Sometimes in the field of medicine unthinkable paradoxes are revealed, which undermine all the previous certainties on which behaviors, prescriptions and therapeutic guidelines were based. This is the case. Recent studies conducted this year, the most important of which published in Nature, show that the use of non-calorie artificial sweeteners determines alterations in a series of metabolic parameters attributable to glucose intolerance and insulin resistance.
The sweeteners put under the magnifying glass are aspartame and saccharin, therefore the most common sugar substitutes, widely used and, so far suggested, precisely for the diabetic population. On the market there are numerous lines of confectionery bakery products based on these sweeteners, with the aim of making otherwise banned foods accessible even to diabetics. In reality, artificial sweeteners have spread on a large scale especially to reduce calorie intake as a function of dietary measures in slimming diets; their use has become a frequent habit for those who are attentive to the figure, in the belief of exercising a correct habit by substituting them for sugar.
Aspartame
Since it was introduced on the market in 1965, aspartame has always aroused suspicion and concern. Many in-depth studies have been conducted to demonstrate the absence of harmfulness and allow aspartame to remain on the market. In particular, the metabolism of the substance has always been indicated as a possible critical point. In fact, in the liver, aspartame is broken down into its main elements: phenylalanine, aspartic acid and methanol. The latter has always been indicted as the toxic molecule, since, in the liver, it is converted into formic acid, a highly dangerous compound for the development of metabolic acidosis and liver failure.
The commercial fortune of aspartame(indicated with the initials E951) derives precisely from its intrinsic characteristics: in fact, discovered by chance by the chemist James Schlatter, it seems to respond exactly to all the needs that the food industry market presents and fully satisfies the demand for low cost by the diabetic and non-diabetic population. With a sweetening power 160-220 times greater than sucrose and a caloric intake is more or less equivalent (4 Kcal / gram, like any protein), very few quantities of aspartame sweeten food and drinks in a pleasant way. Furthermore, aspartame has the great advantage of not altering blood sugar, not following the metabolic pathway of glucose (it is a dipeptide and not a disaccharide like sucrose). It is acaryogenic, unlike sucrose. In addition, it has a high heat stability,It is contraindicated in pregnancy and lactation since small quantities also cyclize spontaneously and diketopiperazine is toxic to the fetus and newborn.
Saccharin
Saccharin has an older history than aspartame: it was discovered in 1878 by chemists Remsen in Fahlberg. It exists in three forms: saccarific acid, sodium saccharin (the most common) and calcium saccharin. It has a sweetening power 200-600 times greater than sugar, with a bitter-metallic aftertaste in high doses. It is often used in association with cyclamate, to correct the respective defective aromas. It is also sometimes used in combination with aspartame. It has a very high stability to Ph and temperature variations.
Saccharin is 90% absorbed and not metabolised by humans, it is excreted unchanged in the urine. It is totally acaloric and acaryogenic. In fact, it appears that saccharin is not quite an inert molecule. Some studies speculate that it may interfere with some enzymatic properties of glucose-6-phosphatase, the enzyme that allows free glucose to return to the bloodstream. This thesis has never been confirmed and there are no known interactions whatsoever between insulin and saccharin.
It has been the subject of studies in the hypothesis that it was carcinogenic especially towards the cells of the bladder, without ever reaching definitive conclusions. Caution is recommended in pregnancy as it crosses the placenta.
The experimental study
The largest and most reliable study is an experiment by an Israeli group, conducted on laboratory animals and subsequently on humans. The researchers evaluated large case series based on a diet containing sweeteners (aspartame or saccharin), closely monitoring them with a sensor that detected blood sugar every 5 minutes.
The aim of the work is to clarify how sweeteners expose diabetes to risk, for prolonged use and for large doses, since the mechanisms must be completely different from those that follow sucrose. In fact, it is known that artificial sweeteners are non-saccharide molecules and therefore do not follow the glucose pathway nor are they directly connected with insulin stimulation.
The study shows that artificial sweeteners select a bacterial population that promotes greater absorption of carbohydrates and greater conversion of sugars into fats. In the long run, the modification of the intestinal microbiota favors the clinical condition of diabetes, but probably also of neoplasms or inflammatory bowel diseases.
It is known that there is proportional decrease of intestinal bacterial populations belonging to Firmicutes and Bacteroides, respectively, in subjects with type 2 diabetes and obese. Other studies reveal that 12 weeks of a sucralose-rich diet reduces the number of colonies of commensal bacteria such as Bifidobacterium, Lactobacillus and Bacteroides in rats. These changes in the intestinal environment have been correlated with the development of insulin resistance, hyperglycemia, increased adipose tissue deposition, and low-grade inflammation.
No alarmism
These studies represent an important scientific contribution to clarify the advantages and disadvantages of the use of sweeteners in the diet. However, before becoming a nutritional recommendation and being translated into clinical practice it will be necessary to wait for further confirmation. The reckless use of sweeteners for drinks or products containing sweeteners has always been advised against by the most authoritative Scientific Diabetes Societies, rather it has encouraged the re-education therapy of these patients aimed at correcting the perception of excessive sweet taste and converting their own food choices towards natural flavors.
