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Fructose Malabsorption Breath Test


Analysis of breath hydrogen and methane after an oral fructose challenge to determine fructose intolerance / fructose malabsorption.


Love fruit, but it just doesn’t love you? Fructose intolerance often leads to folk avoiding fruit because it upsets their digestion. There is good news! The test will for fructose intolerance can be done at home. It’s as simple as catching your breath.

Fructose Intolerance or Fructose Malabsorption?

The terms are used interchangeably. Mainly because whether you’re a malabsorber or not, you’ll be intolerant of fructose!

For a few people fructose intolerance is an inherited disorder, affecting relatively few people – about 1 in 20,000 to 1 in 30,000. It is a genetic mutation in the ALDOB gene, which means that the cells lining the intestines cannot absorb fructose normally. This can cause bloating, diarrhoea or constipation, flatulence (gas or wind), and tummy pain.

The inherited disorder is usually diagnosed in childhood, as the infant demonstrates poor growth (failure to thrive). You can read more about the hereditary disorder here.

The more common type of fructose malabsorption is a bit different, but it affects up to 40% of people in varying degrees. Read about that here. There are several possible reasons behind it, and is an interesting area of research.

How is Fructose Normally Absorbed?

Fructose is a simple, single sugar molecule (a monosaccharide), and unlike the dairy sugar, lactose, it does not require an enzyme for absorption.

Unabsorbed fructose is a FODMAP, meaning it will ferment in the large bowel. This can cause problems.

There are two ways fructose gets absorbed.

  1. By means of a specific fructose transporter (called GLUT5), found along the entire small intestine. Absorption of fructose by this method is slow.
  2. Absorption happens only in the presence of glucose and is much faster. So when there is relatively more fructose than glucose it may not be absorbed.

Symptoms from fructose malabsorption occur if fructose is met by bacteria – either due to excessive bacteria in the small intestine (SIBO) or because of rapid transit to the large intestine (where bacteria are normally found in high numbers).

How Does the Fructose Malabsorption Test Work?

Testing by measuring breath gases is a validated assessment method, using a dose that replicates a high dietary intake to provoke symptoms (Ref). A positive result requires a nutritional consultation to explore further and help you manage the symptoms.

Testing for fructose intolerance requires TWO breath tests: lactulose, then fructose. Each test is done on a different day, at least 2 days apart. Our test measures both hydrogen and methane.

Please note: test results are delivered in the context of a professional consultation – either in our clinic, by tele-consult or to the registered health consultant you specify.

How is the Fructose Intolerance Test done?

  • After ordering the test kits, you will be sent the collection equipment and instructions.
  • Each test is collected in the morning, after an overnight fast.
  • In order to perform this test at home you will need to restrict your diet of the 24 hours prior to the test. Diet preparation instructions are here.
    Please watch 
    this video which explains the procedure.
  • Correct technique for collection is critical, otherwise your samples may be invalid. If you are not sure that you can collect the samples correctly, please make an appointment to conduct the test in-clinic (by appointment)
  • You will collect a baseline breath sample, and then take a drink with dissolved test substance mixed with water.
  • Collection of subsequent breath samples is done following the specific instructions for each test sugar.

What will I need to do the Fructose Intolerance Test?

  • A timer (the one on your cellphone is perfect)
  • Water and glass
  • A pen
  • A morning at home for each of the two tests.

Everything else is supplied in the test kits.

Once the first test has been completed, you can eat and drink normally, resuming the test preparation diet for one full day prior to conducting the second test.
Package the tubes in the box they came in, place in the courier bag provided and either phone the courier (the number is on the instructions with the kit) or take it to your post office.
The results will be released to your health-care provider.

CAUTION: Do not conduct this test if you are a Type 1 diabetic. Please contact us to discuss. Phone 09 846 5566

Looking for a different breath test? Go here

Weight 1 kg
Dimensions 10 × 10 × 20 cm

Lactulose & Fructose, Fructose only


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