Researchers at the University of São Paulo analyzed data from 12,772 Brazilian adults over eight years and found that people consuming the most low- and no-calorie sweeteners experienced 62% faster cognitive decline than those consuming the least. The study, published in Neurology, examined seven sweeteners: aspartame, saccharin, acesulfame-K, erythritol, xylitol, sorbitol and tagatose.
Participants in the highest consumption group averaged 191 mg per day of sweeteners, equivalent to roughly one can of diet soda. Those in the lowest group averaged 20 mg per day. Over the study period, the difference in cognitive decline was equivalent to approximately 1.6 additional years of brain aging. Moderate consumption was linked to 35% faster decline, or about 1.3 additional years of aging.
Participants completed cognitive assessments at the beginning, middle, and end of the study. Tests measured memory, language, verbal fluency, working memory, word recall, and processing speed.
Six sweeteners were associated with faster cognitive decline: aspartame, saccharin, acesulfame-K, erythritol, sorbitol and xylitol. Tagatose showed no association with cognitive decline in this study. The effect was stronger among adults younger than 60 and among people with diabetes.
"Our findings suggest certain sweeteners may have negative effects on brain health over time," said study author Claudia Kimie Suemoto, MD, PhD.
The study showed association, not cause-and-effect. Researchers acknowledged limitations including reliance on participants' dietary recollection and the observational design, which cannot rule out other factors explaining the relationship between sweetener intake and cognitive decline. Suemoto noted that more research is needed to confirm the findings and to investigate alternatives like applesauce, honey, and maple syrup.
The Brazilian Ministry of Health and the National Council for Scientific and Technological Development supported the research.