Two of the world's most common zero-calorie sweeteners may leave a biological trace that lasts well beyond the sweetness on the tongue, according to a mouse study published in Frontiers in Nutrition. Sucralose and stevia both altered the gut microbiome and gene activity of exposed animals — and in sucralose's case, some of those changes turned up in offspring and grand-offspring that had never consumed the sweetener themselves.
Researchers led by Francisca Concha Celume of Chile's Universidad de Chile divided 47 mice into three groups — plain water, sucralose or stevia — and bred them across two further generations, with only the original animals ever exposed to the sweeteners. Both groups showed reduced levels of short-chain fatty acids, byproducts of healthy gut bacteria linked to metabolic health, a decline that persisted into later generations.
Sucralose produced the more lasting effects. Mice given the artificial sweetener carried a more diverse but more pathogen-heavy gut microbiome, and genes tied to inflammation and metabolism stayed altered for two generations after exposure. First-generation males exposed to sucralose developed impaired glucose tolerance, and elevated fasting blood sugar later showed up in second-generation sucralose-lineage males and, separately, stevia-lineage females. Stevia's own genetic effects were milder and did not carry past the first generation, as summarized in coverage from ScienceDaily.
"[The findings] highlight the need for further investigation," and suggest people consider "moderation in the consumption of these additives."
Francisca Concha Celume, Universidad de Chile, via Science Media Centre
The study, conducted in mice rather than humans, does not prove the same multigenerational pattern would occur in people, and the researchers stopped short of recommending anyone change their diet. But it adds to a growing body of research questioning whether non-nutritive sweeteners — found in diet sodas, "sugar-free" snacks and tabletop packets worldwide — are the metabolically neutral swap they are often marketed as. Follow-up work in mammals closer to humans, the authors said, is the logical next step.
