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 12,772 adults with an average age of 52 across Brazil for approximately eight years. Researchers examined seven sweeteners containing little or no calories: aspartame, saccharin, acesulfame K, erythritol, xylitol, sorbitol, and tagatose.
Participants completed food questionnaires and cognitive assessments at the beginning, midpoint, and end of the study. Those in the highest consumption group — averaging 191 mg of sweeteners per day — experienced a 62% faster decline in overall thinking and memory abilities compared to the lowest consumption group, who averaged 20 mg per day.
Researchers estimated this difference was comparable to approximately 1.6 additional years of cognitive aging. Participants in the middle consumption group experienced a 35% faster decline, equivalent to roughly 1.3 years of aging.
The association was particularly strong among adults under 60 and those with diabetes. Among participants younger than 60, those who consumed the most sweeteners showed faster declines in verbal fluency and overall cognitive performance. Researchers did not find the same association among participants older than 60.
Of the seven sweeteners studied, six were linked to faster declines in overall cognition, particularly memory: aspartame, saccharin, acesulfame K, erythritol, sorbitol, and xylitol. Tagatose was the only sweetener not associated with cognitive decline.
"Low- and no-calorie sweeteners are often seen as a healthy alternative to sugar, however our findings suggest certain sweeteners may have negative effects on brain health over time," said study author Dr. Claudia Kimie Suemoto of the University of São Paulo.
The researchers emphasized that the study was observational and does not prove that sweeteners directly cause cognitive decline. Other factors associated with higher sweetener consumption could help explain the pattern. They called for more research to confirm the findings and investigate whether alternatives like honey, maple syrup, or coconut sugar may be healthier options.
