Artificial sweeteners may not be as harmless as once thought. A new study published in Neurology, the journal of the American Academy of Neurology, suggests that certain sugar substitutes are linked to faster declines in memory and thinking skills, particularly in people under 60.
Researchers followed 12,772 adults in Brazil, average age 52, for about eight years. Participants reported their diets and underwent repeated cognitive tests. Those who consumed the most sweeteners, commonly found in diet soda, flavored waters, energy drinks, yogurt and low-calorie desserts, showed 62% faster overall cognitive decline than those who consumed the least. The difference was roughly equivalent to 1.6 years of additional brain aging.
The effect was strongest in middle-aged adults and in people with diabetes, who are more likely to use sugar substitutes. Specific sweeteners tied to decline included aspartame, saccharin, acesulfame-K, erythritol, xylitol and sorbitol. No link was found for tagatose.
“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 Claudia Kimie Suemoto, MD, PhD, of the University of São Paulo.
The study was observational, meaning it cannot prove that sweeteners cause memory loss. Limitations include self-reported diet data and incomplete coverage of all possible sweeteners. Still, the findings raise important questions about long-term use of sugar substitutes, especially in ultraprocessed foods.
More research is needed to confirm the link and to explore whether natural alternatives, such as fruit purées, honey or maple syrup, could provide safer options.
The research was supported by the Brazilian Ministry of Health, the Ministry of Science, Technology, and Innovation, and the National Council for Scientific and Technological Development.