A big problem is that the symptoms vary. That's why most people don't immediately think of fructose intolerance when they go to the doctor. Here are some summarised symptoms that can occur, but don't have to (actually only if you eat something "wrong") - this is different for everyone. As long as you cut out the food triggering things, the symptoms should not occur.
- Abdominal pain to a really bloated stomach. (the classic after "wrong" fruit or juice)
- Bloating because the body cannot process the fructose. This is what causes the gases.
- Belching because the gases also escape upwards.
- Diarrhoea (daily to hourly) and/or constipation - both are possible.
- Fatigue - you just can't get anything done because you have no energy.
- Tiredness to the point that one's eyes simply fall shut, one cannot stay awake with the best will in the world. Even if you sleep, it does not bring you any rest.
- Headaches can go as far as migraine with aura (i.e. impaired vision, etc.) - in our experience, this lasts for 1 - 3 days and unfortunately no classic headache tablets usually help.
- Confusion, because the brain is no longer able to think. The simplest things and actions are extremely difficult, you "forget" what or where you wanted to go.
- The psyche also suffers from fructose intolerance. Perhaps everyone has experienced this: you eat the wrong thing and your thoughts soon start to "spin". The website https://fructoseintoleranz.com/fructoseintoleranz-und-die-psyche explains this phenomenon and other things well.
The most common symptoms of fructose intolerance.
Testing fructose intolerance
Fructose intolerance can be tested by a doctor or in a specialised clinic with an H2 breath test. Before the test, however, you must not eat anything for 12 hours and only drink water. On the day of the test, you drink a solution containing fructose and then have to blow into a tube at intervals, where the ppm content in the breath is measured. If you get a test result above 20 ppm, you are fructose intolerant. ATTENTION - it is best to take a companion with you, because you may not feel so well afterwards. On the same day or even the next morning, diarrhoea and vomiting may occur, as the body "fights back" against the fructose.
At DGE (German Society for Fructose Intolerance) there are food tables, information about the H2 breath test to determine fructose intolerance and many other things. https://www.fructose-intoleranz.info
Simultaneous sorbitol intolerance
Most people with fructose intolerance also have a simultaneous sorbitol intolerance. This can be tested with an H2 breath test.
Negative H2 breath test despite symptoms
If the H2 breath test is negative, but you still have problems with your symptoms, you may have a "non-producer status". In this case, the H2 breath test cannot detect an increased hydrogen content, but large amounts of fructose still enter the intestine undigested.
Medicines and cough syrup for fructose intolerance
Please also be careful with medicines! Many contain sorbitol or similar substances. Or classic throat lozenges with honey. Here, everyone must test for themselves what the body can tolerate.
Why glucose is good
It can serve as a so-called "rucksack" when eating. Dextrose helps some people to better digest their "normal" food. However, the success is different for each fructose intolerant person.
Fructose/glucose ratio (calculate)
The fructose/glucose ratio should be as close to 1:1 as possible. The food should have more glucose than fructose, or at least be equivalent. See also the book Complaint-free with the 3-phase programme.
On the website https://www.naehrwertrechner.de/naehrwerttabelle you can get all the values for fructose, sucrose etc.. Simply enter the food and have it calculated. This is also possible for several foods for recipes.