SIBO – Fructose Breath Test

The fastest Fructose Intolerance Test, complete at home and get your results in 3 days. Fructose intolerance may be contributing to your digestive symptoms, especially if they are exasperated by fruit or fruit products.

SIBO – Fructose Breath Test

The fastest Fructose Intolerance Test, complete at home and get your results in 3 days. Fructose intolerance may be contributing to your digestive symptoms, especially if they are exasperated by fruit or fruit products.

Is the SIBO fructose test the right for me?

Are your IBS symptoms triggered when you eat fruit? Does fruit, fruit drinks or packaged sweetened food cause diarrhoea, bloating and gas? 

 

Fructose Intolerance vs SIBO: What’s the Difference?

Fructose intolerance occurs when the small intestine is unable to absorb fructose efficiently. Fructose is a natural sugar found in fruit, honey, and some vegetables, and is also commonly added to processed foods in the form of high-fructose corn syrup. When absorption is impaired, unabsorbed fructose travels to the large intestine, where it is fermented by gut bacteria. This process produces gas and other by-products, leading to symptoms such as bloating, wind, abdominal pain, cramping, and diarrhoea.

There are two main types of fructose intolerance:

  • Hereditary Fructose Intolerance – a rare genetic condition that affects the liver’s ability to process fructose.

  • Fructose Malabsorption (Dietary Fructose Intolerance) – a more common condition where the small intestine does not absorb fructose properly.

Fructose malabsorption can sometimes be secondary to an underlying condition, such as Small Intestinal Bacterial Overgrowth (SIBO). In SIBO, excess bacteria in the small intestine ferment sugars like fructose prematurely, which can trigger symptoms similar to fructose intolerance.

What Is the  SIBO Fructose Breath Test?

The Fructose Breath Test is used to assess how well your body absorbs fructose and whether unabsorbed fructose is being fermented by gut bacteria. While it is primarily used to diagnose fructose malabsorption the extended breath sampling (usually 10 samples over several hours) makes it a useful tool for detecting SIBO, especially when symptoms overlap.

  • This convenient at home fructose intolerance / SIBO test kit helps you investigate whether this is contributing to your digestive and health issues.
  • 10 breath samples collected over 3 hours ensure more accurate results.
  • Results include insights from our Certified Functional Medicine team along with a GP’s comment, with over 21 years of Fructose Intolerance and SIBO expertise and thousands of test reports reviewed.
  • Fully Accredited Lab
  • All postage costs are all included with your Fructose Intolerance test kit. Delivery to you and back to the lab.
  • Support the environment and save money. Our UK lab maintains low costs, and your samples never travel internationally to Europe or the USA, minimising carbon emissions.

At Smart Nutrition we pride ourselves in offering the best cost possible for the Fructose Intolerance Test UK

add to cart - £142.00

The most common symptoms of fructose intolerance are listed below and these are typically aggravated by eating fruit or fruit containing products:

  • Gas
  • Bloating
  • Diarrhoea
  • Stomach or abdominal pains

These are very similar symptoms to  SIBO.

Fructose intolerance can be genetic (meaning you are born with it), but it can also be linked to other digestive issues such as SIBO. If you have symptoms of fructose intolerance and complete a breath test that includes 10 samples, the results can also be used to assess for Small Intestinal Bacterial Overgrowth, as the test measures how sugars are fermented in the gut over time.

Our at home Fructose Intolerance / SIBO fructose breath test measures levels of Hydrogen and Methane in the breath for diagnosis of dietary fructose malabsorption.

After drinking a fructose drink air samples are collected to measure levels of hydrogen and methane in the breath.

 

 

 

You will need to collect 10 breath samples collected over 3 hours.

 

 

Your kit will include comprehensive instructions.

This test must not be performed on the same day as any of our other breath tests (e.g., lactulose (SIBO) or lactose intolerance).

Before collecting samples for your fructose intolerance breath test you will need to follow a preparation diet and then you will need to fast over night but you also need to make sure you also follow the guidance below too (which will be included in your instructions)

2 weeks prior to doing your at home, Fructose Intolerance Test:

  • You need a break of 2 weeks after antibiotics and herbal antimicrobials before doing the Smart Fructose Intolerance Test
  • Stop taking prebiotics and probiotics, a minimum 48 hours before the test

One day prior to doing your at home, Fructose Intolerance Test:

  • Stop taking laxatives – If these are prescribed by your doctor please get their consent before you stop. Please also stop taking any digestive aids such as digestive enzymes or hydrochloric acid.
  • You should fast for at least 14 hours before you start collecting your breath samples, this means you should not eat any food and only have water to drink. You should continue this fast during the test period and therefore most people prefer to commence the test early in the morning to limit the length of their fast.
  • Do not sleep or exercise vigorously for at least 1 hour before, or at any time during, the test.
  • Do not smoke for at least 45 minutes prior to the start of the test or during the test.

You also need to follow a preparation diet for 24 hours before the test. If you are constipated, please follow the prep diet for 48 days before the test.

The evening /night before doing your at home, Fructose Intolerance Test you will need to fast overnight – water  is allowed.

Prep diet

Choose from:

  • Baked or broiled chicken, fish or turkey (spiced ONLY with salt and pepper)
  • Plain steamed white rice (basmati or jasmine)
  • Eggs
  • Clear chicken or beef broth
  • Olive oil or coconut oil – 1 tablespoon only, for cooking
  • Black tea or coffee

Avoid all other types of food during the prep diet to ensure accurate results. Failure to stick to the prep diet will make your results invalid.

Example Meal Plan

BreakfastSnackLunchSnackDinner
Scrambled eggsChicken brothChicken and white rice seasoned with salt and pepperChicken brothFish and white rice seasoned with salt and pepper
Drinks
Water is allowed throughout the day as needed.

 

The Fructose SIBO Test is suitable for:

Adults: suitable for all ages.

If your weight is less than 50lbs you will need to speak to us and consult your medical professional to discuss a suitable dosage of the solution prior to completing this test.

Children: Children need to be competent in blowing into a balloon and we need to know the weight of your child so that we can advise about the correct amount of fructose for the test.

Please speak to us and consult your medical professional to discuss a suitable dosage of the solution prior to completing this test.

The cost of UK return postage is covered by your fee for the Fructose Intolerance test and it will arrive with a fully paid and addressed envelope for you to easily return your samples.

Samples returned from outside of the UK. The vials can be posted by airmail if you’re outside the UK. Any fee for this is not included in the Fructose SIBO test fee.

Samples need to arrive back at the lab within 7 days of completing the samples.

 

 

Your Fructose SIBO test results will be ready in 5 working days.

We will email your Fructose Intolerance test results to you with comments from our functional medicine team along with an interpretation guide.

Should you need any further help with your results you can book in for a phone call and speak to one of our SIBO and breath test experts. We want to be sure you fully understand the test findings and the options available to you to help you to address your results too.

Is the Program to Treat SIBO Included in the Cost of the Test if My Results Are Positive?

Unfortunately, no. The cost of the Smart SIBO test covers the test only.

Why Don’t We Include a Plan to Address Your SIBO Along With Your Results?

Because everyone is different, and SIBO is chronic in two-thirds of people, meaning it often recurs unless you address the underlying reasons. Treating SIBO requires addressing the root cause (or causes), so an off-the-shelf program wouldn’t be suitable for everyone.

There are various treatment options available for SIBO, depending on whether you are hydrogen or methane positive, whether your symptoms and results indicate hydrogen sulfide positivity, and whether SIFO (small intestine fungal overgrowth) is a concern.

A comprehensive program should also address any other digestive imbalances that may be causing or contributing to your SIBO. Therefore, we believe an off-the-shelf plan is not the right option to ensure resolution of your SIBO.

Instead, we collaborate closely with a group of Functional Medicine practitioners and experienced nutritional therapists, along with a private GP.

You will receive details of these practitioners with your results if you want to explore a bespoke, personalized plan. This plan will carefully investigate, track, and support your individual SIBO and digestive health needs.

 

 

 

Preparation for the Test

You will receive full instructions with your SIBO test kit. To prepare for the test, you need to follow a specific diet for one day, or two days if you are constipated, before the test. Additionally, you must fast overnight before performing the test, though water is allowed during the fasting period. The instructions will detail which foods you can eat and include a meal plan.

On the Day of the Test

In the morning, you will take a control breath sample and then drink the solution provided with the test kit. You will collect a breath sample every 20 minutes for the next three hours. After the final sample, you can eat and drink as usual.

Frequently Asked Questions

Should I remove the grey rubber around the needle of the breath collecting kit? No, do not remove it. The grey rubber helps produce a good seal around the vial.

There is a hole in the blue breath collection bag. Should I tape it up? No, the hole is intentional. It ensures the correct breath sample is collected.

Any tips for taking the breath sample? Watch the instructional video for guidance. Standing in front of a mirror can help you see what you are doing.

Should I be able to see my breath in the test tube? You generally won’t see your breath in the test tube, but you might notice some condensation.

Returning Your Samples

Samples must arrive back at the lab within seven days of collection. If you are outside the UK, the vials can be posted by airmail.

Getting Your Results

Results are returned within three working days. Once processed using certified Quintron equipment, your results will be plotted on a graph. A rise in hydrogen, methane, or both at inappropriate points will indicate fermentation and the presence of bacterial overgrowth, confirming SIBO

Please find a sample report here

All sample reports are for representational and educational purposes only. Biomarkers, references ranges, results, and all other data may differ from actual reports. All data included in no way represents an actual patient. Any comparisons of results to actual patients is completely incidental. 

Updated 

May 30, 2025

SIBO – Fructose Breath Test

add to cart - £142.00

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Please do not return samples to the laboratories that may arrive after Wednesday 27th March and up to and including Monday 2nd April.

The laboratories are closed from the 28th March – 2nd April for the Easter Holiday.