IBS & Leaky Gut Syndrome: How are they Different?


You may have heard of the term “leaky gut” and wondered what it is? A digestive issue with unknown causes, it has been suggested by some that a leaky gut is responsible for creating many other issues, similar to irritable bowel syndrome (IBS). However, the jury is still out on whether this should be a recognized condition, with doctors disagreeing on whether it is an issue at all, and whether it does have a connection to other disorders. So what constitutes a supposedly leaky gut (3,4)? 


What is it?

While irritable bowel syndrome (IBS) is a disorder of the gut-brain axis that causes stomach pain, irregular bowel movements (in form or frequency), and can greatly reduce the quality of life, a leaky gut is increased chronic permeability of the intestinal lining. The walls of the intestines are already meant to be somewhat permeable so that things like nutrients and healthy bacteria can pass through, but also act as barriers to keep out harmful substances and pathogens to maintain gut health. When these barriers are too permeable and the tight junctions between cells are slightly gapped or leaky, it allows the passage of more particles, possibly including harmful ones, triggering the body’s inflammation response (3,4). 

Leaky gut and its possible association with multiple conditions are being investigated, such as GI infections like salmonella or gastroenteritis, liver disease, food intolerance, chronic fatigue syndrome, and IBS (although it’s been debated, there have not been enough studies on leaky gut to say it is an issue for IBS sufferers at all). It’s a feature of Celiac disease as well as inflammatory bowel disease (IBD), but studies are not certain whether it may be a contributing factor in the development of IBD, or a byproduct (3). 


Both irritable bowel syndrome (IBS) and leaky gut disrupt the functioning of the digestive tract, and it is not known what causes either one. The delicate balance of gut bacteria (microbiota) is a large factor in both conditions, and because of this, some practitioners may recommend trying a clinically guided, tailored probiotics and prebiotics approach. High-fat foods and alcohol can impact gut function and should be consumed in moderation (3).



IBS is a recognized disorder and has a fixed set of criteria to diagnose it. Leaky gut, on the other hand, is associated with many other diseases, disorders, and situations, and does not have a specific set of diagnostic criteria, so it can not be diagnosed in the way that IBS can. The symptoms of leaky gut are also not as consistent as IBS, and they can come from multiple other issues. It is suspected by some researchers that inflammation could make gut permeability worse,  but inflammation can come from multiple sources (2,3).


Are they linked?

It’s unlikely that everyone with IBS has a leaky gut, but for people who exhibit other symptoms such as having other autoimmune diseases, joint pain, fatigue, allergies, or eczema, in addition to traditional IBS symptoms, the possibility is being investigated. It’s still unknown whether leaky gut plays any role in IBS, and more research on this is underway (2,4).


Can it be tested?

There are a few methods of testing leaky gut, although testing is quite limited without consistent results and cannot offer a diagnosis. One method is the lactulose/ mannitol test which measures the ability of sugar molecules to pass through the intestinal wall. There is also labwork that can examine lipopolysaccharides and zonulin in the body. These are molecules that should remain within the intestinal walls, but for those with a leaky gut, they can enter the bloodstream and can trigger an immune response. These methods are, however, predominantly used in research, are quantitative instead of diagnostic, and are not used by most doctors. Researchers are still in the process of developing more reliable methods of testing (2,3).


How can it be remedied?

There are no clear remedies that are supported by scientific research, aside from treating the underlying cause. Drinking too much alcohol or excessive use of NSAIDs (non-steroidal anti-inflammatory drugs like aspirin and ibuprofen) can irritate the intestinal lining and potentially affect barrier function. Dietary management doesn’t offer a clear solution, either. If you suspect you may have a leaky gut, avoid foods that trigger symptoms, and if you have food allergies be sure to avoid the allergens altogether. Celiac patients and those with gluten sensitivity should eat a lifelong gluten-free diet, but there is no conclusive research that suggests this is necessary for all people who have increased gut permeability, such as other IBD sufferers. Since IBD is an autoimmune disease there is a risk of increased intestinal permeability. There is a possibility that a low FODMAP diet could be beneficial with symptom management for some people, although the research is still inconclusive.  There have been positive studies done on mice that show that it could be of benefit, but as of yet, there is no conclusion on whether or not it’s useful for humans with gut permeability issues (3,4). 



If you’re exhibiting some symptoms of leaky gut and are concerned you may have it, talk it over with your doctor. Whether you do have issues with gut permeability or not, it’s recommended for most people with gut conditions to eat a balanced diet including a variety of plants, as well as to avoid excessive stress which will help you to keep a balance of healthy bacteria and to aid gut health.



Tamara Duker Freuman, “What is Leaky Gut Syndrome?,” fodmapeveryday.com, FODMAP Everyday, January 13, 2020, https://www.fodmapeveryday.com/what-is-leaky-gut-syndrome/.

Jodi Garlick, “Intro to Leaky Gut,” fodmapeveryday.com, FODMAP Everyday, September 14, 2021, https://www.fodmapeveryday.com/intro-leaky-gut/.

Amanda Gaukroker, “Leaky Gut vs. IBS: What’s the Difference and How Do I Know If I Have Either One?,” fodmapchallenge.com, The Fodmap Challenge, June 8, 2020, https://fodmapchallenge.com/leaky-gut-vs-ibs/.

Lyndal McNamara, “Gut permeability and IBS — do I really have a leaky gut?,” monashfodmap.com, Monash University, March 5, 2019, https://www.monashfodmap.com/blog/gut-permeability-ibs-do-i-really-have-leaky-gut/.