The fruit offer is bigger and more varied today than ever. But not everyone can enjoy fruit without restriction. Are you also one of those people who often experience rumbling in the stomach after eating fruit? Then there may be a fructose malabsorption or intestinal fructose intolerance.
Test for fructose intolerance
How many people in Germany suffer from fructose malabsorption is not known exactly. Many seem to be affected without a diagnosis being made.
This is quite simple with the help of a test, the so-called "H2-breath test": This fructose malabsorption test measures whether the typical intestinal gases are produced and exhaled after exposure to fructose via the respiratory air.
Fructose malabsorption: what are the causes?
In fructose malabsorption, the uptake of fructose, ie fructose, which occurs for example in fruit and honey, is disturbed in the small intestine. Normally, a transporter transports the sugar component fructose from the food into the small intestine cells and thus into the bloodstream. In fructose malabsorption this transport system is defective or its performance is limited.
Largely undigested, the fructose therefore reaches the large intestine in larger quantities. The bacteria there reduce fructose to short-chain fatty acids and gases such as hydrogen or carbon dioxide, which can trigger the symptoms.
Delineate hereditary fructose intolerance
Not to be confused is fructose malabsorption with congenital (hereditary) fructose intolerance. This is a rare disturbance of the fructose metabolism, in which the affected person lacks an enzyme that is needed for fructose degradation. It requires a strict renunciation of fructose from birth.
Symptoms of fructose intolerance
Typical signs of fructose intolerance usually include a combination of some of the following symptoms:
- Abdominal pain or cramps
- visibly inflated belly
- (foul-smelling) flatulence
- Diarrhea or constipation
- Difficulty concentrating, tiredness or headache
If the affected persons avoid fructose, the symptoms completely disappear. A complete renouncement of fructose does not have to be even with fructose malabsorption, because a small amount of fructose is usually tolerated.
The fructose compatibility is different from person to person and individually determined. In some people, the symptoms of fructose malabsorption are temporary, while in others, fructose can be a life-long problem.
Fructose intolerance - what to do?
After the diagnosis of a fructose intolerance, a waiting period is usually first recommended in which fructose is completely omitted.
Then, step by step, you can (and should) integrate fructose-containing foods into your diet and test your own limits. Over time, as the intestines continue to recover, these boundaries can be pushed further and further.
A doctor or nutritionist can help create an individualized nutritional plan to help prevent malnutrition. Frequent consequences of fructose intolerance are a lack of zinc or folic acid, so - after consultation with the attending physician - a feed on dietary supplements may be useful.
Diet: Which foods to avoid?
The simple sugar fructose is a natural component of fruits and numerous vegetables. Particularly fructose-rich are, for example:
Fructose is also found in fruit juice, fruit yoghurt, cereal bars, dried fruit, jam, confectionery, lemonade and cola. Also, foods such as bread or sausage are often added fructose.
Therefore, with fructose intolerance, it is important to read the ingredients lists carefully while shopping. However, caution is advised when labeling "fructose-free" or "without fructose": this often only means that no additional fructose has been added. Nevertheless, fructose may be present in these foods.
What to eat at fructose malabsorption?
A fructose incompatibility means only in very few cases a complete abandonment of East and vegetables. On the contrary: a complete renunciation can lead to vitamin deficiency and is therefore not advisable.
Comparatively well tolerated in fructose intolerance, for example:
Compatibility may also depend on the type of preparation, the combination of different foods in a meal and the total amount of fructose consumed on that day. The time of day or the time of eating can also play a role. So fructose is directly after a main meal and in the afternoon usually better tolerated.
Special recipes and tables with information on the fructose content of foods can make it easier for those affected to enjoy low fructose cooking.
Sugar with intestinal fructose intolerance
The sugar substitute sorbitol should also be avoided in fructose malabsorption. Since sorbitol in the intestine uses the same means of transport, it can reduce the intake of fructose in the short term. Sorbitol is found in some fruits and is added to many products - just like fructose - as a sugar substitute.
Glucose (grape sugar) on the other hand encourages fructose uptake, as it stimulates the activity of the transporter. For this reason, sucrose (table sugar), half of which is fructose and glucose, is better absorbed by some. It may also be helpful in fructose intolerance to add glucose occasionally when cooking fruit or vegetables to increase the digestibility of a dish.
For sweetening stevia or rice syrup are also suitable - are not suitable Agave syrup, honey or maple syrup. Milk sugar (lactose) may also be an alternative in fructose intolerance, unless lactose intolerance is also involved.