Extract of a book by Giulia Enders entitled: "The discreet charm of the intestine"
Malabsorption of fructose, a sugar found especially in fruits. As for lactose intolerance, this intestinal functional disorder also exists in a severe congenital form: fructose (or hereditary fructose intolerance), which generates digestive problems from the smallest amount of fructose absorbed. Most people, however, suffer rather from a problem due to excess fructose. We often do not really know what it is and on the packaging of food products, the mention "contains fructose" gives us the impression of buying a product better for health than if it contained "sugar ". The food industry is therefore happy to add pure fructose to its products and also contributes to making our diet richer in fructose than ever before. For many, one apple a day is not a problem - if there was not also ketchup on fries, sweet yoghurt with fruit and brick soup that all contain fructose. Or some tomatoes, specially grown to develop a high proportion of fructose. To top it off, today we face a supply of fruits that, without globalization or air transport, would not exist anywhere on the planet. In winter, pineapples from tropical countries meet on our stalls with fresh strawberries from Dutch greenhouses and some dried figs from Morocco. What we are entering into the category of food intolerance, therefore, is perhaps the wholesome response of a body that, within a generation, has had to adapt to a diet such as it has never existed before. The mechanism behind fructose intolerance is not the same as for gluten or lactose. People with congenital intolerance have few enzymes in their cells that allow fructose assimilation. Fructose can therefore be concentrated little by little in cells and hinders other processes. In the case of a sensitivity that develops later, it is assumed that the problem lies rather in the transport. In these patients, the transport channels of fructose (the GLUT-5 transporters) are often fewer When they ingest a small amount of fructose - for example by eating a pear, the transport channels are immediately saturated and the sugar of the pear, following the same pattern as in a lactose intolerance, joins the intestinal flora, in the large intestine. Today, some researchers wonder if the reduced number of transport channels is really at the root of the problem, since subjects without digestive disorders also send some of the undigested fructose into the large intestine. So why does fructose cause trouble for some and not for others? One of the probable causes is in the composition of the intestinal flora. Our pear eater sends excess fructose to a certain class of intestinal bacteria, which use it to generate a whole bunch of annoying symptoms. A phenomenon that increases in proportion to the amount of ketchup, fruit yogurt or brick soup that has been swallowed before. When fructose is poorly absorbed, morale can even take a hit too. Thanks to sugar, many other nutrients are assimilated into the blood. The amino acid tryptophan, for example, likes to bind to fructose during digestion. But if the amount of fructose we have in the belly is too important to be assimilated as a whole, we get rid of it and lose at the same time the one who clung to his sneakers: tryptophan. Tryptophan is also useful for producing serotonin. Serotonin is the neurotransmitter that is also called "the hormone of happiness" because a deficiency can cause depressions. Undetected, a malabsorption of fructose that lasts for several years can therefore be quite the cause of depressive moods. This is a recent discovery that is slowly making its way into medical practices.
For more information, here is a very interesting book by Giulia Enders entitled: - The discreet charm of the intestine: All about an unloved organ of the body