Acquired fructose intolerance: symptoms
Bloating and diarrhea are the most common symptoms of acquired fructose intolerance. Other symptoms such as abdominal cramps may also occur. Often, a resulting lack of nutrients as well as concomitant diseases also cause discomfort to those affected.
Leading symptoms
In acquired fructose intolerance (fructose malabsorption), the body can absorb fructose only to a limited extent or not at all in the small intestine. The fructose enters the large intestine, where it 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 allow water to flow into the bowel. This causes the stool to liquefy and the affected person to develop diarrhea.
These two fructose intolerance symptoms – flatulence and diarrhea – are considered the leading symptoms of the disease. Nevertheless, they do not occur in every affected person!
In addition, there are other fructose intolerance symptoms that affect the digestive tract. They resemble the symptoms of irritable bowel syndrome and are therefore often not interpreted correctly. They include:
- Abdominal pain (preferably in the lower abdomen)
- Abdominal cramps
- Nausea
- Feeling of fullness
- loud audible bowel sounds
- sudden urge to defecate
- soft stool
- accumulation of mucus on the stool
- constipation (often after preceding diarrhea)
What affects fructose intolerance symptoms
People with acquired fructose intolerance usually still tolerate small amounts of fructose. Only when the individual tolerance limit is exceeded do symptoms occur. The symptoms mentioned above can vary and are subject to certain influencing factors.
Food composition
The combination with glucose is also beneficial for tolerance. This is also the reason why those affected are often better able to absorb fructose in the form of household sugar (sucrose), which consists of half fructose and half glucose.
Intestinal flora
Since intestinal bacteria are fundamentally involved in the formation of gas in fructose intolerance, problems are exacerbated if an unusually large number or the wrong bacteria colonize the intestine. Normally, there are many more bacteria in the large intestine than in the small intestine. They are necessary for normal digestion. So, in the large intestine, intestinal gases are naturally produced, which we normally do not perceive as burdensome.
Folic acid and zinc deficiency in fructose intolerance
Symptoms of acquired fructose intolerance can manifest themselves not only acutely, but also in the long term. In many people with fructose malabsorption, the unabsorbed fructose accumulates in the intestine. In addition, the colonization of intestinal bacteria often changes. These factors influence the intestinal flora and can have a negative effect on the absorption of vitamins and trace elements. The result is often a folic acid and/or zinc deficiency.
Folic acid
Among other things, the vitamin folic acid is involved in cell formation and regeneration as well as blood formation and is necessary for various metabolic processes. It is found, for example, in green leafy vegetables, nuts, legumes, liver and yeast.
If pregnant women suffer from a folic acid deficiency, the child’s nervous system may form defectively (neural tube defect).
Zinc
Symptoms of zinc deficiency are often observed in people with acquired fructose intolerance. Zinc is one of the most important trace elements and is involved, among other things, in various metabolic processes and the regulation of the immune system. With a deficiency, one is therefore more susceptible to infections. In addition, wound healing may be impaired. Other possible symptoms of zinc deficiency are loss of appetite, hair loss and diarrhea.
Good sources of zinc include nuts, eggs, milk, beef and pork.
Concomitant diseases in fructose intolerance
Also due to an undersupply of certain messenger substances, the symptoms of a fructose intolerance can appear or intensify under certain circumstances.
Compared to the healthy normal population, people with fructose malabsorption also suffer from depression significantly more often. Presumably, this has to do with a tryptophan deficiency: In the case of fructose intolerance, the body absorbs this protein building block (amino acid) less easily because it is bound by the fructose present in the intestine. However, tryptophan is necessary for the formation of the neurotransmitter serotonin. In depression, the serotonin concentration in the brain is often measurably lower.
A serotonin deficiency often causes a craving for sweets. Sugar actually improves the transport of tryptophan into the brain – unless it is fructose in the case of fructose intolerance. This can increase fructose intolerance symptoms.
Hereditary fructose intolerance: symptoms
In addition, hereditary fructose intolerance causes chronic symptoms such as loss of appetite and failure to thrive, as well as liver failure and kidney damage. However, if the inborn error of metabolism is detected early (in babies) and taken into account in the diet, these serious consequences can be avoided.