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Fructose breath test

I have just had this done today ( finally) and it showed positive.

Does anyone know EXACTLY what this means?

Firstly I am sure it means fructose malabsorption.

Secondly, I was advised that taking a fructose test covers the lactose and glucose tests too so there was no need to test for those two.. So does that mean I malabsorb all 3? AND that I have SIBO?

Just waiting for the report and no doubt a list of antibiotics ( to cause more digestive issues!)

So I hope someone out there can advise more info and maybe some tried and tested remedies other than antibiotics. ( already on FODMAP)


10 Replies

Hi I have just had the SIBO test and my result was negative after being tested for breath test over a 3hour session.Having had to starve first and then I understood that if it had been positive it would have meant over growth of bacteria in the small colon-which can be treated by antibiotic.This was after drinking Glucose. I understood that for other tests one takes diferent sugars. This was through a hospital Gastroenterologist. hope this may help


Hi I have just started using this website, I have had IBS for many years, and have found the FODMAP diet beneficial. I was interested to learn that you have had a Fructose breath test, do you know if this is available in the UK, as my GP did not know of that particular test when I inquired a while ago.


Hi big bun, yes I had it done in London. A year ago I got my GP to refer me to a gastroenterologist. Had a celiac test and then had to research and push for further tests myself.

The fructose test is actually called the Hydrogen Breath test and can be done with lactose, glucose or fructose.

In my case I have been on FODMAPS since feb and knew that sugar was a major issue.

If you're still having slight issues on FODMAPs than I would suggest asking for the test or a referral if the GP is still not clued up on it.

Good luck:-)


Hi Ibsr thank you for the info I will look into it.


Hi Ibsr,

I think it's good that the Gastro's now have some hard data which confirms you have a problem- they don't seem to get very excited about described symptoms.

It would be good if you would share what treatment is recommended.

I'm a bit confused with what this all means myself, however from what I can gather the small intestine is meant to be relatively bacteria free, instead this is where enzymes are meant to be released which then break down nutrients ready to be absorbed via the intestinal wall. The remainder goes through to the colon where bacteria do the work.

If bacteria creep into the small intestine they:

*Create gas which is uncomfortable (I don't think much swallowed air is meant to get far down your gut)

*Create byproducts (one being hydrogen) which are quickly absorbed into the body- some of these byproducts might be toxic to the body. I don't think the hydrogen is bad per se it's just a diagnostic tool, if there are two peaks instead of one there is hydrogen production both in the small and long intestine have

*Create or exacerbate problems with the mucosal layer. This is bad news as the mucosa provides a vital barrier between the outer world and the inner world. A compromised mucosal layer (also known as leaky gut) allows bacteria and debris in through the gut wall possibly leading to a immune response.

Some factors which can lead to bacterial overgrowth in the small intestine are:

* Infections affecting the mucosal layer

* Peristalsis (wave function used to move matter through the gut) not working correctly

*Reduced enzyme production

* Reduced acid production in the stomach

* Problems with the valve between the small and long intestine allowing bacteria to wash back into the small intestine

*Combination of all of the above

I found this animation of the gut recently which helps with understanding things:

As I say this is all my take on it, don't take it as gospel!

Cheers and good luck,



Also I guess you might have a colon y of the wrong type of bacteria (hydrogen) in the long intestine...


Hi J, this is what is so confusing, I have read that in fructose malabsorption the small intestine does not need enzymes to process fructose.

Once it gets into the LI, it can either back flow to the SI due to a faulty ileo cecal valve. Or it can stay in the LI and leak into the walls and the blood supply, hence foggyness etc.

Am still looking at alternative ways to treat this and there is not much out there to help:-(


OK just using deduction we could maybe assume that the mucosal layer has been compromised for some reason and 'bad' bacteria have taken hold so rather than the fructose being absorbed directly into the body, instead it is being metabolised by the bacteria.

If you are looking for alternatives a friend has recommended berberine/ berberis tincture with total recovery - he went on an exclusion diet and used the tincture for 6 months.


Thanks, will look into that:-)



It turns out that I was advised wrong info at my fructose testing. I DO have to go back and be lactose tested now. Don't you just love the lack of knowledge on IBS at the NHS!


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