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Zero-calorie sweeteners could alter the genes of later generations, new study warns
By Deirdre Bardolf
Published April 17, 2026
Artificial sweeteners, present in everything from sugar-free snacks to diet sodas, are a staple for many trying to lose weight. But new research suggests the substances could have multigenerational effects, potentially altering metabolism in future generations even without direct consumption.
The findings raise questions about the long-term biological effects of widely used sugar substitutes, particularly as consumption has surged in recent years.
In a study published in the journal Frontiers in Nutrition, Chilean researchers found that mice given sucralose or stevia passed on changes in metabolism-related genes to their children and grandchildren even when later generations did not consume the sweeteners.
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The findings suggest the sweeteners may have triggered changes in gut bacteria and gene activity that were then passed down across generations of the mice.
While they do not prove the same thing happens in humans, the study adds to a body of research examining whether non-nutritive sweeteners really have no effect on the body, as many people believe.
Many Americans use zero-calorie sweeteners daily in drinks and foods. (iStock)
"When we compared generations, these effects were generally strongest in the first generation and tended to decrease in the second generation," lead author Francisca Concha Celume of the Universidad de Chile said in a statement.
The researchers divided 47 male and female mice into three groups.
One group received plain water, another received water with sucralose and a third received water with stevia. The doses reflected amounts humans might typically consume, according to the study.
Some 140 million Americans consume non-nutritive sweeteners regularly.
After 16 weeks, the mice were bred for two generations. The later generations received only plain water, but researchers still found changes in gut bacteria, lower levels of short-chain fatty acids, beneficial compounds that support metabolism and immune health, and shifts in genes linked to inflammation and metabolism, according to the study.
Sucralose, a popular no-calorie sugar substitute, appeared to have a stronger and more lasting effect, the researchers found. Approximately 140 million Americans consume non-nutritive sweeteners regularly, according to survey data cited by the researchers.
Male offspring of mice that consumed sucralose showed mild signs of impaired glucose regulation, while effects in females were more limited, the research said. Stevia's impact was smaller and appeared to fade sooner.
People commonly add artificial sweeteners to their coffee and tea. (iStock)
Concha Celume said the goal is not to alarm consumers but to push for more research into the long-term biological effects of these additives.
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"What we observed were subtle changes in how the body regulates glucose and in the activity of genes associated with inflammation and metabolic regulation," she said.
"It is possible that such changes could increase susceptibility to metabolic disturbances under certain conditions, such as a high-fat diet."
"We don't have equivalent human data yet, but the precautionary principle applies here."
Concha Celume said it's worth noting that as artificial sweeteners have grown more popular, obesity and metabolic problems haven't declined.
While that doesn't mean the sweeteners are to blame, she said it raises questions about how they might affect the body.
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"It may be reasonable to consider moderation in the consumption of these additives and to continue studying their long-term biological effects," she added.
Sucralose is an artificial sweetener. Stevia is derived from a plant. (iStock)
Even though the study was conducted in mice and its findings cannot be directly applied to humans, it is worth taking seriously, according to Kristen Kuminski, a New York-based registered dietitian nutritionist specializing in metabolic health, weight management and nutrition support for people using GLP-1 medications.
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Outside experts say the findings, while limited to mice, align with growing concerns about how artificial sweeteners may affect the body.
"The mechanisms it's pointing to, specifically gut microbiome disruption and epigenetic changes, are plausible in humans and align with what we're already seeing in the broader sweetener research," Kuminski told Fox News Digital.
Sugar substitutes are widely used for weight management, but researchers are studying their potential health effects. (iStock)
She said it's not surprising that sucralose showed stronger effects than stevia.
"Stevia is plant-derived and metabolized differently than sucralose, which passes through the gut largely unchanged and has more direct contact with gut bacteria," Kuminski said.
For consumers, the most reasonable takeaway is moderation, Kuminski agreed.
"Sucralose and stevia have been rigorously evaluated by food safety authorities."
"For most people, reducing sucralose specifically and leaning toward whole food sources of sweetness is a reasonable takeaway from this research," she said. "Stevia in moderation appears to be the lower-risk option if a zero-calorie sweetener is something someone relies on regularly.
"The multigenerational piece is the part that should give people pause, particularly anyone who is pregnant or planning to be. We don't have equivalent human data yet, but the precautionary principle applies here."
Moderation is recommended when it comes to artificial sweeteners in drinks, an expert told Fox News Digital. (iStock)
The International Sweeteners Association (ISA), based in Brussels and representing suppliers and other stakeholders, said the study does not change existing safety conclusions for sweeteners such as sucralose and stevia.
"Sucralose and stevia have been rigorously evaluated by food safety authorities and approved for use in food and drinks within their acceptable daily intake," the group said in a statement on its website.
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The ISA also noted that because later generations of mice were never directly given the sweeteners, it's unclear whether the changes were passed down through gut bacteria or through other biological mechanisms.
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"Results from animal experiments, particularly those focused on the gut microbiome, are of limited relevance to human health," the group added.
Fox News Digital reached out to the ISA and the study authors for additional comment.
https://www.foxnews.com/food-drink/zero-calorie-sweeteners-could-alter-genes-later-generations-new-study-warns