New research adds to growing concerns about the long-term health effects of popular zero-calorie sweeteners. A study published in Frontiers in Nutrition found that sucralose and stevia — two of the most widely consumed non-nutritive sweeteners — altered gut microbiomes and metabolic gene activity in mice, with some changes persisting for two generations after the original exposure ended.

The research team divided 47 mice into three groups: one received plain water, while the others consumed water containing either sucralose or stevia at doses comparable to normal human dietary intake. The mice were then bred for two successive generations, with the offspring receiving only plain water.\n First-generation offspring of sucralose-consuming mice showed signs of impaired glucose tolerance. By the second generation, elevated fasting blood sugar appeared in male sucralose descendants and female stevia descendants. Both sweeteners produced more diverse fecal microbiomes but with lower levels of short-chain fatty acids — compounds produced by gut bacteria that influence gene regulation and metabolic health.

Sucralose showed stronger and more persistent effects: it increased the activity of genes linked to inflammation while reducing metabolic gene activity, changes still detectable two generations after exposure. Stevia altered gene expression too, but the changes were weaker and did not persist beyond one generation.

Lead author Dr. Francisca Concha Celume of the Universidad de Chile emphasized the findings raise questions about why obesity and metabolic disorders have not declined despite growing sweetener consumption. The researchers caution the results are from mice and do not prove direct causation in humans, but argue they highlight the need for further investigation into long-term biological effects.

Sources