Food intolerance: what causes it?

What is a food intolerance?

In the case of a food intolerance, the organism of the affected person is not able to properly digest certain components of a food or to metabolize them. For example, people who suffer from lactose intolerance often experience diarrhea and flatulence after consuming dairy products due to their lack of the lactose-splitting enzyme lactase.

How does a food intolerance develop?

Although most sufferers are born with food intolerances, many people acquire them over the course of their lives. One of the most common causes is an enzyme deficiency or an enzyme defect. If certain enzymes are missing in the intestine, some nutrients can no longer be broken down and digested properly – this then causes the symptoms. However, food intolerance can also be triggered by food poisoning or a pseudoallergy. One usually speaks of a pseudoallergy when all external signs point to an allergy, but the immune system is not involved in the reaction – the body’s own defenses are not formed. In addition to these possibilities, psychological factors can also play a role in intolerance.

Food intolerance symptoms

The reactions to a food intolerance can be very different – the list of complaints is long. For this reason, we have summarized the most common symptoms here:

• shortness of breath
• stomach pain
• gas
• Diarrhea
• Vomit
• tachycardia
• itching
• headache
• fatigue
• sneezing attacks
• wheals
• constipation

However, probably the most serious reaction to a food intolerance is anaphylactic shock , because this circulatory collapse can be life-threatening.

The most common food intolerances at a glance

• Lactose intolerance is the most common food intolerance in the western world. Those affected lack the lactase enzyme, which is responsible for breaking down the lactose that has been absorbed. Even small amounts of cow’s milk can trigger gastrointestinal problems in those affected.
• In the case of fructose intolerance , the fructose is not sufficiently absorbed in the small intestine and some of it is transported to the large intestine, where it is broken down by the intestinal flora. The degradation products that are created in the process cause the typical symptoms in the gastrointestinal area, such as flatulence, bloating or diarrhea.
• Only one to two percent of the Western population suffer from histamine intolerance. The reason for the intolerance is an imbalance between the food component histamine and the degrading enzyme. This causes excess histamine to enter the bloodstream and “docks” to histamine receptors. This triggers allergy-like symptoms.
• Today, five to ten people in every 1,000 inhabitants are affected by celiac disease , including gluten intolerance . The gluten component gliadin triggers an immunological reaction in the mucous membrane of the small intestine, which leads to chronic inflammation and damage to the mucosa. The intestinal villi shrink over time and there is a lack of digestive enzymes.

Diagnosis of a food intolerance

• Avoidance diet: The avoidance diet is a reliable way of diagnosing an intolerance. Here, the presumably intolerable food is avoided for at least two to four weeks. If there is a visible improvement, the food is slowly added back to the diet – the effects are then documented in a food diary.
• H2 breath test: If there is a suspicion of a food intolerance, appropriate stress tests with the corresponding foods are usually carried out after an avoidance diet. In the H2 breath test, the respiratory gases are analyzed. Whether fructose or milk sugar: For the test, a solution of the intolerable sugar is drunk on an empty stomach. A measurement is then taken approximately every 30 minutes. If the hydrogen content of the breathing air increases by a certain percentage, the intolerance is considered confirmed.
• Blood tests: Only in the case of histamine intolerance is the definitive diagnosis made using a blood test. The activity of the degrading enzyme is measured. After the first blood draw, a two-week histamine-free diet follows, followed by another blood draw. If the values ​​improve and if the person concerned feels better, then the suspicion of an intolerance is confirmed.