Letzte Aktualisierung am 7. December 2023 von Dr. Michael Zechmann-Khreis
Intestinal fructose intolerance is diagnosed by first keeping a food and symptom diary for about two weeks without following a diet. A doctor evaluates the diary and then decides which further examinations are necessary. In the case of intestinal fructose intolerance, this is the H2 breath test. This involves drinking a fructose solution and then blowing into a breath meter at certain intervals.
Other methods such as TCM, bioresonance, spit tests, hair analyses or similar are demonstrably not suitable for diagnosing fructose intolerance!
How does the hydrogen (H2) breath test work?
Normally, sugars such as fructose, glucose or lactose are already absorbed by the body in the small intestine and do not even come into contact with the bacteria in the large intestine. These bacteria digest these sugars and produce gases, among other things. This is a completely normal process. This is exactly what this test makes use of. This is because the bacteria also produce hydrogen (chemically: H2). The hydrogen molecules are so small that they pass directly into the blood (diffuse) and are then released again via the lungs. The hydrogen content of the breath can therefore be measured and is a meaningful indication of food intolerance.
Preparation for the test
Your doctor should give you detailed advice before the test so that a meaningful test can be carried out. There are recommendations from specialist organizations on how best to prepare for the H2 test:
- Make sure you don’t eat anything 8 hours beforehand and only drink tap water. Avoid “heavy” and flatulent foods such as cabbage or leeks 24 hours before your test. So avoid FODMAP-rich foods, fiber and lactulose).
- Smokers exhale carbon monoxide, which can activate the hydrogen sensor of the test device and thus produce false results. Therefore, do not smoke 12 hours before the test, but above all 2 hours before and during the test.
- If you have taken antibiotics in the last 4 weeks or have undergone a colonoscopy, a meaningful test result is not possible.
- Do not exercise for 2 hours before the test and do not do any physical activity during the test.
Procedure of the H2 breath test
You is given a certain amount of a test solution (water + the test solution to be sugar). Then you will be asked, at defined intervals into a measuring device that measures the hydrogen content of his breath. measures. This is similar to an alcohol measuring device during police checks.
The values of this measurement are given in ppm, i.e. parts per million (parts per million or also mg/l). The first value measured before drinking the measuring solution is the initial value (basal value). The following values, as well as the symptoms that occur, are listed in a table. If one of the values (or two consecutive values) rises above 20 ppm above the basal value, the test is positive. Exception: The test for small intestinal colonization with lactulose (see below). The test is usually over after 2-3 hours, but it may be necessary to extend the test to up to 4 hours. You should therefore allow yourself enough time. If your test result is positive, you will probably experience symptoms in your gastrointestinal tract
Table of the most common breath tests
Search for | Test substance | Quantity | Pust interval | Duration of the test |
---|---|---|---|---|
Lactose intolerance | Lactose | 25-50g | 15 or 30 min | 2 hours* |
Fructose intolerance | Fructose | 25g | 15 or 30 min | 2 hours* |
DDFB | Glucose | 50g | 10-20 min | 3 hours |
DDFB | Lactulose | 10g | 10-20 min | 3 hours |
Sorbitol tolerance | Sorbitol | 5-12g | approx. 20 min | 3 hours |
* If the values have risen a maximum of 10-20 ppm above the basal value after 2 hours, the test should be extended to 4 hours. |
Brief information on the fructose breath test
- A maximum of 25g fructose is tested. More would also produce positive test results in healthy people!
- Symptoms usually occur after 90-180 minutes
- From 90 minutes, an increase in values is to be expected, which usually peaks at 150 minutes
- If the test is positive, diarrhea often occurs after approx. 4 hours
- Even if measurements are not taken every 15 minutes, the test is still permissible. It could be shown that even only 4 measurements at 0, 90, 120 and 180 minutes are sufficient for a clear diagnosis. More exact are measurements every 30 minutes.
- The fructose breath test can also be used to diagnose small intestinal colonization. determine. But then you have to blow every 10 minutes. Is there a so-called double peak, i.e. the ppm values rise after a short time, then fall and rise again later, one can speak of a small intestinal colonization AND fructose intolerance.
- For the H2 breath test for fructose, it is therefore advisable to blow every 10-15 minutes for the first 60 minutes, then every 30 minutes thereafter.
Explanations to the following picture:
The gray line
shows a test person who is not fructose intolerant. Please note
is that the measurement with 4 measuring points (yellow line) compared to the
frequent measurement (orange line), the intestinal fructose intolerance
diagnosed, but no statement on small intestinal colonization
(DDFB) can meet. The blue line shows a test subject with
Fructose intolerance, but without DDFB.
H2 breath test for small intestine colonization
As mentioned above, you can also use the fructose breath test to to diagnose small intestinal dysbiosis (DDFB). So if you a fructose breath test, you can kill two birds with one stone. Flap slain. However, there are two other test substances that are suitable for this: Lactulose and glucose.
With lactulose: If the value after 90 minutes is already increased by more than 20 ppm or higher than the values after 120 or 180 minutes, a small intestinal colonization can be assumed.
With glucose: The general rule here is an increase of more than 20 ppm to the initial value is considered a positive finding. Glucose is very quickly and often does not even reach the rear sections of the small intestine, which is why the lactulose test for the diagnosis of DDFB should be preferred.
Problems with the breath test
Around 10 % of the population are non-H2 producers. They have bacteria that immediately metabolize the hydrogen produced. As a result, it does not get into the breath and therefore cannot be measured. However, as the diagnosis is also based on the symptoms, these patients can also be diagnosed. If severe symptoms occur during the course of the day, the test is also positive despite the hydrogen levels in the breath not increasing. This is why it is so important to document the symptoms on that day and, if necessary, report them to the doctor immediately. Actually, in addition to hydrogen, methane should also be measured in the breath, as this allows non-responders to be identified. However, as these test devices are more expensive, these tests are very rarely carried out in practice.
If possible, your doctor should also carry out a blood test. determine other blood values (in the case of fructose intolerance, these are mainly folic acid, B12, serum amylase, lipase, zinc and iron).
Do H2 home tests work?
Unfortunately not. Hydrogen molecules are so small that they are permanently not be “held” in a plastic or glass container can. The maximum storage time for standard containers is approx. 6 hours, The hydrogen would therefore escape during shipping. Temperature also plays a major role, with even room temperature leading to high for storage. Therefore, the H2 breath test should always be performed directly at the doctor’s, not at home.
Sources
(1) Born Peter, World J Gastroenterol 2007 November 21;13(43): 5687-5691 “Carbohydrate malabsorption in patients with non-specific abdominal complaints”
2) Zechmann,M.; Masterman G., “Fructose intolerance, lactose intolerance and histamine intolerance: first aid after diagnosis”, Berenkamp Verlag, 1st ed. 2012
3) Satish S.C. Rao, Ashok Attaluri, Leslie Anderson, Phyllis Stumbo; “Ability of the Normal Human Small Intestine to Absorb Fructose: Evaluation by Breath Testing”; Clinical Gastroenterology and Hepatology 2007;5:959-963
4) Mastropaolo, G., & Rees, W. D. (1987). Evaluation of the hydrogen breath test in man: definition and elimination of the early hydrogen peak. Good, 28(6), 721-5.
5) Simrén, M., & Stotzer, P.-O. (2006). Use and abuse of hydrogen breath tests. Gut, 55(3), 297-303. doi:10.1136/gut.2005.075127
6) Yang, J.-F., Fox, M., Chu, H., Zheng, X., Long, Y.-Q., Pohl, D., … Dai, N. (2015). Four-sample lactose hydrogen breath test for diagnosis of lactose malabsorption in irritable bowel syndrome patients with diarrhea. World Journal of Gastroenterology, 21(24), 7563. doi:10.3748/wjg.v21.i24.7563
7) Methodology and Indications of H2-Breath Testing in Gastrointestinal Diseases: the Rome Consensus Conference. Alimentary Pharmacology & Therapeutics, 29: 1-49. 2009. doi:10.1111/j.1365-2036.2009.03951.x
8) Breath tests for gastrointestinal diseases, ÖSTERREICHISCHE ÄRZTEZEITUNG, may 2022, CAZ State of the Art