Letzte Aktualisierung am 9. September 2024 von Dr. Michael Zechmann-Khreis
To diagnose intestinal fructose intolerance , it is important to first keep a food and symptom diary for about two weeks. A doctor evaluates the diary and then decides which further tests are necessary for the diagnosis. 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. Fructose intolerance cannot be diagnosed by taking a blood sample either.
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 will be given a certain amount of a test solution (water + sugar to be tested) to drink. You will then be asked to blow into a measuring device at defined intervals to measure the hydrogen content of your breath. 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. 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.
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 only 4 measurements at 0, 90, 120 and 180 minutes are sufficient for a clear diagnosis. However, measurements every 30 minutes are more accurate.
- The fructose breath test can also be used to determine small intestinal colonization. But then you have to blow every 10 minutes. If there is a so-called double peak, i.e. if the ppm values rise after a short time, then fall and rise again later, one can assume a small intestine overgrowth AND a 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.
- The level of the value in the test has no significance whatsoever for the severity of the intolerance
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., “Fruktoseintoleranz, Laktoseintoleranz und Histaminintoleranz: Erste Hilfe nach der Diagnose”, 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. Gut, 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) Atemtests bei gastrointestinalen Erkrankungen, ÖSTERREICHISCHE ÄRZTEZEITUNG, mai 2022, CAZ State of the Art
