Fructose intolerance – symptoms

Fructose intolerance: leading symptoms

In fructose intolerance, fructose can be absorbed only to a limited extent or not at all in the small intestine. It enters the colon and is decomposed by bacteria. This produces hydrogen, carbon dioxide and short-chain fatty acids. The gaseous carbon dioxide can accumulate in the intestine and cause flatulence. The short-chain fatty acids lead to a flow of water into the intestine. As a result, the stool liquefies and causes diarrhea.

The fructose intolerance symptoms flatulence and diarrhea are therefore among the so-called leading symptoms of the disease. Nevertheless, they occur only in about every second person with a fructose incompatibility.

In addition, there are other fructose intolerance symptoms that affect the digestive tract. They are similar to the symptoms of irritable bowel syndrome and are therefore often not interpreted correctly. These include:

• Abdominal pain (preferably in the lower abdomen)
• Stomach cramps
• nausea
• bloating
• Loud audible bowel sounds
• Sudden urgency
• Soft chair
• Slime storage on the chair
• Constipation (often after a previous diarrhea)

What influences fructose intolerance symptoms?

Fructose intolerance patients usually tolerate small amounts of fructose. Only when their individual limit is exceeded, complaints occur. The above symptoms may vary and are subject to certain factors.

Food composition
If foods with a high proportion of fructose, such as fruits, fruit juices or drinks with the sugar substitute sorbitol, are used, complaints occur more frequently. On the other hand, if fructose is part of household sugar, it can be better absorbed. For meals with low fat and protein content also causes faster complaints.

intestinal flora
As gut bacteria are fundamentally involved in gas formation in fructose intolerance, the problems increase when many bacteria colonize the gut. Normally, there are many more bacteria in the colon than in the small intestine. They are necessary for normal digestion. In the large intestine so naturally intestinal gases, which are not perceived as stressful. If, on the other hand, the bacteria in the small intestine multiply, more gases are already being formed here. This is not the normal digestive process and can cause discomfort.

Folic acid and zinc deficiency in fructose intolerance

Symptoms of fructose intolerance can not only be acute, but also long term. In many people with a fructose intolerance, the unrecorded fructose accumulates in the intestine. In addition, an altered colonization with intestinal bacteria often occurs. These factors affect the intestinal flora and may affect the absorption of vitamins and trace elements. In particular, a folic acid or zinc deficiency is observed.

The vitamin folic acid is mainly found in green vegetables, nuts, beans, liver and yeast. It is necessary for various metabolic processes. In the case of fructose intolerance, sometimes too little folic acid is absorbed from the intestine. A folic acid deficiency can lead to anemia (anemia). If pregnant women suffer from a folic acid deficiency, the formation of the nervous system can be faulty (neural tube defect).

In addition, a lack of zinc was observed in connection with fructose intolerance. People with a zinc deficiency are more likely to suffer from infections.

Concomitant diseases with fructose intolerance

Not only can symptoms appear as a result of fructose malabsorption, but they can also be signs of concomitant disease. The Journal of Nutritional Medicine estimates that over 80 percent of patients with intolerance to lactose (lactose intolerance) also suffer from fructose intolerance (as of 2000). The symptoms of both diseases overlap. However, they require different treatment measures.

Compared to the healthy normal population, people with fructose intolerance are much more likely to suffer from depression. It is believed that this has to do with a tryptophan deficiency. The amino acid tryptophan is contained in proteins and is inferior to the fructose intolerance. The messenger serotonin is produced from tryptophan. It is of great importance both in the intestine and in the nervous system. In depression, lower serotonin concentrations in the brain are measured.

In addition, a serotonin deficiency often causes a sweet tooth. As a result, if a person takes sugar, the tryptophan transport into the brain actually increases. However, when sugar is added as fructose, fructose intolerance symptoms may increase.

Hereditary fructose intolerance: symptoms

In contrast to the mostly harmless symptoms of fructose malabsorption, fructose intake in hereditary fructose intolerance can have serious consequences. In addition to nausea and vomiting, sufferers are often significantly hypoglycemic. This can cause concentration problems, headaches, dizziness and even fainting. In hereditary fructose intolerance, there is an enzyme deficiency. This enzyme is also found in the liver and kidney. If affected persons come into contact with fructose, these organs can be damaged in addition to the small intestine. Since it is an inborn metabolic disease, these can Fructose intolerance symptoms already appear in infants.