What is fructose intolerance and what are the symptoms?

Any person suffering from fructose intolerance You will begin to realize that fructose is found in many foods. With the right diet, however, the complaints and symptoms can be avoided and complete improvement can even be achieved.

Surprisingly, many people tolerate only small amounts of fructose, and also fructans and FODMAPs. Experts estimate that up to 30 percent of adults in Germany are affected by this type of food intolerance.

For comparison: The much better known lactose intolerance occurs in about 15 percent of Central Europeans, this also because information on fructose intolerance is less reliable.

What about fructose intolerance?

In the intestine there are small carrier proteins, through which the nutrients from the interior of the intestine finally reach the blood. In addition to glucose, fructose is also introduced into the body.

The amount of fructose that can be transported is naturally limited. «That means each person can only tolerate a certain amount of fructose.“, explains Dr. Andreas Leodolter, gastroenterologist and chief physician of the Department of Internal Medicine of the Herne Protestant Hospital.

If the transporter is not working properly, the patient can handle less fructose than a healthy person. Therefore, it is called fructose malabsorptionby causing a limited intake of fructose.

The term “fructose intolerance” either “food intolerance to fructose (FAI)» is rather colloquial and means that a person does not tolerate sugar well and responds with symptoms. Food allergy is when the immune system sees food as “dangerous” and causes an allergic reaction. This is not the case for fructose.

The causes that are responsible for fructose intolerance are not yet known. Presumably, the function of the relevant intestinal transporter decreases in the course of life. Also, fructose has been found in more foods in recent years, for example, in soft drinks, processed and modified products. As a result, people today consume more fructose from food than ever before.

What symptoms does fructose intolerance cause?

The most common symptoms are flatulence and diarrhea. This is triggered by fructose. If it reaches the large intestine, it is broken down by bacteria. This produces gas and some foul-smelling fatty acids, and digestion gets out of sync. In addition, it can also cause abdominal pain, bloating, regurgitation, and nausea. In each human being the symptoms are expressed differently.

How is fructose intolerance determined?

Patients often seek the opinion of different doctors and struggle for years with the symptoms until the diagnosis is finally established. The problem in finding an accurate and rapid diagnosis is that symptoms are very nonspecific.

That is, the most diverse causes can be behind this: there may be lactose intolerance, an irritable bowel, an inflammatory bowel disease, just to mention a few examples. Sometimes the diet is simply to blame for all the symptoms. Onions, cabbage, legumes and an excess of whole grain products can be inflaming your intestine.

CYou should try to specify and observe if the symptoms appear after eating a certain food. If the gastrointestinal specialist suspects that fructose is the trigger, a breath test is performed.

For this, the person drinks – on an empty stomach – a fructose solution and then blows at certain intervals into a device. The hydrogen content in the breath is then measured. If this exceeds a specific value and the person has symptoms, then this speaks in favor of fructose intolerance.

How is it treated?

If the diagnosis is confirmed, the gastroenterologist refers the person concerned to a nutrition expert. So you shouldn’t go your own way to eliminate certain foods and test. Some people try to eliminate fructose completely from the diet, however this is not necessary and otherwise important nutrients may be permanently missing.

A nutritionist will review eating habits together with the patient and tell him how to eat first and for a long time. The therapy begins with a two to four week phase in which it is done largely without fructose.

In a food diary, the patient documents what they have eaten and how they feel afterwards. Discomfort should improve significantly during this time. Then the testing phase begins. Slowly, fructose-containing foods are reintroduced, initially those that contain little. Now it is important to recognize which foods are best tolerated and which ones cause problems.

How to eat well with fructose intolerance

Foods that contain a lot of fructose include apples, pears, mangoes, grapes, dried fruits, honey, pear syrup, apple cider vinegar, fruit and vegetable juices, dates, dried figs, dried apricots, persimmons, cherries, cherries, blueberries, strawberry, raspberry, pomegranate, among others.

The sugar that is commonly used is also made up of fructose. Likewise, fructose is abundant in all sweets. Be careful with “light” products, canned vegetables and diet drinks, check the list of ingredients very well. They are often mixed with these fruity sweetener products.

Many types of fruit are considered well tolerated because they contain little fructose or glucose is present in a favorable proportion. These include bananas, apricots, and dried fruit. Glucose facilitates the uptake of fructose in the intestine.

Do not eat fruits purely, but with a meal (like dessert, for example) or together with dairy products, good fats and proteins. Fats and proteins cause fructose to be absorbed more slowly. This makes the job easier for the diseased intestinal transporter.

Sugar substitutes such as sorbitol, xylitol, and mannitol make it difficult for fructose to be absorbed from the gut, so they should be avoided if possible. These substitutes are found, for example, in chewing gums, sugar-free candies and diabetic products.

If the patient has been able to determine, with the help of a nutritional expert, which foods and what amount of fructose does not cause problems, he can live in many cases without discomfort.

Important: There are no general tips and prohibitions. The patient can eat what he personally tolerates. Also, the compatibility threshold should always be tested. Sometimes, the damaged transport system recovers in the intestine and you can even eat an apple or some honey without regrets or symptoms, hence the importance of finding the diagnosis and working on recovery and diet.