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Leaky gut: Symptoms, causes & treatment

23 Feb 2022 • 4 min read

Leaky gut syndrome, also known as leaking gut syndrome, is still very much debated in the medical field, but doesn’t mean you shouldn’t know more!

Join us as we tell you all about leaky gut symptoms, leaky gut causes, and leaky gut treatments, along with everything else you might need to know about this divisive condition.

In this article, we will cover

  • The immune-gut link
  • What is a leaky gut?
  • What are the symptoms of a leaky gut?
  • What triggers a leaky gut?
  • Are there any conditions linked with leaky gut?
  • Are allergies and your gut linked?
  • Is there a leaky gut syndrome test?
  • How to fix a leaky gut
  • Leaky gut syndrome: Summary

The immune-gut link

More than 70% of your immune system is found in your gut, in the form of a type of lymph tissue called gut-associated lymphoid tissue (GALT).

Your gut’s role in immunity is complex.

You can see your gut as a sort of gatekeeper; it lets beneficial substances in and out but stops foreign bodies – such as bacteria, funguses, and viruses – from getting out through its lining.

What is a leaky gut?

Leaky gut, also often referred to as leaky gut syndrome or leaking gut, is when your gut lining allows partially digested food or toxins through into your bloodstream.1

Your gut is meant to be permeable up to a point, as it allows water and nutrients into your bloodstream after they have been broken down, crucial for providing the energy your body needs.

However, sometimes this goes wrong.

Proteins line the gut in a single layer and are meshed tightly to form barriers, especially in certain parts of the bowel.

If those links become too loose, unhelpful substances can leak into the bloodstream.

This is known as a ‘leaky gut’, but it’s a bit of a controversial topic.

What are the symptoms of a leaky gut?

9 symptoms of leaky gut syndrome may include:

  1. Bloating
  2. Confusion and difficulty concentrating
  3. Digestive issues, such as chronic diarrhoea or constipation
  4. Fatigue
  5. Headaches
  6. Inflammation
  7. Joint paint
  8. Nutritional deficiencies
  9. Skin problems, such as acne or rashes2

As there are so many potential symptoms, it can be different to narrow down whether the cause is leaky gut syndrome or if the leaky gut syndrome is simply a symptom of a more serious condition.

What triggers a leaky gut?

In the debate of what causes leaky gut, multiple potential triggers have been found, suggesting that leaky gut is triggered by a combination of dietary or lifestyle choices.

9 causes of leaky gut syndrome include

Read on to learn more about the causes of leaky gut syndrome.

  1. Too much sugar

A diet that’s high in sugar—especially one which has a high intake of fructose—is believed to damage your intestinal wall, reducing its effectiveness as a barrier to your bloodstream.3

  1. Excessive alcohol

As alcohol has been proven to reduce the levels of beneficial bacteria in your gut, it is also believed to increase the permeability of your intestinal wall, meaning that gaps may be more likely to appear.4

  1. Deficiencies in certain vitamins

Studies have shown that participants who had deficiencies of vitamin A, vitamin D, and zinc had an increased risk of high intestinal permeability and leaky gut.5

  1. An unhealthy gut

For a happy gut, we need to maintain a microbiome of beneficial bacteria, which can be managed by a balanced diet of prebiotic and probiotic foods and drinks.

When this balance is broken, it has been proven to negatively affect the barrier function of our intestinal wall.6

Handpicked content: Foods To Keep Your Gut Healthy

  1. Too much yeast in your gut

It is natural for yeast to be present in your gut, but too much of it can lead to leaky gut syndrome.7

To reduce the risk of this, try not to have too much sugar, yeast-based foods, white flour, or cheese.

  1. High levels of stress

Maintaining a high level of stress for a long period of time has been linked to a number of gastrointestinal conditions, including leaky gut syndrome.8

  1. Chronic inflammation

Chronic inflammation, especially inflammation that affects the intestinal tract over a long period of time, has been previously linked to leaky gut syndrome as it reduces the effectiveness of the gut’s barrier function.9

  1. Long-term usage of non-steroidal anti-inflammatory drugs (NSAIDs)

It has been found that taking NSAIDs—such as ibuprofen—regularly over a long duration can trigger leaky gut syndrome as it increases the permeability of your intestinal walls.10

  1. Coeliac disease

Celiac disease is an autoimmune disease that presents itself as an over-sensitivity to gluten.

One study found that coeliac patients who ingest gluten see a significantly increased intestinal permeability directly after consumption.11


These 9 things have been linked to increasing the likelihood of leaky gut syndrome:

  • Too much sugar
  • Excessive alcohol
  • Vitamin deficiencies
  • An unhealthy gut
  • Too much yeast in your gut
  • High levels of stress
  • Chronic inflammation
  • Long-term NSAIds, such as ibuprofen
  • Coeliac disease

Are there any conditions linked with leaky gut?

Studies have found a wider range of chronic conditions may be linked to leaky gut, increasing the risk of leaky gut syndrome by affecting intestinal permeability.

  1. Chronic Fatigue Syndrome

A 2016 study from Cornell University found that participants with chronic fatigue syndrome showed signed of inflammation in their bloodstream.

This was believed to be because of bacteria leaking through their intestinal wall.12

In addition, the bacteria present in their gut was different to that of participants without CFS.

  1. Children with eczema

Research has also shown that children with eczema may be at increased risk of leaky guts, likely due to a connection between the inflammatory qualities of this condition which may affect the effectiveness of the gut’s barrier.13

  1. Migraines

Scientists have found a relationship between migraines and gut disorders.

For example, those who suffer from IBS often experience regular migraines, and this is believed to be because the higher levels of negative substances leaking through the gut wall cause these headaches.14

  1. Histamine intolerance

A leaky gut is thought to be one of the underlying causes of an overload of histamine intolerance.

Histamine – a chemical released in an allergic reaction, which is also found in certain foods – can cause allergy-type symptoms including brain fog, headaches, eczema, and digestive problems when it’s released in large amounts.

A histamine overload can happen partly due to a lack of the enzyme DAO.

A small 2015 study found 70% of cases of histamine intolerance could be linked to DAO deficiency.

DAO mixes with food in the digestive tract where it breaks down histamines.

If you don’t have enough DAO, you could be left with high levels of histamine in your body, which is believed to contribute to gut leakiness.15

  1. Coeliac Disease

Although it is yet to be determined whether the intolerance to gluten causes the leaky gut syndrome or the leaky gut syndrome causes coeliac disease, there are multiple studies supporting the idea that those who suffer from one condition have a higher chance of suffering from the other.16

  1. Crohn’s Disease

Crohn’s is a chronic digestive disorder with symptoms of persistent inflammation of the intestinal tract, linked to an increased risk of intestinal permeability.17

Separate studies have also found that relatives of those with Crohn’s also show signs of increased intestinal permeability, suggesting a relationship between this condition and leaky gut.

  1. Irritable Bowel Syndrome

Irritable Bowel Syndrome (IBS) is a digestive condition that often shows itself in symptoms of diarrhoea and constipation.

High intestinal permeability is also seen in those with IBS, especially those who are prone to frequent diarrhoea.18

  1. Food Allergies

A number of studies have suggested food allergies are linked to a less effective intestinal barrier.19

The reason for this is believed to be that a leaky gut allows more food proteins through the intestinal wall, causing an immune response.

This immune response—called an anti-gen—is the basis of an allergic reaction to food.20

Is there a link between your allergies and your gut?

We know that allergies are caused by our immune system over-reacting, but new research shows our gut has an important role to play too.

Runny nose, itchy skin, bloating?

You might not immediately think your gut is linked to any allergies you have, but some research is now suggesting that a leaky gut may have a key role in causing allergies.


Leaky gut has been linked with a wide range of chronic conditions:

  • Chronic Fatigue Syndrome (CFS)
  • Eczema in children
  • Migraines
  • Histamine intolerance
  • Coeliac Disease
  • Chrohn’s Disease
  • Irritable Bowel Syndrome (IBS)
  • Studies have shown a potential relationship between your leaky gut and allergies

Is there a leaky gut syndrome test?

There are multiple leaky gut tests available, each taking a different route to understanding if you have leaking gut syndrome. A few of these include:

  1. Differential Sugar Test (Lactulose Test)

The differential sugar test checks for intestinal permeability.

After fasting overnight, you drink a sweet solution containing Lactulose, a type of sugar.

Over the following 6 hours your urine is collected and the amount of Lactulose in this urine is then tested.

As Lactulose is a larger sugar it is normally broken down by the body for energy, so if lactulose is found in your urine, this may be a sign that this sugar was released through the wall of your gut before it had been fully digested, therefore suggesting that you may have leaky gut syndrome.21

  1. Serum Zonulin Testing

The regulator protein, Zonulin, is almost like the bodyguard of the intestinal wall, allowing nutrients through the barrier by opening and closing the gaps as needed.

For this test, your blood is checked for the amount of Zonulin present.

If you’re showing high levels of Zonulin, it may mean that too much is being released in your gut, which increases your intestinal permeability and can represent leaky gut syndrome.22

  1. Intestinal Biopsy

An intestinal biopsy is the most invasive and expensive way of checking if you have leaky gut syndrome, so it is often reserved for research labs.

The way this test works is that a sample of intestinal tissue is removed and investigated to see how well molecules pass along or through its intestinal lining.

Depending on how easily these modules pass through, increased permeability can be proven, suggesting whether a person may have a leaky gut.

Curing leaky gut: How do you fix a leaky gut?

Whether or not a leaky gut can be fixed is debatable, considering experts are still undecided on leaky gut syndrome as a standalone condition or merely a result of other chronic afflictions.

However, there are still a few ways you can support your overall gut health, which may help to reduce leaking gut symptoms.

  1. Eat your way to better gut health

There may be no such thing as a “leaky gut diet,” but creating a diet that supports healthy gut is a step in the right direction.

Recommendations include:

  • Eat more high-fibre prebiotics: Bananas, whole grains, and colourful fruits and vegetables feed your beneficial bacteria and support a healthy gut.

The fibre in fruit and vegetables is very important as it feeds good gut bacteria. These good bacteria help you release important vitamins and minerals from food which strengthen your barriers to the environment, including the lining of the lungs and gut.

  • Eat more probiotics: Probiotics for leaky gut may included fermented foods, whereby beneficial bacteria is abundant and creates a thriving microbiome, such as kefir, kimchi, sauerkraut, and miso.
  • Reduce animal products: A plant-based diet has been linked to a healthier gut, so it might be worth decreasing your intake of meat and dairy.
  • Avoid added sugar: Sugar and artificial sweeteners have been proven to reduce the effectiveness of our good bacteria, so try to be mindful.

Handpicked content: How to have a happy gut

  1. Making a few lifestyle changes

Supporting a healthy gut may mean you need to create a few new habits in your day-to-day life, such as:

  • Regular exercise
  • Getting enough sleep
  • Managing your stress levels
  • Limiting your intake of antibiotics and NSAIDs—remember that NSAIDs such as ibuprofen have been linked to an increase of symptoms in leaky gut syndrome

Handpicked content: Why You Should Exercise for a Healthy Gut

  1. Supplements for leaky gut

  • L-glutamine for leaky gut: Glutamine is an amino acid that has many benefits for our bodies, one of which is supporting intestinal health. It is found in raw, leafy vegetables (like spinach), beans and legumes, animal proteins, and dairy products, but l-glutamine supplements are also available if you need helping getting more glutamine into your diet.
  • Probiotics for leaky gut: Probiotics are friendly bacteria which help to build and strengthen your microbiome, where a variety of bacteria work together to support your body’s processes. If struggling to get enough probiotics via your diet, probiotic supplements (in both tablet and powder form) can help.

Although supplements for gut health may support you in creating a leaky gut syndrome diet, it is always recommended to build a diverse microbiome with a healthy, balanced intake before reaching for supplements.

Handpicked content: What Are Probiotics: Types & Foods


  • Diet: Increasing your intake of prebiotics and probiotics with a variety of fruit, vegetables, and fermented dishes are linked to a healthy gut
  • Lifestyle: Making a few changes in your daily life—such as exercise and more sleep—may improve your gut health and gradually help you to manage your leaky gut
  • Supplements for leaky gut: L-glutamine or probiotic supplements support gut health and may aid in reducing the symptoms of leaky gut

Leaky gut syndrome: Summary

Leaky gut syndrome is still widely debated in medicine as it has many different symptoms and is linked to a number of chronic conditions.

As this is the case, it is difficult to confirm whether leaky gut causes these conditions or is caused by them.

Regardless, leaky gut symptoms may be reduced by improving your lifestyle and diet, including fruits, vegetables, probiotics, exercise and sleep.  

The advice in this article is for information only and should not replace medical care. Please check with your GP or healthcare professional before trying any supplements, treatments or remedies. Food supplements must not be used as a substitute for a varied and balanced diet and a healthy lifestyle.

Last updated: 23 February 2022



Author: Bhupesh PanchalSenior Regulatory Affairs Associate

Joined Holland & Barrett: Apr 2019

Masters Degree in Toxicology and BSc Hons in Medical Biochemistry

Bhupesh started his career as a Clinical Toxicologist for Public Health England, advising healthcare professionals all around the country on how to manage clinical cases of adverse exposure to supplements, pharmaceuticals, cosmetics, industrial chemicals and agricultural products.

After 7 years in this role and a further year working as a drug safety officer in the pharmaceutical industry, Bhupesh joined Holland & Barrett as a Senior Regulatory Affairs Associate in 2019.

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