The use of sweeteners causes harm that is passed on to children, a study with mice reveals

The research, carried out by the University of Chile and published this Friday in the magazine Frontiers in Nutritionhas discovered that these natural sugar substitutes alter the intestinal microbiota and modify the expression of genes linked to metabolism and inflammation.

Although new studies are needed to confirm that these results can be replicated in humans, the authors advise moderating the consumption of these additives while their long-term biological effects on the body are studied in depth.

Artificial sweeteners are synthetic sugar substitutes that are much sweeter and have hardly any calories, which is why they are often used to lose weight or control diabetes.

However, “we found it intriguing that despite the growing consumption of these additives, the prevalence of obesity and metabolic disorders such as insulin resistance has not decreased,” comments Francisca Concha Celume, researcher at the University of Chile and lead author of the work.

To find out how sweeteners influence metabolism, the team divided 47 mice – male and female – into three groups: one received water alone, another water with sucralose, and the third water with stevia, in an amount comparable to what a human would drink on a normal diet.

The mice were bred for two consecutive generations that received only water and underwent an oral glucose tolerance test to assess insulin resistance (an indicator of diabetes).

They also took fecal samples to look for changes in the gut microbiome and concentration of short-chain fatty acids, and analyzed the expression of five genes involved with inflammation, intestinal barrier function, and metabolism in the liver and intestines.

The team observed that the sweeteners produced different effects, which changed over time.

In animals of the first generation, only the male offspring of the mice that took sucralose showed signs of glucose intolerance.

But in the second generation, they observed that the effect persisted and diversified, so that the grandsons of the group of males who consumed sucralose and the granddaughters descended from the females who consumed stevia recorded elevated fasting blood sugar levels.

The explanation seems to be in the microbiome. By analyzing the fecal samples, they discovered that the two groups of mice that took sweeteners had more diverse fecal microbiomes but with lower concentrations of short-chain fatty acids, molecules produced by bacteria that are essential for regulating inflammation and the intestinal barrier.

But the effects of sucralose were more persistent. This sweetener not only altered the intestinal flora, favoring the appearance of pathogenic bacteria, but also increased the expression of genes linked to inflammation and attenuated that of genes linked to healthy metabolism in the two generations following consumption.

And although stevia also showed effects on gene expression, they were minor and were only transmitted to one generation.

“When comparing the generations, these effects were generally stronger in the first generation and tended to decrease in the second” and in general, “the effects linked to sucralose were more consistent and persistent across generations,” concludes Concha Celume.

Despite these results, the mice in the study did not develop diabetes spontaneously but rather showed “early biological signals” that could make them more susceptible to metabolic alterations if combined with other conditions “such as a high-fat diet,” he points out.

However, the team stresses that although the research identifies associations in animal models, the impact of non-nutritive sweeteners in mice will not exactly mirror their impact in humans.

The objective of the study “is not to create alarm,” but to highlight the need to continue investigating the long-term biological effects of artificial sweeteners, concludes the researcher.