Research indicates that high consumption of popular sugar substitutes may lead to faster cognitive aging, particularly in younger adults and those with diabetes.
New Delhi, India Jul 18, 2026 ALN: Several widely used sugar substitutes may be associated with faster declines in memory and thinking skills over time, according to research published in Neurology, the medical journal of the American Academy of Neurology.
The study followed nearly 13,000 adults and examined seven sweeteners that contain little or no calories. People who consumed the largest total amounts showed a more rapid decline in cognitive abilities than those who consumed the smallest amounts. The association was especially strong among people with diabetes.
The results do not show that sweeteners directly cause cognitive decline. They reveal an association, meaning other factors could help explain the pattern.
Researchers studied aspartame, saccharin, acesulfame K, erythritol, xylitol, sorbitol, and tagatose.
These ingredients are frequently added to ultra-processed products, including flavored water, soft drinks, energy drinks, yogurt, and desserts marketed as low in calories. Several are also sold separately for use in coffee, tea, cooking, or baking.
"Low- and no-calorie sweeteners are often seen as a viable alternative to sugar; however, our findings suggest certain sweeteners may have negative effects on the brain over time," said study author Claudia Kimie Suemoto, MD, PhD, of the University of São Paulo in Brazil.
The research included 12,772 adults living across Brazil. Participants were 52 years old on average and were monitored for approximately eight years.
At the beginning of the study, participants completed detailed food questionnaires describing what they had eaten and drunk during the previous year. Researchers then placed them into three groups according to their total sweetener intake.
People in the lowest consumption group averaged 20 milligrams per day (mg/day), while those in the highest group averaged 191 mg/day. In the case of aspartame, the amount consumed by the highest group was roughly equal to the aspartame in one can of diet soda.
Sorbitol was consumed in the largest quantity of any individual sweetener, with an average daily intake of 64 mg/day.
Participants completed cognitive assessments at the beginning, midpoint, and end of the study. The tests measured several aspects of brain function, including verbal fluency, working memory, word recall, and processing speed.
Verbal fluency refers to the ability to quickly retrieve and produce words. Working memory is the brain's short-term system for holding and using information, while processing speed reflects how quickly a person can understand and respond to information.
After accounting for age, sex, high blood pressure, cardiovascular disease, and other relevant factors, the researchers found a clear difference between the intake groups.
People who consumed the greatest amounts of sweeteners experienced a 62% faster decline in overall thinking and memory abilities than those who consumed the least. Researchers estimated that this difference was comparable to about 1.6 additional years of aging.
Participants in the middle consumption group experienced a decline that was 35% faster than the decline observed in the lowest group. That difference was comparable to approximately 1.3 years of aging.
Age appeared to influence the results. Among participants younger than 60, those who consumed the most sweeteners experienced faster declines in verbal fluency and overall cognitive performance than those who consumed the least.
Researchers did not find the same association among participants older than 60.
The connection between sweetener intake and faster cognitive decline was also stronger among people with diabetes than among those without the condition. People with diabetes may use sugar substitutes more frequently because they are often advised to limit products that rapidly raise blood sugar.
When the researchers examined the sweeteners separately, six were associated with faster declines in overall cognition, particularly memory.
Those sweeteners were aspartame, saccharin, acesulfame K, erythritol, sorbitol, and xylitol.
Tagatose was the only sweetener in the study that was not linked to cognitive decline.
"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. "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."
The study did not include every artificial sweetener currently used in food and beverages, so the findings cannot be applied to all sugar substitutes.
The dietary information was also provided by the participants themselves. Because people may forget foods or misjudge how much they consumed, self-reported diet data can be imperfect.
Most importantly, the study was observational. It identified a relationship between higher sweetener consumption and faster cognitive decline, but it could not establish that the sweeteners caused those changes.
The research was supported by the Brazilian Ministry of , the Ministry of Science, Technology, and Innovation, and the National Council for Scientific and Technological Development.
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