Healing the gut

The term "leaky gut" has gained mainstream attention over the past few years. You may have heard it referred to as increased intestinal permeability.

Leaky gut syndrome is not a recognized medical diagnosis in conventional Western medicine. Increased intestinal permeability is a known condition, and what is not yet understood is whether it's a symptom or a cause of chronic disease.

What is a leaky gut?

The intestinal walls contain a tight epithelial lining that controls what passes through into your bloodstream.

Normal intestinal tight junctions are selectively permeable, meaning that digested food and nutrients can pass, but pathogens and partially digested food cannot.

A leaky gut means that toxins, partially digested food, and certain bacteria can pass through, potentially causing inflammation, disruption of a healthy gut microbiome, and digestive problems.

Increased intestinal permeability is associated with a variety of mostly gut-related disorders, from inflammatory bowel disease (IBD), celiac disease, and irritable bowel syndrome (IBS), to non-gut disorders like type 1 diabetes. (1)

Leaky gut syndrome as its own independent disease is sometimes claimed to be the root cause behind a number of symptoms from insomnia to depression, but there is not yet conclusive evidence in human studies that it is a distinct disease entity.

Symptoms of leaky gut

Symptoms vary and depend on which condition they are associated with (as mentioned above, they are typically found with IBS, IBD, and celiac disease). They can include:

• Abdominal pain

• Diarrhea or constipation

• Nausea

• Vomiting

• Fatigue

• Weight loss

• Cramping

• Fever

• Bloody or mucus-containing stools

• Excess gas

What may cause increased intestinal permeability

While the exact cause of increased intestinal permeability is still under investigation, research has identified a link to a protein called zonulin.

Zonulin helps regulate the tight junctions of the gut. Studies show that higher zonulin levels are associated with loosened tight junctions and increased permeability of the gut. (2)

Both gluten and some bacteria have been shown to impact zonulin levels in certain individuals. (3) In people with celiac disease or non-celiac gluten sensitivity, gluten consumption may increase intestinal permeability. (4) In other individuals, gluten has not been shown to increase intestinal permeability.

Gut dysbiosis is another factor. At any given time there are thousands of different bacterial species living in the gut. When that balance shifts so that potentially harmful bacteria outnumber beneficial bacteria, it can contribute to increased intestinal permeability. (5)

Long-term use of NSAIDs, such as aspirin and ibuprofen, may increase intestinal permeability. (6)

How to support gut health

Because increased intestinal permeability is usually a symptom rather than a standalone diagnosis, treatment depends on the underlying condition. That said, there are evidence-informed steps you can take to support gut health, digestion, and microbial balance:

1. Include probiotic foods. Fermented and cultured foods such as kefir, sauerkraut, kimchi, and some fermented teas can introduce beneficial bacteria that help rebalance the gut microbiome.

2. Feed beneficial bacteria. Prebiotic fibers — the carbohydrates that beneficial bacteria feed on — are found in many plant foods, including bananas, broccoli, berries, and Jerusalem artichokes.

3. Consider reputable food-sensitivity testing with clinical guidance. If you suspect food reactions, discuss testing options with your healthcare provider. If you use an at-home test, choose one that is clinically validated and follow up with a clinician so results are interpreted correctly.

4. Limit commonly inflammatory foods while you explore causes. Foods that commonly trigger inflammation or intolerance for some people include gluten, alcohol, dairy, highly processed foods, and excess sugar. If you suspect IBS, researching and trialing a low-FODMAP approach under guidance may help identify triggers.

5. Reduce frequent NSAID use when possible. Since long-term NSAID use appears linked to increased intestinal permeability, discuss alternatives and appropriate dosing with your clinician.

6. Support recovery thoughtfully. Certain nutrients may help support overall immune and metabolic health. Talk with a healthcare provider about whether zinc, vitamin D, or a B complex is appropriate for you, and use supplements only as recommended.

7. Quit smoking. Tobacco use is associated with inflammatory changes in the gut and a higher risk of bowel disorders. Stopping smoking can help reduce that risk. (8)

8. Manage stress. Chronic stress can influence the gut-brain axis and microbial balance. Practices such as regular physical activity, sleep hygiene, meditation, or counseling can help. (9)

When to seek medical help

If you suspect increased intestinal permeability and you are experiencing persistent discomfort, pain, or worrying symptoms, see a doctor. Increased intestinal permeability is often a symptom of an underlying condition that may require specific diagnosis and treatment.

Disclaimer

The statements in this article have not been evaluated by the Food and Drug Administration. The products mentioned are not intended to diagnose, treat, cure, or prevent any disease. Please check with a doctor before starting any new supplement and to ensure the advice in this article is right for you.

Resources

(1) Matthew A. Odenwald and Jerrold R. Turner. Intestinal permeability defects: Is it time to treat? https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3758766/
(2) Alessio Fasano. Zonulin and its regulation of intestinal barrier function: the biological door to inflammation, autoimmunity, and cancer. https://pubmed.ncbi.nlm.nih.gov/21248165/
(3) Ramzi El Asmar; Pinaki Panigrahi; Penelope Bamford; Irene Berti; Tarcisio Not; Giovanni V Coppa; Carlo Catassi; Alessio Fasano. Host-dependent zonulin secretion causes the impairment of the small intestine barrier function after bacterial exposure. https://pubmed.ncbi.nlm.nih.gov/12404235/
(4) Justin Hollon; Elaine Leonard Puppa; Bruce Greenwald; Eric Goldberg; Anthony Guerrerio; Alessio Fasano. Effect of gliadin on permeability of intestinal biopsy explants from celiac disease patients and patients with non-celiac gluten sensitivity. https://pubmed.ncbi.nlm.nih.gov/25734566/
(5) Sophie Leclercq; Sébastien Matamoros; Patrice D Cani; Audrey M Neyrinck; François Jamar; Peter Stärkel; Karen Windey; Valentina Tremaroli; Fredrik Bäckhed; Kristin Verbeke; Philippe de Timary; Nathalie M Delzenne. Intestinal permeability, gut-bacterial dysbiosis, and behavioral markers of alcohol-dependence severity. https://pubmed.ncbi.nlm.nih.gov/25288760/
(6) Ingvar Bjarnason; Ken Takeuchi. Intestinal permeability in the pathogenesis of NSAID-induced enteropathy. https://pubmed.ncbi.nlm.nih.gov/19148789/
(7) N J Mantis; N Rol; B Corthésy. Secretory IgA's complex roles in immunity and mucosal homeostasis in the gut. https://www.nature.com/articles/mi201141
(8) Luc Biedermann; Jonas Zeitz; Jessica Mwinyi; Eveline Sutter-Minder; Ateequr Rehman; Stephan J Ott; Claudia Steurer-Stey; Anja Frei; Pascal Frei; Michael Scharl; Martin J Loessner; Stephan R Vavricka; Michael Fried; Stefan Schreiber; Markus Schuppler; Gerhard Rogler. Smoking cessation induces profound changes in the composition of the intestinal microbiota in humans. https://pubmed.ncbi.nlm.nih.gov/23516617/
(9) Jane A Foster; Linda Rinaman; John F Cryan. Stress & the gut-brain axis: Regulation by the microbiome. https://pubmed.ncbi.nlm.nih.gov/29276734/