What is leaky Gut?
Leaky gut also known as intestinal permeability, where the single-thickness cells of the gastrointestinal tract move slightly apart and stay apart for extended periods. These ‘tight junctions’ are usually pulled together by tight bonds that act a little like a shoe lace. As well as in between the cells we also know, due to research by Dr Alessio Fasano, that there is leakiness through the cells and this can potentially lead to normal gut bacteria and toxins to cross into the bloodstream and create an immune response.
It is now known, thanks to ongoing, extensive research by Dr Fasano and his team, that gluten, a molecule within wheat, activates the amino acid Zonulin within the cellular tight junctions of the GI tract, causing them to widen and thus become more permeable, or ‘leaky’. For this reason, many practitioners will recommend eliminating gluten from your diet in the short term, while your gut heals and improves.
The symptoms of leaky gut are often hard to differentiate from other complex multifaceted conditions It rarely stands alone but makes up part of a comprehensive health picture that can lead to a variety of symptoms, such as:
- Bloating
- Flatulence
- Cramps
- Food allergies/sensitivities
- Joint aches and pains
- Sleep issues
- Depression
- Skin issues
- Brain fog
- Fatigue
Additionally, ‘leaky gut’ is known to play a part in immune dysregulation, inflammation, autoimmune disease and other chronic health conditions.
Possible contributory Factors
- Underlying chronic conditions such as Crohn’s, diabetes or coeliac disease
- SIBO – Small Intestine bacterial overgrowth – up to 50% of people with SIBO have increased intestinal permeability
- SIFO – Small intestinal fungal overgrowth
- Regular use of NSAIDs (non-steroidal anti-inflammatory drugs), PPIs (protein pump inhibitors) and similar medications.
- Regular use of antibiotics, which over time can disrupt the gut microbiome.
- Chronic stress – meditation can help.
- Excessive sugar intake, which can harm the barrier function of the intestinal wall.
- Excessive alcohol intake.
- Nutritional deficiencies, particularly in vitamins A and D, and zinc.
- Chronic inflammation.
- Poor gut health and/or poor digestive function
- Yeast overgrowth and/or Candida.
Treatment
There are a few steps to treating leaky gut
Step 1 – They key question to ask if you have a leaky gut is to find out “why do I have a leaky gut” and address the root cause of the problem. Patching up a leaky gut with expensive supplements without addressing the ‘why’ is going to be a frustrating experience and is unlikely to fix the root cause. In our IBS and SIBO clinics the sequence of these steps may be taken one at a time or may be grouped together depending on you and your individual case.
Investigating the root cause could include stool and breath testing to look for drivers of permeability and inflammation such as candida, gluten sensitivity, SIBO, SIFO or parasites
Step 2 – Remove the unhelpful inflammatory foods and any contributory lifestyle choices.
For example to start to improve your gut health, begin by limiting your intake of processed foods, in particular those that are high in refined carbohydrate and high in sugar.
Limiting the use of NSAIDs but addressing the root cause of gut discomfort can help also.
Step 3 – Increase anti-inflammatory beneficial foods and positive lifestyle choices
High fibre plants and eating a good diversity of fruits and vegetables support good gut health.
Probiotic supplements can be beneficial in correcting imbalances in the gut microbiome or any gut dysbiosis (imbalanced bacteria). Initially these are generally not recommended if you are also dealing with SIBO or SIFO.
Fermented foods such as organic yoghurt. Kimchi, kefir, sauerkraut and kombucha can also help to improve gut health but these are generally not initially recommended if you are also dealing with SIBO or SIFO.
Bring in stress management techniques and address work life balance
Step 3 – Repair the gut.
Testing for leaky gut
Advanced Intestinal Barrier Assessment (AIBA) https://smartnutrition.co.uk/digestion/digestive-testing/advanced-intestinal-barrier-assessment-aiba/
About this test
The Advanced Intestinal Barrier Assessment is a useful profile to consider if you suspect you have intestinal permeability or ‘leaky gut’ and want to know what imbalances may be driving that process. This test was designed out of years of practice of integrative practitioners who recognise we can improve health by improving the gut through diet and other interventions.
This is the only profile on the market that assesses this combination of markers as possible drivers of intestinal permeability:
- Zonulin
- Histamine
- Diamine Oxidase (DAO)
- Lipopolysaccharides (LPS) IgA, IgG, IgM
Why do the AIBA Profile?
Key symptoms which suggest this profile could provide valuable clinical information include:
- Symptoms suggestive of food intolerance
- Symptoms suggestive of chemical hypersensitivity
- Symptoms suggestive of elevated histamine/histamine intolerance
- Symptoms of fatigue
- Eczema/frequent skin rashes/urticaria
- Previous diagnosis/suspicions of auto-immunity
- Altered mood/depression
What is being measured?
Zonulin
Zonulin is a protein that plays an important role in the opening of small intestine tight junctions. This molecule is used as a non-invasive marker of gut wall integrity. The presence of Zonulin suggests an increase between the intestinal cells gap junction, causing Zonulin to be secreted. It is an early marker of disease, elevating 2-5 years in advance of autoimmune, diabetes and allergic diseases.
Stool Zonulin levels need to be shown in context of other permeability markers and current presenting symptoms. Whereas blood Zonulin levels are well researched to correlate with intestinal permeability, as demonstrated in papers by the Zonulin pioneer Dr Fasano.
Diamine Oxidase (DAO)
Diamine oxidase (DAO) is the body’s primary enzyme for breaking down ingested histamine and a natural defence against histamine excess. If you ingest too much dietary histamine or produce more than your DAO level can handle, reactions can occur. DAO is produced in the microvilli of a healthy small intestine, certain drugs, foods, and bacteria may suppress its production.
Low levels of DAO are associated with the following symptoms and conditions:
- Migraine, headache
- Chronic fatigue
- Hives, skin rash, eczema, psoriasis
- Nasal congestion, asthma
- Gastrointestinal disorders, inflammation, irritable bowel syndrome
- Dysmenorrhea, PMS, oestrogen dominance
- Arrhythmia, hypertension, hypotension
- Fibromyalgia, muscular pain
- Rheumatoid arthritis
- Neurological conditions such as multiple sclerosis and attention deficit and hyperactivity disorder (in childhood and adolescence)
- Depression and anxiety
Histamine
Histamine is involved in many types of allergic and inflammatory processes, including immediate and delayed hypersensitivity reactions. Histamine imbalances in the body may cause a variety of adverse effects ranging from life-threatening allergic reactions to localised itching, runny nose or hives.
An excess of histamine may be a result of ingested histamine (from certain foods), released histamine from storage sites in the body due to food or environmental triggers, or a diamine oxidase (DAO) deficiency which is needed for the breakdown of histamine. Testing histamine along with diamine oxidase (DAO) levels provides important information that standard food sensitivity tests may not reveal. When suspecting food sensitivities, it can be important to also consider histamine intolerance.
DAO: Histamine Ratio
The DAO:Histamine ratio helps identify the imbalance between DAO and histamine levels. Even if DAO is reported as normal, if histamine is high, symptoms can still occur.
A low ratio can provide evidence of insufficient levels of DAO enzyme activity relative to the current level of histamine in the body.
Lipopolysaccharides (LPS)
In humans, the presence of LPS triggers can trigger an immune response producing inflammation.
LPS are found on the outer surfaces of some gut bacteria and when found in the blood, it means they are passing not only between intestinal cells, but also directly through the cells, potentially causing inflammation.
Elevated levels may be associated with bacterial infection, food sensitivities, chronic inflammation, autoimmune conditions, digestive disorders, and neurological conditions.
FAQ
Q1: What is leaky gut?
Leaky gut (intestinal permeability) is a condition where the single-thickness cells of the gastrointestinal tract inner lining move slightly apart and remain apart. This allows bacteria, toxins, and undigested food particles to cross into the bloodstream, triggering immune responses. Research by Dr Alessio Fasano has shown leaky gut is linked to autoimmune diseases, inflammatory conditions, and many digestive disorders.
Q2: What are the symptoms of leaky gut?
Symptoms include bloating, flatulence, cramps, food allergies and sensitivities, joint aches and pains, sleeping issues, depression, skin issues (rashes, eczema, acne), brain fog, fatigue, and immune dysregulation. Leaky gut rarely stands alone — it is typically part of a wider health picture that includes SIBO, candida, or other gut conditions.
Q3: What causes leaky gut?
Common causes include SIBO (up to 50% of people with SIBO have intestinal permeability), SIFO, regular use of NSAIDs and PPIs, antibiotics, chronic stress, excessive sugar intake, excessive alcohol, nutritional deficiencies (particularly vitamins A and D and zinc), chronic inflammation, poor gut health, and yeast overgrowth.
Q4: How is leaky gut treated?
Treatment follows three steps: first, find and address the root cause (SIBO, candida, gluten sensitivity, parasites etc.) through testing and investigation. Second, remove inflammatory foods and unhelpful lifestyle factors. Third, repair the gut lining with targeted nutritional support including anti-inflammatory foods, appropriate probiotic support (noting that probiotics are not initially recommended if SIBO or SIFO is also present), and gut-repair supplements.
Q5: What is the AIBA test for leaky gut?
The Advanced Intestinal Barrier Assessment (AIBA) is a specialist test that measures zonulin, histamine, diamine oxidase (DAO), and lipopolysaccharides (LPS IgA, IgG, IgM) — the key markers of intestinal permeability. This is the only profile on the market assessing this combination of markers. It is particularly useful when food intolerance, histamine symptoms, eczema, rashes, autoimmune suspicions, or altered mood are present. Testing is arranged as part of a consultation.