The mice stopped drinking sweetened water, but their bodies did not fully reset.
In a study published in Frontiers in Nutrition on April 10, 2026, researchers at the University of Chile found that both sucralose and the plant-derived sweetener stevia left metabolic and microbial fingerprints that carried into offspring who had never tasted the sweeteners themselves.
The lead group drank plain water dosed with sucralose or stevia at levels comparable to normal human intake. Two later generations received only water. Even so, glucose regulation and gut chemistry stayed altered.
What the study did
The team followed 47 C57BL/6J mice, split into three groups, across 16 weeks of exposure and two follow-up generations.
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They tracked oral glucose tolerance, sampled the gut microbiome, measured short-chain fatty acids (the beneficial compounds gut bacteria produce from fiber), and read gene activity in liver and intestine.
Male offspring of sucralose-exposed mice showed impaired glucose tolerance in the first generation.
In the second generation, elevated fasting blood sugar appeared in males from the sucralose line and in females from the stevia line. Both sweeteners lowered short-chain fatty acid levels and shifted inflammatory gene expression in the gut.
"Overall, the effects linked to sucralose were more consistent and persistent across generations," lead author Francisca Concha Celume, of the University of Chile, said in a statement released with the study.
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Stevia produced weaker signals, and most of its effects were largely normalized by the second generation.
The researchers do not claim direct harm to humans. "The goal of this research is not to create alarm, but to highlight the need for further investigation," Concha added.
Where human evidence stands
This is an animal study, and mouse metabolism does not map one-to-one onto human physiology. But the results line up with a wider trend in the literature.
A review from the Friedman School of Nutrition Science and Policy at Tufts University, published on June 30, 2026, pooled 21 randomized clinical trials in adults.
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Compared with non-caloric controls such as water or placebo, low-calorie sweeteners raised fasting insulin and HbA1c, a marker of longer-term blood sugar, with a trend toward worse insulin sensitivity. Our earlier coverage summarized what WHO and the Tufts trial review actually found.
"When pooling findings from individual trials, we see signals that these compounds may have metabolic harms," said Meng Wang, a research assistant professor at the Friedman School.
The clinical takeaway remains cautious. "Until we know more, caution is needed," said Dariush Mozaffarian, director of the Food is Medicine Institute at Tufts. "If you're replacing large amounts of added sugar in your diet, such as in multiple servings of soda, these low-calorie sweeteners may be a better alternative."
What it means in practice
In 2023 the World Health Organization recommended against using non-sugar sweeteners, including sucralose, for weight control or to reduce chronic disease risk.
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Its review concluded the sweeteners do not confer a long-term benefit in reducing body fat in adults or children. The guidance is classified as conditional, meaning countries are asked to weigh it against local context.
Zero calories is not the same as zero metabolic activity. The Chile group calls for follow-up work, including in humans, to see whether any of the intergenerational signals seen in mice translate at all to people.
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This article is made and published by Ida-Marie Palm Varbæk, who may have used AI in the preparation.