Emerging research suggests that some widely used sugar substitutes may be linked to faster cognitive aging, with higher consumption associated with a steeper decline in memory and thinking abilities compared with lower intake.
An extensive eight-year study following more than 12,000 adults examined how the use of artificial sweeteners relates to long-term brain health. The researchers found that participants who consumed the highest amounts of sugar substitutes, roughly the equivalent of one diet soda per day showed a rate of cognitive decline about 62% faster than those who consumed little or none. On average, their drop in cognitive performance was comparable to about 1.6 additional years of biological brain aging.
The investigation, published in the journal Neurology, assessed participants through repeated tests measuring memory, word recall, and processing speed. Individuals with the greatest intake of sweeteners experienced noticeably larger declines in these cognitive measures over time.
The association appeared especially pronounced among adults younger than 60 and people with diabetes, groups that often choose artificial sweeteners
Many of the sweeteners studied are commonly found in diet sodas, energy drinks, flavored yogurts, and other ultra-processed foods. The researchers observed that higher intake was linked to reduced verbal fluency and overall cognitive performance during the study period.
Importantly, the findings show an association rather than proof of cause and effect. Nevertheless, the results raise questions about the long-term neurological effects of frequently consuming products marketed as “diet” or “sugar-free.”
Study:
Gonçalves, N. G., Martinez-Steele, E., Lotufo, P. A., Bensenor, I., Goulart, A. C., Barreto, S. M., Giatti, L., Faria, C. P., Molina, M. C. B., Caramelli, P., Marchioni, D. M., & Suemoto, C. K. (2025). Association Between Consumption of Low- and No-Calorie Artificial Sweeteners and Cognitive Decline: An 8-Year Prospective Study. Neurology.