Why do tropical fruits not contain fructose

Fructose Intolerance: Recognize Signs & Relieve Discomfort

Fructose and fructose intolerance: what exactly is it?

Fruit sugar, known as fructose, is a simple sugar that is naturally found primarily in honey and fruit. Dextrose, known as glucose, is also a simple sugar, but with less sweetening power. Ordinary household sugar also contains fructose and glucose - each with a share of 50 percent. The healthy reputation of fructose has been shaken for a long time, especially due to the production of the industrial, highly concentrated fructose syrup, which is used in numerous drinks and finished products and has been shown to play a major role in common diseases such as diabetes.

Those who consume too much of it can suffer from fructose malabsorption for a short time. However, this is more likely to be attributed to a total intestinal overload and not to be confused with intolerance. And the same applies to intolerance to fructose: not all fructose intolerance is the same. From a medical point of view, a distinction is made between two types - hereditary and intestinal fructose intolerance.

Hereditary fructose intolerance

Hereditary fructose intolerance (HFI) is an inherited metabolic disorder in which the body lacks the enzyme adolase B, which is responsible for breaking down fructose. Since breast milk does not contain fructose, the first symptoms usually appear after weaning, when babies suffer from diarrhea and vomiting. If the intolerance is not treated, it can have serious consequences: intestinal and stomach problems, apathy, hypoglycaemia, seizures and even severe kidney and liver damage. Fortunately, inherited fructose intolerance is not common, but sufferers must not consume fructose for their entire life.

Intestinal fructose intolerance

Much more common than the hereditary variant is intestinal fructose intolerance (IFI), in which the absorption of fructose into the blood is disturbed. What happens with this resorption disorder in the intestine? Normally, certain transport proteins - the so-called GLUT-5 - ensure that the fructose from the food reaches the bloodstream via the mucous membrane of the small intestine. If this transport does not work well, sugar molecules remain in the intestine and slide deeper and deeper there. It is only in the large intestine that bacteria ensure that the fructose is broken down - but the gases produced are anything but pleasant for those affected. And the water-binding property of fructose, which ensures that no liquid is removed from the food pulp, causes unpleasant complaints. Since the performance of this transport system is different for every person, there are different forms of fructose intolerance. While many people can still consume fructose in moderate amounts, others suffer from symptoms after just one bite.

The researchers do not yet agree on the causes of the IFI. Triggers can be infections in the stomach and intestines, the use of antibiotics or other drugs that put strain on the digestive tract. Or fungal infection that attacks the intestinal flora. In addition, chronic stress such as stress, an unhealthy diet and the excessive consumption of fructose also play a major role.