used as a general gut-repair supplement.

How Is Increased Intestinal Permeability Tested?

Research tools such as lactulose-mannitol testing and other permeability assays exist, but they are not routinely used to diagnose a broad “leaky gut syndrome.” Commercial biomarker panels should be interpreted cautiously because clinical thresholds and treatment implications are not standardized.

If you have persistent digestive symptoms, the more useful question is often whether you need evaluation for celiac disease, inflammatory bowel disease, infection, IBS, SIBO in the right context, pancreatic insufficiency, medication effects, or another established condition.

A Better 3-Step Approach

1. Identify the actual problem. Start with symptoms, history, appropriate medical evaluation, and evidence-based testing.
2. Treat the diagnosed condition. The plan for celiac disease, IBD, IBS, infection, or lactose intolerance is not the same.
3. Support recovery without unnecessary restriction. Use adequate nutrition, fiber as tolerated, sleep, exercise, and stress management while reassessing symptoms.

When to Seek Medical Evaluation

Seek medical care for blood in the stool, unexplained weight loss, persistent vomiting, anemia, fever, severe or worsening abdominal pain, new symptoms after age 50, nocturnal symptoms, or a strong family history of inflammatory bowel disease, celiac disease, or colorectal cancer.

If you need help organizing digestive symptoms, diet, and appropriate testing, learn more about our digestive and GI services and functional testing approach.

Frequently Asked Questions

Can you heal a leaky gut?

Barrier function can improve when the underlying cause improves. But there is no single protocol proven to “heal leaky gut” in everyone.

Does bone broth repair the gut lining?

Bone broth can be a nutritious food, but there is no strong clinical evidence that it specifically repairs intestinal permeability.

Are food sensitivities caused by leaky gut?

That causal claim is not established. Food allergies, intolerances, celiac disease, IBS triggers, and other adverse food reactions have different mechanisms and should not be lumped together.

References

1. Camilleri M. Leaky gut: mechanisms, measurement and clinical implications in humans. Gut. 2019;68(8):1516-1526. PubMed.
2. Bischoff SC, Barbara G, Buurman W, et al. Intestinal permeability—a new target for disease prevention and therapy. BMC Gastroenterology. 2014;14:189. PubMed.
3. Lacy BE, Pimentel M, Brenner DM, et al. ACG Clinical Guideline: Management of Irritable Bowel Syndrome. Am J Gastroenterol. 2021. PubMed.