Intestinal permeability, also known as "leaky gut," refers to the condition in which the lining of the small intestine becomes damaged, allowing undigested food particles, toxins, and bacteria to "leak" through the gut and into the bloodstream. This can lead to inflammation and an immune response, as well as a host of other health problems.

There are many causes of increased intestinal permeability, including:

1. Chronic stress: stress can cause inflammation in the gut, leading to damage of the gut lining.

2. Poor diet: a diet high in processed foods, sugar, and artificial ingredients can disrupt the balance of good and bad bacteria in the gut, leading to inflammation and damage.

3. Excessive alcohol consumption can disrupt the gut lining and lead to inflammation.

4. Certain medications: non-steroidal anti-inflammatory drugs (NSAIDs) and antibiotics can damage the gut lining, leading to increased permeability.

5. Inflammatory bowel disease (IBD) such as Crohn's disease and ulcerative colitis.

6. Food allergies and sensitivities.

7. Bacterial imbalances, such as overgrowth of harmful bacteria in the gut (including SIBO)

How to test for leaky gut

1. Lactulose-mannitol test: this test involves drinking solutions of two sugars (lactulose and mannitol) and measuring the amount of each sugar that is excreted in the urine. If there is increased permeability in the gut, more lactulose will be excreted, indicating that it was able to pass through the gut lining and into the bloodstream.

2. Zonulin test: zonulin is a protein that regulates the tight junctions between gut cells, and when present in high levels it can indicate increased gut permeability. A blood or stool test can measure the levels of zonulin. I find this test less reliable in most cases.

3. Fecal calprotectin test: this test measures the levels of a protein called calprotectin in the faeces, which can indicate inflammation in the gut.

4. Antibodies test: this blood test looks for antibodies to food proteins, indicating that they have passed through the gut lining and entered the bloodstream.

Tests should be selected and interpreted in the context of your symptoms and medical history. It is important to have a consultation to determine which test may be most appropriate for your individual case.

Conditions and symptoms associated with increased intestinal permeability include:

• Digestive problems such as bloating, gas, constipation, and diarrhea.

• Food allergies or sensitivities: undigested food particles and toxins can pass through the gut lining and trigger an immune response.

• Fatigue and brain fog: toxins and bacteria can enter the bloodstream and affect the brain and other organs.

• Skin problems such as eczema, acne, and rashes, as toxins and bacteria can also affect the skin.

• Joint pain and arthritis: the immune response caused by a leaky gut can also affect the joints.

• Autoimmune diseases: chronic inflammation caused by a leaky gut can lead to an overactive immune system, which can attack the body's own cells and tissues

• Mood disorders: gut health is closely related to mental health and a leaky gut can lead to low mood, anxiety and depression.

These symptoms can also be caused by other conditions and it is important to book a consult to determine the underlying cause.