Over eight years, adults who consumed more low‑ and no‑calorie sweeteners—especially several artificial types and sugar alcohols—saw steeper drops in memory and thinking. One natural sweetener, tagatose, showed no link to harm.  

What’s new

A prospective study in Neurology followed 12,772 middle‑aged and older adults from the ELSA‑Brasil cohort for a median of eight years. Researchers tracked intake of seven common low‑/no‑calorie sweeteners (aspartame, saccharin, acesulfame‑K, erythritol, xylitol, sorbitol, and tagatose) and measured cognition three times (memory, verbal fluency and a processing‑speed task). Higher total sweetener intake was linked to faster decline in verbal fluency and global cognition after accounting for age, education, health conditions, lifestyle and overall diet.

How big was the effect?

Compared with the lowest‑intake group, people in the middle and highest thirds of total sweetener consumption had 110% and 173% faster declines in verbal fluency, and 35% and 62% faster declines in overall cognition—roughly equivalent to 1.3 to 1.6 extra years of “cognitive aging.” Daily users also declined faster than non‑ or occasional users.  

Which sweeteners stood out?

Signals differed by health status:

• Without diabetes: higher intakes of erythritol and xylitol were associated with faster decline in memory and global cognition; sorbitol was linked to faster decline across memory, verbal fluency and global scores.  
• With diabetes: higher aspartame and acesulfame‑K intake tracked with faster decline in memory, verbal fluency and global cognition; saccharin and xylitol were also tied to faster memory and global decline.  
• Tagatose, a naturally occurring sweetener, was not associated with cognitive decline overall, and in adults under 60 it was linked to slower decline in memory and global cognition.

How the study worked

Sweetener intake was estimated once at baseline using a validated food‑frequency questionnaire and grouped into low, medium and high tertiles (≈0.02–37.2 mg; 37.3–102.3 mg; 102.4–856.5 mg per day). Cognitive testing occurred every four years. Analyses used mixed‑effects models adjusted for demographics, education, income, physical activity, BMI, hypertension, diabetes, cardiovascular disease, depressive symptoms, alcohol, smoking, total calories and a healthy‑diet score; inverse‑probability weighting helped account for drop‑outs. The chart on page 7 shows progressively steeper downward slopes in global cognition with higher tertiles of total sweetener intake.

Why it matters

Global use of low‑/no‑calorie sweeteners has risen alongside ultra‑processed “diet” foods and drinks. Even within current acceptable daily intakes, prior studies have linked some sweeteners with metabolic and cardiovascular risks; this new work adds brain health to the conversation.  

Important caveats

This is observational research—it cannot prove that sweeteners cause cognitive decline. Diet was measured once (people may change habits), intake was self‑reported, and unmeasured behaviors could still influence results. Brain imaging was not available to explore biological mechanisms.  

Bottom line for readers

The findings suggest that regularly relying on some artificial sweeteners and certain sugar alcohols may be linked to faster cognitive aging, while tagatose did not show harm in this study. Emphasizing water and unsweetened beverages, and choosing minimally processed foods, remain sensible strategies while research continues. If you use sweeteners for medical reasons (e.g., diabetes), discuss options with your clinician.  

Study details at a glance

• Population: 12,772 Brazilian adults (35–74 at baseline).  
• Exposure: Seven sweeteners measured in mg/day; tertiles used for analysis.  
• Outcomes: Memory, verbal fluency, Trail‑Making Test; global cognition composite.  
• Key figure: Figure 2 (page 7) shows steeper cognitive decline across higher intake tertiles.  

Source: Gomes Gonçalves N. et al., “Low‑ and No‑Calorie Sweeteners and Cognitive Decline,” Neurology*, 2025.* 

Gonçalves, N. G., Martinez-Steele, E., Lotufo, P. A., Bensenor, I., Goulart, A. C., Barreto, S. M., Giatti, L., de Faria, C. P., Molina, M. D. 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, 105(7), e214023. https://doi.org/10.1212/WNL.0000000000214023

Editor’s note: This article is for information only and is not a substitute for professional medical advice.