A healthy digestive system often goes unnoticed, quietly supporting every aspect of your well-being. It’s only when something goes wrong, when symptoms like bloating, indigestion, or abdominal discomfort appear, that the digestive system demands attention.
But what if your gut health is undermining your overall wellness without obvious digestive symptoms? Could an issue like leaky gut syndrome be silently at play?
As Aristotle famously said, “All disease begins in the gut”. While this may not apply to every health issue, mounting evidence links an increasing number of conditions to the incredible ecosystem of microbial communities that live in our gut.
This article explores what leaky gut syndrome is, its potential impacts, and how you can take steps to address it.
What is leaky gut syndrome?
Leaky gut syndrome, also called intestinal hyperpermeability, refers to a condition where the lining of the small intestine becomes permeable or damaged, allowing undigested food particles, toxins and bacteria to “leak” through the intestinal wall into the bloodstream, triggering immune responses and inflammation.
The small intestine is designed to act as a selective barrier, with structures called tight junctions between its cells. These junctions allow essential nutrients to pass into the bloodstream while keeping harmful substances out.
However, poor dietary choices, stress, and other factors can weaken these junctions, leading to a compromised intestinal barrier.
What are the symptoms of a leaky gut?
Intestinal permeability does not always present with a digestive symptom. Some symptoms that could indicate a leaky gut are:
- Brain fog
- Headaches
- Joint pain
- Autoimmune disease
- Muscle pain
- Systemic inflammation
- Cardiovascular disease
- Metabolic syndrome
- Food sensitivity, etc.
Digestive symptoms, like bloating, diarrhoea, or excessive gas, can also be early warning signs. Left untreated, these can contribute to intestinal inflammation and permeability.
What leads to a leaky gut?
A variety of factors can damage the gut lining and increase intestinal permeability:
- Diet: Low-fibre, ultra-processed, or high-sugar diets
- Lifestyle: Chronic stress, poor sleep, lack of exercise
- Substances: Alcohol, smoking, substance abuse, and certain medications (e.g. NSAIDS, Antibiotics, Corticosteroids, Proton Pump Inhibitors, chemotherapy drugs, OCP, SSRIs)
- Health conditions: Coeliac disease, Crohn’s disease, IBS, or SIBO, food allergies or sensitivity, mental health conditions
- Gut microbiome imbalance: Low diversity or harmful bacterial overgrowth
The impact of modern living often combines several of these risk factors, making leaky gut increasingly common.
Foods to include to avoid a leaky gut
The human diet has changed dramatically over the last hundred years, from food that’s consumed soon after harvesting to eating what we want, when we want, in unlimited amounts.
Highly processed foods, genetically modified and nutritionally deficient, may satisfy a ‘hangry moment’ or be convenient in a busy life schedule, but the effects of highly processed foods on the digestive tract can be damaging, inflammatory and result in an overactive immune system.
Maintaining a wholefood and balanced diet is essential for minimising damage to the intestinal tract and encouraging microbiome richness and diversity of good bacteria. Eating an anti-inflammatory diet and being aware of the negative effects of inflammatory foods can be reviewed in our handy anti-inflammatory food guide. Key foods to include are:
- Prebiotics: Foods rich in fibre, polyphenols, or resistant starch (e.g., vegetables, legumes, cooked-and-cooled rice or potatoes). A diverse diet rich in plant-based foods is generally the best way to ensure you’re getting a good mix of prebiotics
- Probiotics: Fermented foods like yogurt, kimchi, or sauerkraut
- Anti-inflammatory choices: Fatty fish, turmeric, ginger, and polyphenol-rich colourful fruits and vegetables
Avoid highly processed, sugary, or inflammatory foods to protect the intestinal barrier and support a balanced microbiome.
Does a leaky gut cause autoimmune disease? The autoimmune connection
Leaky gut has been linked to autoimmune conditions like type 1 diabetes, multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, and inflammatory bowel disease. When the gut lining is compromised, the immune system is exposed to foreign particles that may trigger an autoimmune response, where the body starts attacking itself.
Studies show that overexpression of zonulin, a protein regulating gut permeability, is associated with autoimmunity. This makes managing intestinal health a critical step in reducing autoimmune risk.
Whilst causes of autoimmunity are inconclusive, contributing factors are genetic predisposition, environmental factors and gut microbiome imbalance (dysbiosis).
Is a leaky gut genetic? Genetic factors to consider
According to Dr. Alessio Fasano, director of the Center for Celiac Research and Treatment with Harvard-affiliated Massachusetts General Hospital, the biggest reasons a gut can become leaky are genes and diet. He says:
“Some people may have a weaker barrier because they were born with it, or they follow an unbalanced diet low in fibre and high in sugar and saturated fats, which may be the trigger that weakens the gut lining.”
Age also plays a role, because as you age, cells get damaged more easily and heal slowly, if at all, so the gut becomes more vulnerable.
Certain genetic conditions, such as Ehlers-Danlos syndrome, coeliac disease, type 1 diabetes, Crohn’s disease, may also affect gut barrier integrity.
Can the bacteria in my gut cause a leaky gut?
The gut microbiota, a community of both beneficial and harmful microorganisms, plays a crucial role in overall health. Often likened to a “garden” within the gut – primarily in the large intestine – it’s constantly shaped by the foods and beverages we consume.
A healthy, rich, and diverse gut microbiota is essential for maintaining the integrity of the intestinal barrier. It supports the tight junctions between intestinal epithelial cells, preventing unwanted substances from leaking into the bloodstream.
However, an imbalance in these microorganisms can disrupt this delicate system. Factors such as low microbial diversity, insufficient richness, or an overgrowth of harmful bacteria can lead to inflammation and damage. Certain gram-negative bacteria (Pseudomonas, Klebsiella, Proteus, Salmonella, Providencia, Escherichia, Morganella, Aeromonas, and Citrobacter) produce metabolites with inflammatory effects, further compromising the gut lining. This imbalance significantly increases the risk of developing a leaky gut.
How do I test to find out if I have a leaky gut?
Intestinal permeability (leaky gut) testing can be approached in a couple of ways:
Urine testing
A 6-hour urine collection test is conducted after ingesting two substrates (sugars) – lactulose and mannitol.
The test works on the principle that small molecules (i.e. mannitol) are readily absorbed by the intestinal villi, whilst larger molecules such as disaccharides (i.e. lactulose) are not. These water-soluble non-metabolised sugar molecules after penetrating the intestinal tract are excreted into the urine.
Under normal circumstances, the ratio of lactulose to mannitol in urine is low (i.e. lactulose is not absorbed), and mannitol is absorbed.
When the structure of the intestinal lining is jeopardised (‘leaky gut’ is present), the large sugar molecule can get through the mucosa and is recovered in the urine. In this situation, the level of lactulose is increased in the urine and therefore the ratio of lactulose to mannitol is high.
Blood testing
Markers in the blood can identify inflammation or the likelihood that inflammation may be present in the gut. Markers such as calprotectin, zonulin, specific antibodies, or endotoxins may be assessed and considered to be associated with an increased risk of a compromised gut lining.
How to heal leaky gut naturally
The foundation of all medicine is food, so ensuring a well-balanced, wholefood diet with a variety of protein, plenty of plant foods, nuts, seeds, and good fats should be the first step.
Minimising damage to the gastrointestinal tract by avoiding or reducing alcohol to a minimum, not smoking, managing stress hormones (breath work, meditation, mindfulness, yoga, exercise, etc.) and supporting vagal tone are some lifestyle behaviours to include.
Lastly, supplementation to include in the healing of a leaky gut may be glutamine, aloe vera, slippery elm, zinc carnosine, Vitamin A, anti-inflammatory herbs like turmeric, as well as addressing any evidence of nutritional deficiencies.
The functional medicine approach to treating leaky gut
At Melbourne Functional Medicine, we believe in addressing the root causes of leaky gut by understanding your unique health story.
By diving deeply into your health history and timelines, we identify the unique factors contributing to intestinal permeability. This comprehensive review enables us to pinpoint underlying causes that may be hindering your recovery, providing a clear path forward.
So if you suspect you have a leaky gut, don’t guess – get tested. Our gut health experts can help you pinpoint if you have intestinal permeability or another digestive disorder, and provide support to get your gut health back on track.
