Leaky gut (intestinal permeability)
Reviewed by Dr. Nikita Dinger, Founder & CEO, BioMeBar. Last reviewed 7 October 2026.
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What it is
“Leaky gut” is a popular phrase, not a diagnosis your doctor will write on a report. The scientific term is increased intestinal permeability. The lining of the intestine is a single layer of cells joined by tight junctions, and it lets nutrients through while keeping most unwanted material out. Permeability describes how easily things cross that barrier, and it rises and falls in everyday life, with exercise, alcohol, infections and certain medicines.
Research confirms that higher permeability is measurable and is seen in conditions such as coeliac disease, inflammatory bowel disease and some cases of IBS. What is not established is that it is the root cause of the wide range of problems it is sometimes blamed for, from fatigue to autoimmune disease. Our page on the gut barrier goes into the biology.
It helps to approach this popular phrase the way you would any trending health term: with interest, and with a request for evidence. The underlying physiology of the gut barrier is genuinely fascinating and increasingly well understood. The claims made for commercial products built around it often run well ahead of that science.
Common symptoms
There is no symptom list specific to intestinal permeability. People who search for it usually have one or more of the following, all of which have many possible causes:
- Bloating, gas, loose stools or cramps
- Reactions that seem to follow certain foods
- Fatigue, brain fog or achy joints
- Skin flare-ups
Because these symptoms are so general, they need a proper medical look before they are put down to the gut barrier.
If you have been told online that your tiredness or skin trouble is due to a porous gut lining, it is fair to ask what else was ruled out. Anaemia, thyroid disease, low vitamin D and poor sleep are far more common explanations and are easy to check.
How gut bacteria may be involved
Gut bacteria ferment fibre into short-chain fatty acids, notably butyrate, which is the preferred fuel for cells lining the colon and is associated with barrier maintenance in laboratory studies. Some bacteria also help regulate the mucus layer that sits over the lining. A less diverse community, or one low in butyrate producers, is associated with higher permeability in some studies, although those findings come mostly from observation and animal work.
Other influences on permeability include heavy alcohol use, anti-inflammatory painkillers like ibuprofen taken regularly, severe stress, intense endurance exercise in heat, and gut infections. Commercial permeability tests, including zonulin stool or blood tests, have not been validated for use in routine care, so we do not rely on them.
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Diet and everyday habits
Advice online can be extreme. A balanced approach to gut barrier support is mostly everyday good food. See the leaky gut diet page for a practical outline.
- Fibre variety feeds the bacteria that make butyrate: dals, rajma, chana, oats, ragi, jowar, bajra, bananas that are just ripe, cooked and cooled rice or potato
- Fermented foods such as curd, chaas, idli and dosa fit in naturally
- Limit alcohol and avoid regular use of NSAID painkillers unless prescribed
- Keep sleep regular, manage stress, and avoid crash diets or long juice fasts
- Do not remove gluten, dairy or whole food groups on the strength of an online test
A realistic week might include dal or sprouts daily, two or three different whole grains, a few portions of vegetables of different colours, some fruit, a serving of curd or chaas, and a small handful of nuts or seeds. Nothing here is exotic, and none of it needs a special product.
When to see a doctor first
- Blood in the stool, persistent diarrhoea or unexplained weight loss
- Anaemia, fever, or night-time symptoms
- Persistent joint swelling, rashes or other signs that could point to an autoimmune condition
- Symptoms after eating gluten, with a family history of coeliac disease
- Chronic fatigue that is not improving, which may need blood tests for thyroid, iron, B12 and vitamin D
How BioMeBar approaches it
We keep to what the science supports. We ask about your symptoms and diet, review your gut profile and match a personalised synbiotic, with food and lifestyle guidance centred on fibre diversity and routine. Check-ins let us see whether anything changes for you.
We do not diagnose, treat or cure intestinal permeability or any condition linked to it, and we do not sell permeability tests.
Where intestinal permeability is raised by something like coeliac disease or IBD, the primary step is the medical condition itself. Our guidance sits beside that, not ahead of it.
Common questions
Can intestinal permeability be tested?
Research tools exist, such as sugar absorption tests, but they are not part of routine clinical care. Consumer zonulin tests have not been shown to be reliable.
Does gluten damage the gut barrier in everyone?
In people with coeliac disease, gluten drives gut lining damage. In others the evidence is much less clear, and wheat can bother some people for other reasons.
Do supplements like glutamine or collagen repair the gut lining?
Early research is limited, and human evidence for these products in people with ordinary symptoms is not strong. Food-first measures are the safer starting place.
Sources
- ISAPP consensus statement on the definition of prebiotics (2017)
- Rome IV diagnostic criteria for functional gastrointestinal disorders (Rome Foundation)
- ACG Clinical Guideline: Diagnosis and Management of Celiac Disease (2023)
- ICMR-NIN Dietary Guidelines for Indians
Talk to us
If you would like to know whether BioMeBar can support you, message us on WhatsApp. Tell us your symptoms and your pincode and we will take it from there. Not sure where to start? Take the free gut assessment, which takes about three minutes.
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BioMeBar provides nutrition and gut health guidance and does not replace medical care. See a doctor for severe, persistent or worrying symptoms.