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Intestinal Permeability Test


Intestinal permeability (leaky gut) can be the link between gut imbalances and systemic illness. This test can provide direction to heal the gut and address your health concerns.


Commonly referred to as “leaky gut”, increased intestinal permeability is associated with many health conditions including skin problems, autoimmune disorders, food sensitivities, autism and learning disorders, inflammatory bowel disease and many more. This ‘leaky gut’ causes disease because the disrupted barrier of the intestines lets toxic molecules to enter the bloodstream and poison the body. This will be magnified if a person also has bacterial overgrowth in their intestines, or a large population of some types of bacteria that produce toxins!

The gastrointestinal tract has two main functions; a) to digest and absorb important nutrients for the body’s growth and function, and b) to act as a barrier to keep harmful substances, immune compounds and
microorganisms (bacteria, parasites etc.) from entering the blood. When the integrity of this complex system is disturbed and increased intestinal permeability exists, ill-health can easily develop. Many conditions such as autoimmune disorders, autism, food sensitivities, inflammatory bowel disease and jaundice are associated with increased intestinal permeability, which is also known as ‘leaky gut’.

How is Intestinal Permeability Measured?

Intestinal permeability can be measured using the lactulose/mannitol recovery test.

What About Malabsorption?

In addition to assessing leaky gut, this test can also help diagnose malabsorption. If a low level of mannitol which normally penetrates the intestinal epithelium is observed, it may indicate malabsorption of small molecules and possible atrophy of the intestinal villi. If you suspect you have lactose intolerance or fructose malabsorption, then those tests are more specific.

How Does the Test Work?

The test works on the principle that small molecules are readily absorbed by the intestinal cells, whilst larger molecules are not. The test involves taking a drink that contains two water-soluble sugars that do not get metabolised by humans. If absorbed into the bloodstream (via the gut lining) they are excreted into the urine. The mannitol is expected to be absorbed to some extent, but the lactulose should normally be excluded by a healthy gut lining.

Watch this video for test collection instructions:

How is the Test Interpreted?

In a healthy gut the ratio of lactulose to mannitol in urine is low (i.e lactulose is not absorbed), mannitol is absorbed. When the structure of the intestines is jeopardised (i.e., ‘leaky gut’ is present), the large sugar molecule can get through and is able to be measured 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.

When Should I Consider Taking an Intestinal Permeability Test?

Common conditions in which leaky gut (intestinal hyperpermeability) may be involved include:

Is there Another Way to Measure Intestinal Permeability?

The discovery of a protein called zonulin has added another way of measuring intestinal permeability, as zonulin is a protein that helps regulate how the cells hold together in the gut lining. Zonulin is increased in situations where there are bacteria in the intestines and due to ingestion of gluten (the protein found in wheat, rye and barley). We can also measure zonulin in a stool test. The result is confounded by gluten intake.

What is the Test Method?

The laboratory uses Automated Chemistry- Enzymatic

Is there any Special Preparation for the Intestinal Permeability Test?

After avoiding a few foods the night before, you have an overnight fast (about 10 hours). In the morning (after urinating), you take a drink with the test sugars and collect your urine for the next six hours.
A sample of this is sent to the lab..

How Long does it Take to Get the Results?

Test results typically take about 4 weeks. We suggest you make your appointment booking to coincide with the expected return of your results. Our Registered Naturopath is trained in interpretation and can guide you on the next steps to heal your gut and optimise your digestive health.

Are there other things that can help me?

YES.. We recommend a comprehensive appointment with one of our Registered Naturopaths to take a comprehensive health, digestive and medical history.

If you aren’t sure if this is the right test for you, please call us on 09 8465566





Weight 0.2 kg
Dimensions 15 × 5 × 26 cm


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