• Posted September 4, 2025

Sugar Substitutes Could Be Bad For Brain Aging, Study Argues

Artificial sweeteners like Equal and Sweet’N Low might help you cut calories, but it might be at the cost of future brain power, according to a new study.

People who consume high amounts of low- and no-calorie sugar substitutes appear to experience faster declines in thinking and memory skills, researchers reported Sept. 3 in the journal Neurology.

Their decline is 62% more rapid than among people consuming the least amounts – equal to about 1.6 years of additional brain aging, results showed.

This link was even stronger in middle-aged folks and people with diabetes, researchers found.

“Low- and no-calorie sweeteners are often seen as a healthy alternative to sugar,” senior researcher Dr. Claudia Kimie Suemoto, an associate professor of geriatrics at the University of São Paulo in Brazil, said in a news release. “However, our findings suggest certain sweeteners may have negative effects on brain health over time.”

For the study, researchers tracked the health of nearly 12,800 adults in Brazil. Their average age was 52, and they were followed for an average of eight years.

Participants completed diet questionnaires at the start of the study, allowing researchers to estimate their intake of aspartame (NutraSweet, Equal), saccharin (Sweet'N Low), acesulfame-K, erythritol, xylitol, sorbitol and tagatose.

The study did not track the use of sucralose, the sweetener marketed as Splenda.

Some of these sweeteners can be found in the usual blue or pink packets provided in restaurants. They also are used to flavor ultra-processed drinks, desserts and foods.

The research team divided participants into three groups based on the total amount of sugar substitutes consumed.

They then compared that consumption to participants’ performance on tests of memory, language and thinking skills.

People who consumed more artificial sweeteners had faster declines in thinking and memory as they aged, even if they fell into the middle-intake group, results showed.

People who consumed moderate amounts of sugar substitutes had a brain decline 35% faster than the lowest group, equivalent to about 1.3 years of additional aging, researchers said.

Individually, aspartame, saccharin, acesulfame-k, erythritol, sorbitol and xylitol all were associated with a faster decline in overall cognition, particularly in memory, researchers said. Only the sweetener tagatose could not be linked with cognitive decline.

People younger than 60 who ate the highest amounts of sweeteners showed faster declines in language skills and overall brain power, results showed. No link was found among people 60 or older.

Researchers also found that the link to faster brain decline was stronger in people with diabetes.

“While we found links to cognitive decline for middle-aged people both with and without diabetes, people with diabetes are more likely to use artificial sweeteners as sugar substitutes,” Suemoto said.

Researchers speculated that these sweeteners might break down in the body into chemicals that are toxic to the brain or produce more inflammation.

However, they noted that the study was observational and, as such, couldn’t draw a direct cause-and-effect link between sweeteners and brain decline.

“More research is needed to confirm our findings and to investigate if other refined sugar alternatives, such as applesauce, honey, maple syrup or coconut sugar, may be effective alternatives,” Suemoto said.

More information

The Mayo Clinic has more on artificial sweeteners.

SOURCE: American Academy of Neurology, news release, Sept. 3, 2025