Sacrin and other artificial sweeteners modify the intestinal flora in a way that facilitates weight gain, makes it difficult to control the blood sugar level and increases the risk of type 2 diabetes. It is the conclusion of an investigation of the Weizmann Institute of Removot(Israel) presented in the journal Nature and that will force to reconsider the massive use of artificial sweeteners in the food industry.
"Our results indicate that artificial sweeteners induce the same problems they intend to prevent," said Elinav, co -director of the investigation, at a telephone press conference.But he adds that these results "are not the last word" on the issue, but the first, so "it would be premature to make general recommendations on the consumption of sweeteners."
Unlike sugar, artificial sweeteners usually pass through the digestive system without being digested.For this reason they do not contribute calories.But for this same reason they reach intact to the intestinal flora-the bacteria that populate the large intestine.
Since the foods that we eat regulate the intestinal flora, and since the intestinal flora regulates health, the researchers wondered if the artificial sweeteners could have some relevant effect.
To find out, they conducted a series of experiments in mice and "we were surprised that the effect was so large," said they were segal, also co -director of the investigation of the Weizmann Institute.Subsequently, they conducted two studies in people who confirmed the results.
The experiments in mice have shown that, when an animal ingests saccharin, aspartamo or sucralous, the blood sugar level rises more than when it ingests sugar.
They have also shown that sweeteners modify the composition of the intestinal flora.Specifically, they reduce the bacteria of the Bacteroid genus- which are an antidote against obesity- and increase those of the genus firmicutes.
To make sure that the intestinal flora is the key to the effect of the sweeteners on the blood sugar level, they have performed a transplant of intestinal bacteria of mice fed with mice that had never taken saccharin.The results have dissipated doubts: after the transplant, the blood sugar level has been shot.
In people, the results have been equally significant.In a first study, the consumption of artificial sweeteners has been evaluated in a sample of 381 people who answered a nutritional survey.The answers have revealed that, the more frequent the consumption of saccharin, the greater the weight of a person and the higher the blood sugar level is usually.In addition, the most kilos tend to accumulate in the abdomen, which is where they are more harmful to health.
When performing blood tests to the usual saccharin consumers, abnormally high levels of glycosylated hemoglobin (which indicates the concentration of blood sugar in the previous three months) and the enzyme alt (indicating the liver damage and thatResearchers attribute to a fatty liver disorder).
In a second study, seven healthy people who were not regular consumers of artificial sweeteners have agreed to take 360 milligrams of saccharin for a week, a dose considered acceptable by the US food and drug agency.
Towards the end of the week, four of the seven participants in the study had altered their ability to regulate the blood sugar level.The composition of its intestinal flora has also been altered throughout the week.In the other three participants, saccharin has had no harmful or beneficial effect.
An analysisRetrospective has revealed that, since before starting the experiment, the four people harmed by saccharin had a composition of the intestinal flora different from that of the other three people.
"Not everyone responds negatively to artificial sweeteners," they said were segal.But "they can be harmful to a broad sector of the population."For now there is no tests that allow to know who they are harmless and for whom harmful.
"It is a very surprising and interesting investigation," says Francisco Guarner, director of the Digestive System Unit at the Vall d’Hebron hospital and researcher specializing in intestinal flora.Guarner remembers that previous investigations had shown that the bacteria of the digestive system play an important role in type 2 diabetes and in obesity.But "the influence of artificial sweeteners is an important novelty that can affect a large number of people."
The investigation has been limited to three of the most consumed artificial sweeteners.The three affect the ability to regulate the level of blood sugar and the risk of diabetes, although saccharin has a harmful effect more pronounced than the aspartamo and the sucralose.
When researchers have been asked if other sweeteners such as Stevia may have a similar effect, researchers from the Weizmann Institute have avoided ruling."We have not analyzed the Stevia and we cannot speculate on sweeteners that have not been studied, because different intestinal floors react differently from different sweeteners," they said were Elinav.The Stevia is also a sweetener of natural origin, while saccharin, aspartamo and succral are artificial.But "our results invite these studies to be done."
They have also avoided ruling on whether sugar is better that artificial sweeteners because "in no way we want to give entity that sugar drinks are healthy and should recover," they added were segal.
It will predictably open a new phase of research on sweeteners in which its effects on intestinal flora will be taken into account.These investigations will be aimed at looking for molecules that do not have the disadvantages of sugar or those of saccharin.
With the data available so far, "we do not believe that there is sufficient basis to change dietary recommendations," Elinav warned.But he has admitted that "for years I have been drinking large amounts of coffee and consuming sweeteners thinking that they were not harmful and personally I have made the decision to stop consuming them."
The results of the research "demand a reevaluation of the massive use of artificial sweeteners," conclude the scientists of the Weizmann Institute in Nature.
