John Myers
While fruit is generally considered a healthy food that you should incorporate into your diet every day, fructose intolerance can be a problem. What now? A life without fruit? We answer the most frequently asked questions.
Fructose – Fruit sugar is not only found in fruit
Fruit sugar or fructose from Latin fructus (“fruit”) is one of the simple carbohydrates. Contrary to what its name might suggest, it is not only found in fruits. Vegetables can also contain fructose, which is why it is best to consult a nutritional table with information on the fructose content if you have a fructose intolerance.
What does fructose intolerance mean? A definition
Fructose reaches the small intestine after eating fruit, fruit products such as dried fruit, juices and fruit spreads or vegetables. There, a transport protein (Glut5) helps to absorb the fructose through the intestinal wall into the blood. In the context of fructose intolerance, there are various reasons for problems with absorption into the blood. The Glut5 protein, for example, is not available in sufficient quantities, the body is offered too much fructose or the intestinal wall is damaged by inflammation. The fructose, therefore, reaches the large intestine. There, intestinal bacteria form gases from the fructose, which lead to symptoms.
Due to the insufficient intake of fructose, fructose intolerance is technically correctly called fructose malabsorption. Sometimes you also read the terms fructose intolerance or fructose allergy. This form of fructose malabsorption should not be confused with the very rare, genetically determined fructose intolerance. In this case, a genetically determined enzyme defect leads to a congenital intolerance to foods containing fructose and sucrose.
Since fructose naturally occurs in high concentrations in fruit, dried fruit, in particular, can provide significant amounts of fructose. Honey and fruit sweeteners should also be avoided.
How is the intolerance noticeable in fructose intolerance?
Symptoms of insufficient fructose absorption in the small intestine and increased gas formation are flatulence (= flatulence), abdominal pain and diarrhea (= diarrhea). The symptoms regularly appear after eating foods containing fructose. If you want to be sure that fructose intolerance is the problem causing these symptoms, you can see a doctor for a simple hydrogen breath test. During the test, you will drink a liquid containing fructose. If the protein Glut5 is actually missing, hydrogen (H2) is produced in the decomposition processes in the large intestine. This hydrogen is absorbed by the blood and ultimately exhaled. The increased concentration of hydrogen is measured and makes it possible to diagnose fructose intolerance. The test can be performed quickly and does not cause any excessive stress on the patient.
What fruits can you eat?
Everyone – even without fructose intolerance – has only a limited ability to absorb fructose. This is around 35-50 g per hour. If there is fructose malabsorption, the absorption capacity is limited to varying degrees and is usually less than 25 g per hour. However, the tolerable amount can vary greatly and can even be as little as 1 g. Foods such as fruit, fruit products or vegetables contain different amounts of fructose. Depending on how severe your fructose intolerance is, you can tolerate certain fructose-containing foods. A complete renunciation is not always necessary. For example, citrus fruits such as limes, apricots, papaya and melon contain less fructose than cherries, persimmons, grapes, apples or pears.
Eating healthy is therefore also possible with fructose intolerance. You can switch to fruits with a very low fructose content.
In the case of pronounced symptoms of fructose intolerance, however, you should use fructose-free foods such as avocado, lamb’s lettuce, cucumber, fennel, parsley, spinach, or zucchini.
What do you have to pay attention to when eating?
The fact that certain food compositions can influence fructose tolerance is important for your nutrition plan. If there is a lot of sorbitol in the food in addition to fructose, this reduces tolerability. Sorbitol is used as a sugar substitute in many industrially produced foods and is one of the sugar alcohols.
On the other hand, if glucose occurs in the same amount or more than fructose in the food, tolerability increases. Fructose is also better tolerated when consumed with protein or fat. Protein and fat slow down the passage of fructose through the stomach. They arrive more slowly in the small intestine and can be better processed and absorbed. You should take this into account in your nutrition plan adapted to fructose intolerance with delicious recipes and tasty combinations. Eat a creamy quark with apricots or whole milk yoghurt with banana instead of pure fruit such as pineapple, apples, or grapes.
Processed foods can also contain fructose, so pay attention to their ingredient lists. Look for the fructose content of the products. Sometimes the designation fructose or corn starch syrup can also be found on the packaging.
You can also read what sorbitol intolerance is and which foods you should avoid.
