If you have been spending hours trying to figure out if you have leaky gut or not, then THIS is the ultimate guide for you! We’ll not only look at the top 3 tests to consider, but also the 10 main symptoms of leaky gut. Let’s go!
Last Updated: Nov 18, 2023
In this guide, you’ll discover…
It took me a long time to realize leaky gut was the culprit of my many health woes.
Which isn’t surprising.
After all, who’s walking around on a normal day thinking, “Hmmm, maybe my intestinal wall is hyperpermeable” (aka leaky gut).
But when I first suspected I had it, I did what everyone else would do…
…look for the best test for leaky gut and a list of the most common symptoms.
When I started researching all the different tests available and speaking to colleagues, I came across a variety of approaches to take.
Most were terrible in terms of scientific grounding and conclusiveness.
Thankfully with more and more research I eventually found a few worth considering. And I’ll run through the 3 most popular ones below.
Most interesting of all, I’ll run you through a free testing protocol for leaky gut – I found this approach to be hugely helpful.
Let’s dive in!
P.S. if you find yourself with signs of leaky gut, check out my free leaky gut guide here.
The lactulose and mannitol test acts as a very direct test for leaky gut by looking solely at how permeable/leaky the intestinal wall is.
Studies like this one have confirmed its efficacy, as they conclude “Evaluation of intestinal permeability in this way provides an objective means of diagnosing food allergy [issues]”. In other words, this test can act as a diagnostic for leaky gut, which can therefore identify food allergies.
How does the lactulose and mannitol test work?
Well, you simply consume 2 types of non-metabolized sugar, one with large molecules (lactulose) and one with small molecules (mannitol), and then your urine is analyzed to see which sugars passed through your system1.
If the lactulose (larger molecules) find their way into your urine, your gut may be considered overly permeable, ie leaky.
Given its specialist focus it is considered the #1 test for leaky gut.
If you are interested in getting this test, it’s quick and easy to order and – as you can see – non-invasive and very simple to do. Even more conveniently, it can be ordered straight to your home and is very affordable in terms of testing, with prices starting from around $179.
True Health Labs offers the lactulose mannitol test at this price (this is not an affiliate link – I just find it to be a truly great test).
This is the only real blood test for leaky gut syndrome and here’s how it works.
So, the main thing to know is that the cells of your intestinal lining are held together by tight junctions. Tight junctions can be thought of as gatekeepers, keeping the cells close together so that only the good stuff gets let in, and all of the larger particles and bad stuff, stays out.
The main thing to know here is that zonulin effects the gatekeepers of your gut lining (the tight junctions) in a negative way2.
Specifically, zonulin can work with other molecules to pry apart these tight junctions and change the size of the openings in your gut lining3. As such more zonulin means openings increase in size and the lining becomes more permeable / leaky.
Obviously we want some zonulin to ensure nutrients get through (and that’s why we have it). But too much and you can say hello to leaky gut!
This test is thus designed to see whether you have too much zonulin in your system and thus may have leaky gut4.
But arguably a more interesting question is: “What causes zonulin levels to rise in the first place?”. Because if we can answer that, we can fix the problem itself.
Well, gluten plays a big role in zonulin levels5, as does candida / yeast, harmful bacteria and parasites6. So keeping an eye on them is key.
But in certain people, eg celiacs, zonulin is released at higher levels in the presence of gluten compared to healthy people7.
Overall, this test is interesting, but unless your doctor or other healthcare professional orders it, it’s probably worth skipping.
I’ve had the great pleasure of putting more stool samples in test tubes than any person ever should. Sometimes I’ve felt like a fecal-crazed Heisenberg with my own spin off TV series…Breaking Biome.
Weird? Oh, most certainly.
So why on earth do I like putting stools in tubes so much?
Well, just like we get blood tests to see if there is something wrong with us, I like to get stool tests to see if there is something wrong with my gut health8.
You see, the poor scientists analyzing my stool sample (the real unsung heroes of society!) will perform microbiome testing to determine what’s going on inside the jungle of my gut.
Stool contains a lot of bacteria, and it provides a great reflection of what’s going on in the gut.
So, scientists can use my stool to look for bacteria (good and bad), viruses, bacteriophages, fungi, yeast, parasites and all sorts of other goodies that may be contributing to or associated with my intestinal permeability, aka leaky gut, with a particular focus on finding what potentially harmful organisms are present or otherwise out of balance9.
And just as importantly, they will analyze what nutrients and toxins these organisms are producing from the foods I eat.
This is the sort of information my doctor and I can then use to take action to fix my gut health or otherwise optimize it.
Historically, microbiome testing has been pretty useless in terms of takeaways
In fact, if you asked me whether it was worth doing only 2-3 years ago, I would have said heck no!
I remember when I got my first few tests it was more out of scientific wonder, than anything else.
My doctor and I would be sitting there pouring over the data and just looking at each other going…okay, so now what?
It may as well have been jibberish.
But things are changing – tests are becoming 10x more useful!
Some companies are actually starting to deliver plain English results and most of all, tell you what you should do with the results they find!
I mean, imagine receiving a letter in a language you couldn’t speak or understand – and now, finally having a translator convert it to plain English!
i.e. instead of just sending you a complex and bewildering list of strains in your gut, they are now sending you individualized recommendations and lifestyle tips to improve your gut health and thus intestinal permeability.
This changes everything.
Unfortunately, there are dozens of companies out there offering what they say are the ‘most advanced’ tests. But most are delivering nothing of the kind.
Ubiome and Viome are 2 interesting testing companies I’m keeping my eye on, because the data they produce is solid. However, the actionable takeaways they offer in the results they send back are still quite limited.
Thryve is doing interesting work too, but I feel their testing service is a loss leader for their follow up products. So I’m not totally sold on them.
So is microbiome testing really worth it?
I would say it is NOT worth getting if you are feeling pretty good these days thanks to eating the leaky gut diet and living the clean lifestyle. i.e. if it ain’t broke, there’s nothing to fix!
So if you’re one of my many readers who has managed to turn things around, then forget about it.
By contrast I would say it is worth trying if you…
- Have done the leaky gut diet for 30 days, but still aren’t feeling better. i.e. the test could help you pinpoint some specific-to-you food sensitivities that may be holding you back.
- Don’t have the time to do a 3-month elimination-reintroduction diet.
- Want to find out what foods you can eat more of and which ones to hold off on. e.g. maybe legumes are fine for you.
- Are interested to find out whether you have a specific bacteria or yeast overgrowth issue.
- Already have a condition and want more info / data points to help you and your doctor manage it better.
If you don’t like the idea of paying for expensive tests like those above, you can consider doing a simpler 2-pronged holistic test (with the supervision of your doctor of course).
I’ll run through how I have done this in the past
First, I compared my personal health history against all the signs of leaky gut.
After seeing I had several signs of digestive problems (food sensitivities, stomach pains, heartburn, brain fog, unexplained fatigue, IBS, and asthma), and previously suffered from other signs that indicated leaky gut (like eczema)10, I decided that there was ‘more probability of leaky gut than not’.
Given I had not been able to find any other reasoned diagnosis for my collection of symptoms, I was more than happy to finally have a working hypothesis.
Next I decided to embark on a 90-day leaky gut diet, paired with smart gut-supporting supplements like L-Glutamine, Digestive Enzymes and Probiotics (they are links to 3 articles on this site that explain how these 3 supplements can help).
I figured that if after 90 days the 7 signs I had of leaky gut were gone or severely diminished it was because my gut had healed (and was indeed originally ‘leaky’).
Within the first month of this protocol I already experienced a decrease or elimination of the majority of symptoms.
Stomach pains gone. Heartburn non-existent. Asthma 80% reduced. It was amazing!
And after the full 3 months I was in amazing health.
For example, I no longer carried antacids with me, rarely reached for my inhaler, woke up in the morning full of energy, worked all day with intense focus (and without coffee!), and I even noticed how much easier it was to gain lean muscle (probably because my body was able to absorb all the nutrition finally). Talk about a big difference!
Whilst I could not be 100% certain I had leaky gut, I can be certain that the leaky gut recovery protocol, which you can find in my free guide here, worked to fix my health problems. And for me that is all the proof I need.
Of course n=1.
In other words, this is but my own experience. Your results will differ, since everyone’s body is different.
But the great thing is that you have the power and you can start today!
What to consider doing today
- Check your personal health history against the 10 symptoms below
- Speak to your healthcare professional about doing a 90-day leaky gut protocol and see how you feel at the end. You should consult your doctor before undertaking such a protocol.
If you have leaky gut there is also a good chance you’ll be experiencing several of these symptoms.
e.g. at my worst I was enjoying food intolerances, SIBO, all the digestive problems below (the trio of fun times!), several of the skin related issues, brain fog and nutrient deficiencies.
So don’t get overwhelmed or feel worried, if you find yourself nodding to several of the symptoms/signs below.
1) Food allergies / intolerances
As we know food sensitivities may arise when undigested food particles or toxins in general cross the (leaky) gut barrier and into your bloodstream.
So what we’re saying is that to develop a food intolerance, having an overly permeable gut lining may just be a prerequisite11.
Basically here’s what happens: whole food particles aren’t meant to cross the gut barrier into your bloodstream. When they do, the body doesn’t recognize them – so, the immune system flares up in an attempt to defend your body against what it perceives as foreign invaders.
Well, we all know what it means when the immune system flares up – inflammation, inflammation, inflammation! And that’s accompanied by a large side of symptoms.
Unfortunately, it might continue doing this every time you eat certain foods, especially gluten and dairy12 (it is scared!).
And that’s the thing – foods you may have previously tolerated, can all of the sudden become intolerable, as the body is now fighting against them every time they show up.
Although you can do the elimination diet, like me, to see what foods cause you grief, there are certain foods that might only cause you subtle pain.
That’s where a food intolerance test comes into play. Without this test it can be quite difficult to identify exactly which foods are causing a reaction – and, you may very well keep eating them without even knowing they’re harming you!
This can lead to ongoing, low level systemic inflammation. i.e. your leaky gut will never completely heal.
The main test to consider is the IgG food allergy test13 (other two are IgA14 and IgM15)
Additionally, since you’re suspecting leaky gut may be part of your problem it is often worth getting a candida test as part of this allergy test since candida is associated with leaky gut bacteremia16.
All of this testing can be done from home with a simple dry blood collection.
These tests will then look to see if your body is producing high levels of antibodies in your blood.
Overall, this is an indirect blood test for leaky gut syndrome, so consider speaking to your doctor to see if it is worth taking (and paying for). Hint: these tests ain’t cheap!
2) Autoimmune conditions
For certain AI conditions like Celiac Disease17, there is a very strong link with leaky gut.
Whilst for other conditions (and AI related issues) like rheumatoid arthritis18 and Type 1 diabetes19, the link is still strong, however it is not entirely clear which one causes the other.
With a growing body of research demonstrating the link between leaky gut and AI conditions, it’s definitely worth thinking about gut health status if you currently suffer from an AI condition.
Everyone is different of course. That is why it is wise to consult with your doctor and see what sort of personal program you can create together.
3) Small Intestinal Bacterial Overgrowth (SIBO)
The term ‘bacteria’ historically had a bad rap – but, research has made it quite clear that bacteria can be our best friend! In fact gut flora accounts for much of our immunity20, like microscopic security guards protecting our body.
But, just as a couple of bank robbers can overpower all of the harmless workers and customers, bad bacteria, too, has the power to disrupt our entire digestive ecosystem and throw our gut out of balance. This can prevent good bacteria from doing their job and lead to digestive conditions such as leaky gut itself.
So a condition like small intestinal overgrowth (commonly shortened to SIBO)21 is a good (leading) indicator that you might be suffering from leaky gut22.
Thankfully, unlike leaky gut there is a simple breath test for SIBO23. It’s not simply, ‘does this person have halitosis?’, which is, the technical and fancy word for plain old bad breath?’.
Instead, it’s the same test used to check for IBD and other GI disorders24.
All you need to do is consume a sugar-based solution (lactulose again!) and then breathe into a test tube or balloon-style device. You can even do this at home and send the results in.
Basically what they’ll then look for is the level of certain gases like methane and hydrogen in your sample, which are produced by certain bacteria. Too high and you could have bacteria overgrowth in the small intestine, ie SIBO.
If you take this test make sure you avoid probiotics for 1 week prior (check with your doctor) and avoid alcohol, veg and fruit for 48 hours before the test. Avoiding these ensures bacteria measurements are accurate.
4) Inflammatory Bowel Disease, eg Crohn’s Disease, Ulcerative Colitis
The link here with leaky gut is quite clear – and as mentioned above, studies are increasingly revealing the growing link between leaky gut and autoimmune disorders such as IBD.
The generally accepted connection is that intestinal hyperpermeability starts, then it leads to the development of IBD25,26.
Said differently, if you have IBD, you likely have leaky gut.
There is no chicken and the egg problem here. Unsurprisingly then, there is also a strong connection between people who suffer with IBS and leaky gut27.
5) Digestive problems
I’m not just talking about diarrhea, constipation and heartburn/reflux/GERD here.
But also more innocent things like excessive gas, bloating and burping.
As someone who carried Zantac around with them full time from the age of 15 (!) I was able to tick a few of these boxes. But this prolonged medication use is not only abnormal, but it’s unhealthy!
And that’s just it – so many people nowadays experience recurring digestive symptoms that we simply try to normalize it and maybe throw some medication down so that we can move on with our lives.
But, I can tell you experiencing these symptoms on a regular basis is not normal. The gut is crying out for help.
So, if you find that after every meal you have to open the windows or get under the covers to keep your gas to yourself, or have to plan your outfits around the fact that your belly will undoubtedly double in size after dinner – that indicates digestive problems.
Thankfully since I started eating clean and supplementing smart I haven’t experienced any of these digestion problems. Not needing to worry about running out of Zantac after a big dinner out is fantastic!
6) Skin problems like eczema, acne, Rosacea, Hives, Psoriasis, rashes etc
It’s often forgotten that the skin is the largest organ we have, so if our skin is in poor health, it likely means that our body is not in balance and something needs to be fixed.
There is a long history of leaky gut leading to skin conditions such as eczema28. In other words, the connection is not new.
Probably most interesting is the speed at which these signs can disappear when you start following a proper leaky gut recovery protocol like this one.
7) Brain fog or general fatigue or chronic headaches
The gut and the brain are connected through the gut-brain axis – meaning, the health of your gut can impact the health of your brain and, vice versa. So, if one is in poor shape, it typically influences the other!
If your head is pounding or feeling cloudy, believe it or not, this is something that can indicate leaky gut, but only if you’re experiencing it despite sleeping and eating well.
Ie don’t use this to judge your chances of leaky gut if your overall health is in poor shape.
8) Mood swings and depression
Given that up to 95% of your serotonin is housed in your gut29, it is no wonder we call the gut the second brain.
As mentioned above, there’s a strong link between the gut and the brain – so it is plausible to think that a leaky gut, which causes inflammation and havoc in general down there, could play a large role in how you feel. In fact, some studies have shown that some depressed patients could have leaky gut30.
So, if you’re feeling low and can’t particularly pinpoint an event or reason, there’s a chance your gut health is out of whack and playing a bigger role in your mood than you think.
9) Allergies, eg seasonal, pet etc
Having sensitivities to cute little puppies is not a life I want to live!
Thankfully the connection with leaky gut is similar to food allergies, which means it can be fixed through sealing up the gut barrier and reinoculating your gut with probiotics31.
Say bye-bye to running from pets and say hello to petting them, as they should be.
10) Nutrient deficiencies
This one might perplex you somewhat.
So as we know leaky gut is a problem because it sees bigger particles pass through your gut lining that shouldn’t. But here’s the thing…
…leaky gut can also mess with your gut lining, or more specifically, your gut’s microvilli32, in such a way that whilst they let the big baddies through (eg gluten)33, they stop letting the small good guys through (eg nutrients).
Think of an automatic gate that’s malfunctioning. It’s not necessarily that it’s stuck open and everything is getting through – it may also be opening and closing at the wrong times, therefore letting some bad guys in and keeping some good guys out.
Over time, this can lead to nutrient malabsorption and vitamin & mineral deficiencies.
Worse yet, since the good guys aren’t getting through, there is no one there to detoxify all the antigens being produced by your enraged immune system! It’s a double whammy.
Thankfully there is a simple test you can do to see if you are nutrient deficient, and thus possibly suffering from leaky gut. It’s called an organic acid test.
You simply order a kit to your home, leave a urine sample and then post it back. But here’s the thing…the lab does not test your urine for nutrient levels themselves, but rather for the acid levels.
You see, high levels of acids – a byproduct of nutritional deficiency – will indicate much more accurately that your body is suffering malabsorption.
There are a few other signs of leaky gut to consider, eg autism34, obesity35 etc, but for me the link is not quite there yet. I won’t be shocked if and when the link is established though.
Instead of spending $100s, if not $1000s, on tests that will not necessarily give you a clear yes or no, you might want to consider simply speaking with your healthcare professional about starting a leaky gut recovery protocol today (here’s mine) if you have one or more of the 10 signs of leaky gut above.
A leaky gut recovery protocol is a safe, healthy and economical way to do right by your gut and both see and feel the difference you’re making for your body.
Once the 90-day protocol is complete, you can try a provocation diet* to see what foods you can and cannot tolerate (like I did).
*This simply means adding potentially bad foods back in that you restricted during the 90 days.
This entire process will allow you to give your gut the time, space and resources it needs to heal and, in the end, ensure you’re reintroducing the foods you love so that you don’t feel limited and like you’re stuck on a restrictive diet for the rest of your life.
So if you’re excited to start, then download my FREE Leaky Gut Recovery Protocol (PDF).
This is the EXACT process I used to say goodbye to leaky gut. And it includes instructions on what to do every step of the way. It is nice and simple too.
Happy reading!
References
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