Leaky Gut Digestive Symptoms: Bloating, IBS, SIBO and More

Written by Dr. Ryan Kneessi, ND

Quick answer: Leaky gut has been associated with many digestive symptoms, including bloating, gas, diarrhea, constipation, abdominal pain, heartburn and food sensitivities. Increased permeability has also been studied in IBS, IBD, SIBO and celiac disease. Because these symptoms have many causes, it’s important to see your doctor first to rule out other diagnoses.

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Key takeaways

Digestive symptoms have many possible causes, so it is best to rule out other conditions with your doctor first.

Diarrhea, constipation, bloating, gas and pain can reflect changes in the microbiome and gut lining.

IBS, inflammatory bowel disease, celiac disease and SIBO are among the conditions linked with increased permeability.

See your doctor first

Digestive symptoms have many possible causes. Talk with your doctor to rule out other conditions. Background: introduction to leaky gut.

Common digestive symptoms

Diarrhea or constipation

Changes in the microbiome and gut lining can shift bowel habits either way.

Bloating and gas

Dysbiosis, an imbalance of gut bacteria, is a common cause. See dysbiosis.

Abdominal pain

Inflammation and the gut-brain connection can both contribute to pain.

Food sensitivities

When the barrier is compromised, the immune system may react to food particles.

Indigestion and heartburn

Inflammation and microbiome changes can interfere with normal digestion.

Conditions linked with increased permeability

Conditions linked with increased permeability include irritable bowel syndrome (IBS), inflammatory bowel disease (Crohn’s and ulcerative colitis), and small intestinal bacterial overgrowth (SIBO), as well as celiac disease and stomach ulcers.

Digestive health and healthy aging

Digestive function and the gut microbiome tend to change with age. Addressing symptoms early can support nutrient absorption and help lower inflammation.

Next steps

Track symptoms and possible triggers
Learn the body-wide signs too (see systemic symptoms)
Ask about testing options (see diagnosis)

When to see a naturopathic doctor

It may be time to see a naturopathic doctor if you have ongoing bloating, gas, diarrhea or constipation, or food reactions that seem to be multiplying. The same is true if you have fatigue, skin flares or joint aches alongside gut symptoms, or if you want a personalized gut plan instead of guessing.

See a medical provider promptly for blood in your stool, black stools, unexplained weight loss, persistent vomiting, severe abdominal pain, fever, or trouble swallowing.

What the research shows

Some of the clearest evidence on the gut barrier comes from a 2019 randomized, double-blind trial by Zhou and colleagues. It enrolled adults who developed diarrhea-predominant IBS with increased intestinal permeability after a gut infection. Participants took 5 g of glutamine three times a day or a placebo for 8 weeks, and 54 and 52 people finished each group. A meaningful drop in IBS symptom scores occurred in 79.6% of the glutamine group compared with 5.8% on placebo, and the lactulose-to-mannitol permeability ratio fell from 0.11 to 0.05. This was a single trial in one specific group of people, and the authors called for larger studies to confirm it.

Bovine colostrum has also been studied. A 2024 meta-analysis by Hajihashemi and colleagues pooled 10 randomized trials in athletes and patients. Colostrum lowered two urine-based measures of intestinal permeability, the lactulose-to-rhamnose ratio and the lactulose-to-mannitol ratio, but it did not change blood I-FABP, a marker of gut-lining injury. The trials varied widely in dose, duration and quality, so the authors said more research is needed.

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Questions to bring to your clinician

These questions can help you get the most out of your next visit.

Which tests would help us sort out the cause of my digestive symptoms?

Which of my bloating or bowel symptoms might be connected to my gut lining?

Would a breath or stool test help sort out what is going on?

Which food changes would be worth trying first for my symptoms?

Frequently asked questions

What are the first signs of leaky gut?

Common signs include bloating, gas, irregular bowel habits and food sensitivities, though these have many causes.

Is IBS the same as leaky gut?

No, but increased permeability has been found in some people with IBS.

Can leaky gut cause heartburn?

Inflammation may contribute, but heartburn has many causes.

When should I see a doctor?

For persistent symptoms or any red flags such as bleeding or weight loss.

Sources

Zhou Q, Verne ML, Fields JZ, et al. Randomised placebo-controlled trial of dietary glutamine supplements for postinfectious irritable bowel syndrome. Gut 2019. PMID: 30108163. https://pubmed.ncbi.nlm.nih.gov/30108163/
Hajihashemi P, Haghighatdoost F, Kassaian N, et al. Bovine Colostrum in Increased Intestinal Permeability in Healthy Athletes and Patients: A Meta-Analysis of Randomized Clinical Trials. Dig Dis Sci 2024. PMID: 38361147. https://pubmed.ncbi.nlm.nih.gov/38361147/
Camilleri M. Leaky gut: mechanisms, measurement and clinical implications in humans. Gut 2019. PMID: 31076401. https://pmc.ncbi.nlm.nih.gov/articles/PMC6790068/
O’Toole PW, Jeffery IB. Gut microbiota and aging. Science 2015. PMID: 26785481. https://pubmed.ncbi.nlm.nih.gov/26785481/
Dunlop SP, et al. Abnormal intestinal permeability in subgroups of diarrhea-predominant irritable bowel syndromes. Am J Gastroenterol 2006. PMID: 16771951. https://pubmed.ncbi.nlm.nih.gov/16771951/
MedlinePlus: Celiac Disease

This article is for educational purposes only and is not medical advice. It does not replace an individual evaluation. Talk with your healthcare provider before starting supplements or changing medications, especially if you are pregnant, nursing, or managing a health condition.