What is fructose intolerance?
Fructose intolerance is a digestive disorder in which your body has problems processing fruit sugar (fructose) properly. If you suffer from fructose intolerance, your small intestine cannot fully absorb the fructose. Instead, it passes into your large intestine, where it is fermented by bacteria. This process leads to unpleasant symptoms such as bloating, abdominal pain and diarrhoea.
Causes of fructose intolerance
The exact causes of fructose intolerance have not yet been fully researched. It is suspected that a deficiency in the transport protein GLUT-5, which is responsible for the absorption of fructose in the small intestine, could play a role. A genetic predisposition or damage to the mucous membrane of the small intestine can also lead to fructose intolerance.
Fructose intolerance symptoms
The most common symptoms of fructose intolerance are
- Bloating
- Abdominal pain and cramps
- Diarrhoea
- Nausea
- Bloated stomach
- Constipation
- Flatulence
Symptoms usually occur within 30 minutes to a few hours after eating foods containing fructose.
Fructose intolerance skin symptoms
Although fructose intolerance primarily affects the digestive tract, in rare cases it can also be noticeable on the skin. Some sufferers report skin problems such as eczema, itching or rashes that occur in connection with the consumption of fructose-containing foods.
Fructose intolerance test
The H2 breath test is the standard procedure for diagnosing fructose intolerance. For this test, you must come to the practice on an empty stomach. First, a breath sample is taken to determine your baseline value. You then drink a solution containing a defined amount of fructose, usually 25-50 grams. In the following hours, further breath samples are then taken regularly to measure the hydrogen content.
If your small intestine cannot absorb the fructose properly, it passes into the large intestine. There it is fermented by bacteria, producing hydrogen. This hydrogen passes through the intestinal wall into the blood and is then exhaled through the lungs. An increased hydrogen content in the air you breathe is therefore an indication of fructose malabsorption.
Treatment of fructose intolerance
The most important measure for fructose intolerance is to change your diet. You should largely avoid foods containing fructose or at least severely restrict them. This includes not only fruit and fruit juices, but also many processed foods in which fructose is used as a sweetener.
Tips for a low-fructose diet
- Avoid apples, pears, mangoes, honeydew melons and dried fruit
- Avoid high-fructose drinks such as fruit juices and soft drinks
- Read the ingredients lists carefully and look out for hidden fructose
- Favour vegetables and fruit with a low fructose content such as bananas, citrus fruits, berries, carrots and spinach
- Replace table sugar with dextrose (glucose)
- Keep a food diary to identify triggers
With the right diet and a little patience, fructose intolerance can be easily managed. You can significantly improve your quality of life and enjoy being symptom-free again.
Frequently asked questions
What can you not eat if you are fructose intolerant?
If you are fructose intolerant, you should avoid foods with a high fructose content such as many types of fruit (especially apples, pears and mangoes), dried fruit, fruit juices, honey and some ready-made products. Sugar substitutes such as sorbitol, xylitol or isomalt can also trigger symptoms and should therefore be avoided.
What can you eat with fructose intolerance?
Fruits and vegetables low in fructose such as bananas, blueberries, lemons, carrots and potatoes as well as starchy foods such as bread, pasta and rice, unsweetened dairy products, lean meat and eggs are usually better tolerated. Professional nutritional counselling can help you to put together a balanced diet despite the restrictions.
How can I get rid of my fructose intolerance?
Unfortunately, fructose intolerance cannot be cured, but it can usually be managed well with the right diet. By consistently switching to a low-fructose diet, most sufferers can live symptom-free in the long term.
