New study suggests zero-calorie sweeteners aren’t so sweet

Artificial sweeteners are the reason your soda can taste sweet without the sugar (or the guilt).

But that swap might not be as harmless as it sounds.

A new study on mice suggests artificial sweeteners could have serious long-term effects on the gut microbiome and gene activity, with the potential to stick around across multiple generations—even if offspring don’t consume sweeteners.

Of mice and sweeteners

The scientists in the study began by splitting mice into three groups, each of which received either plain water, sucralose, or stevia at doses similar to what humans consume.

• They then bred them for two generations, with all future mice drinking only plain water.
• The researchers tracked things like blood sugar, gut bacteria, and gene activity across each generation.

What they found: Both sweeteners changed gene activity tied to metabolism and inflammation, with mice exposed to them also showing shifts in their gut microbiome, a key player in digestion and overall health.

But sucralose stood out even compared to stevia, with its effects sticking around longer and showing up even in generations of mice who were never directly exposed.

The results suggest artificial sweeteners—especially sucralose products—may trigger changes that affect how the body processes sugar over time, which can last beyond a single lifetime, researchers say.

There is a catch: This study shows a link, not proof of cause and effect, and was also only done in mice. The researchers say further investigation is needed to determine the exact effects of artificial sweeteners in humans.

Big picture: Artificial sweeteners and additives aren’t just in diet soda or coffee; they show up in ~60% of packaged foods across the US. This includes everyday items like bread, ketchup, cereals, and snack foods, often replacing or supplementing real sugar to reduce calories.