Mouse study suggests popular sweeteners may affect metabolism across generations
A Chilean-led study in mice found that sucralose and stevia alter gut bacteria and gene activity, with some effects, especially from sucralose, persisting into later generations. The researchers stress the findings show associations, not proof of direct harm in humans.
Researchers from the Universidad de Chile have published a study in Frontiers in Nutrition examining how two widely used non-nutritive sweeteners, sucralose and stevia, affect mice across multiple generations. Lead author Dr. Francisca Concha Celume noted that despite growing consumption of such additives, rates of obesity and metabolic disorders like insulin resistance have not declined, prompting questions about their possible metabolic effects.
How the study worked
Forty-seven mice were divided into three groups, drinking either plain water, water with sucralose, or water with stevia, at doses meant to reflect realistic human consumption. These mice were bred for two further generations, which received only plain water. Each generation was tested for glucose tolerance, gut microbiome composition, short-chain fatty acid levels, and the activity of five genes in the liver and intestines linked to inflammation, gut barrier integrity, and metabolism.
Generational findings
In the first generation, impaired glucose tolerance appeared only in male offspring descended from sucralose-exposed mice. By the second generation, elevated fasting blood sugar was found in male descendants of the sucralose group and female descendants of the stevia group. Mice exposed to either sweetener developed more diverse gut microbiomes but with lower levels of beneficial short-chain fatty acids, a pattern that persisted into both later generations.
Sucralose produced stronger, more lasting effects, including greater shifts in microbiome composition, more potentially harmful bacteria, and fewer beneficial species. It also increased activity of inflammation-related genes and reduced metabolism-related gene activity, effects still detectable two generations later. Stevia's effects on gene expression were weaker and did not extend past the first generation.
Caveats
The researchers caution that the results show associations rather than proof that the sweeteners directly caused the changes, and that mouse biology may not translate directly to humans. None of the mice developed diabetes; the changes observed were subtle shifts in glucose regulation and gene activity. Concha said the goal is not to cause alarm but to encourage further research and reasonable moderation in consuming such additives.
