Everything You Need To Know About Leaky Gut

The emergence of leaky gut syndrome over the past decade has lead to hundreds of supplements, plans and products being targeted towards healing a leaky gut but what actually is a leaky gut, is this condition real and if so, what can we do about it? Buckle in because this is the only article you need to read, it’s long but I promise it is worth the read. 

Alright, first up, ‘leaky gut’ actually isn’t a medical term, in the medical world the correct term is intestinal permeability, the term leaky gut or leaky gut syndrome has been made up by the wellness industry and marketing experts because, you know, it’s easier to say, understand and more sexy and sellable than the medical term intestinal permeability. You are likely conditioned to hearing the term leaky gut now though so for that reason, I am going to use this term throughout the article, keep in mind part of me cringes a little each time I write it #nerdalert 

One thing to point out before we begin is that the research in the area of leaky gut is really only just emerging and we do not know for certain everything there is to know. Many studies are in this area are conducted in vitro (in test tubes - not humans), or in mice. Human data in this area is only just beginning to emerge so anyone that tells you they know for certain how to accurately diagnose or treat leaky gut is straight up lying because we just aren’t at that point. 

The Truth: Leaky gut is a made up term, the correct term being intestinal permeability. Research in the field is in its early days an no one can say for certain how to diagnose, treat or even understand leaky gut.

What is Leaky Gut?

The lining of our intestines is made up of cells that are bound together by tight junctions. These tight junctions when functioning normally control what passes from the intestines into the blood stream. The main function of this intestinal barrier is to regulate the absorption of nutrients, electrolytes and water into the blood stream and prevent the entry of pathogenic microorganisms, toxic substances and larger particles into the blood stream. 

In the case of leaky gut, these tight junctions are compromised which can allow larger particles and substances to cross the intestinal lining and enter the blood stream. This can in turn promote inflammation by activating the immune system.


Leaky gut is not a condition, disease or syndrome, it is a sign and symptom that something is occurring in the body that is causing these tight junctions to become more permeable. Essentially leaky gut is caused by something else and is considered a symptom of another condition rather than a syndrome itself. 

The Truth:  Leaky gut occurs when the intestinal barrier is compromised and allows larger particles to pass into the blood stream. It is not a condition in itself, rather is a symptom of something else. 

What causes the gut to become leaky?

Doctor Google or your instagram wellness influencer is probably going to tell you leaky gut is caused by consuming too many grains, gluten, sugar, dairy, soy or something of the likes. I’ve even heard tap water being blamed! In reality though, there are some medications and medical conditions as well as lifestyle factors that can contribute to the leakiness of the gut but also we are still learning more here, we don’t definitively know what causes it in all situations. Some of the things we do know contribute to increase leakiness include:

  • Diseases that damage the intestines like coeliac disease 

  • Inflammatory Bowel Disease (Crohn’s and Ulcerative Colitis)

  • Excessive alcohol intake 

  • Overuse of NSAIDS

  • Infections 

  • Chemotherapy 

  • Dysbiosis (poor balance of gut bacteria)

  • Chronic or early life stress 

The Truth: Grains, dairy, sugar or soy are not the cause of a leaky gut, there are several medications, medical conditions and some lifestyle factors which can influence the permeability of the gut lining. 

How to Test for leaky gut?

According to gastroenterologists and researchers in the field there are no reliable or accurate tests to be able to determine if someone has a leaky gut. However this doesn’t stop a number of tests being used in the wellness industry. 

Often proponents of leaky gut syndrome will encourage you to take an intestinal permeability test which measures lactulose and mannitol in the urine which will help them to ‘diagnose’ your leaky gut. Now while this test is sometimes used in the research and can be a marker of impermeability it is not overly accurate or reliable but also we need to question what we do with the results of this test. Let’s say you spend $ getting the test done, now what? Even if it were accurate, does it dictate what you do next? 

As I mentioned earlier leaky gut is usually a symptom of something so it is like testing for nausea. Okay cool, we know you have nausea, now what? We actually need to work out what is causing it and what to do about it. So the test doesn’t actually give us any useful data to do something about it. 

IgG food intolerance tests are another common test which many people are instructed to take when trying to diagnose leaky gut. Unfortunately these food intolerance tests are completely (and I mean COMPLETELY) inaccurate. I’ve written a whole article on them, click here to have a read of that.

The third test often recommended for leaky gut is a stool or microbiome analysis test. These tests will show you the different types of bacteria in your gut. The problem with tests like this is that we actually don’t know what a healthy microbiome looks like! What we do know is that a healthy microbiome is a diverse one (aka lots of different types of bacteria), but we don’t know specifically what it looks like. 

So while these tests might be able to show you that you have low diversity in your gut, the way to fix a low diversity of you microbiome is to include a wide variety of plant based foods and plenty of dietary fibre. Now yes of course you can spend $400 on a test to tell you your microbiome diversity is low and may potentially contribute to a ‘leaky’ gut but the solution is to increase your plant based foods, your variety in your diet and your fibre. So sure if you want to spend $400 to be told to do this but the other option is you could simply just increase your plant diversity in your diet without spending the money (remember there is no harm in eating more plant based foods!). 

The Truth: We don’t have a single accurate method to test for a leaky gut. When spending money on tests we also need to question what will the results of this test actually mean for the next steps, if a test isn’t informing an accurate next step that couldn’t be done otherwise, then the test is a waste of money. 

How to ‘heal’ leaky gut?

Proponents of leaky gut syndrome will typically sell you a product or service that claims to heal your leaky gut, restore the intestinal lining and free you from the disease (remember it isn’t a disease). Now hopefully by this stage you are beginning to question everything you’ve seen but at the end of the day we still have a problem, what can we do about it. 

How can we actually fix leakiness? Well this is where we need to go back to the underlying reason for intestinal permeability. Is it gluten in coeliac disease, excessive alcohol consumption, inflammatory bowel disease or dysbiosis that is causing this leakiness of the gut? This is where your doctor or digestive dietitian is going to be able to help you. Below are a few things you can do to get to the bottom of this.

  1. Visit your GP to test for underlying conditions like coeliac disease, or IBD and manage appropriately 

  2. Look at medications which can impact the gut and discuss with your pharmacist and GP what options are available 

  3. Modify lifestyle factors like smoking, excessive alcohol consumption and stress that impact the gut 

  4. Eat a diet rich in dietary fibre with a wide variety of plant types which will feed your microbiome leading to a diverse, healthy microbiome 

  5. Include fermented foods like yoghurts, kefir, kimchi on a regular basis to give you extra assistance in building a diverse microbiome  

The Truth: The best way to treat a leaky gut is to address the underlying cause of the leaky gut by addressing any medical conditions like coeliac disease, inflammatory bowel diseases or infections, modifying lifestyle factors to promote good gut health and eating a diet which supports good gut health 

(FYI - I’ve done a sample meal plan which provides you with meal and snack ideas and recipes which promote good gut health here) 

What about diets and supplements?

This is where the marketing world enters. Of course if there is the potential to sell you a diet, a product a program or a supplement which will fix all your problems, of course the diet industry is onto it. 

I have seen a lot of BS when it comes to healing leaky gut and this includes things like collagen, bone broth, eliminating fruit, dairy, gluten, sugar, fibre, you name it some one has probably said it. 

In reality, there is no evidence to support any of this. When it comes to diet as I mentioned above the best diet to assist with leaky gut is one which is high in fibre and includes a wide variety of plants and fermented foods. Now in the case of Irritable Bowel Syndrome (different to IBD) a low FODMAP diet may temporarily be useful for symptom relief, however there is no evidence it will assist in leaky gut. Elimination diets of any sense have no been shown to be effective in leakiness of the gut except where medically required like gluten in coeliac disease or non-coeliac gluten sensitivity.

When it comes to supplements again, we do not have any human data to show any supplements will restore the integrity of the gut lining. The most commonly quoted supplement for this purpose is glutamine which is often used intravenously in IBD but when it comes to oral supplementation we don’t have any human studies to show it has a benefit.

The Truth: The diet industry and wellness influencers and quick to sell fads, supplements, diets and detoxes there is very little data to support the use of any of this. The best thing you can do is eat to support a healthy and diverse gut microbiome but including a wide variety of plants and fibre and fermented foods. 

What to do if you think you have leaky gut?

Regardless of whether leaky gut is a real syndrome or not, the symptoms you may be experiencing are in fact very real. Common complaints by people who believe they are experiencing leaky gut syndrome include:

  • Diarrhoea

  • Constipation

  • Abdominal pain 

  • Bloating

  • Gas and wind

  • Headaches

  • Brain fog

  • Fatigue 

  • Skin rashes 

Like I mentioned these things can all be very real but area also related to many, many conditions like coeliac disease, IBS, IBD, food allergies and intolerances, or even chronic stress. 

If you are experiencing symptoms like this a good starting point is your GP or a dietitian specialising in digestive diseases.

The Truth: If you are experiencing symptoms of GI distress it is important to check in with your medical practitioner to rule out serious digestive conditions, after which working with a digestive/gastro dietitian you can identify the next steps that are tailored to your specific underlying causes.

I understand some GP’s and Dietitians don’t have a complete understanding of digestive conditions and for this reason I am working on providing you with as much information on this as possible. 

If you have been struggling with receiving accurate information please make sure you are signed up to my email list as I will be keeping you updated on all things digestive health!