By Peter Omopo
A large-scale Brazilian study has found a significant association between high consumption of artificial sweeteners and faster decline in memory and thinking skills — raising questions about the long-term impact of “diet” sugar substitutes on brain health.
Key Findings
- The research followed 12,772 adults, averaging 52 years old at baseline, for eight years.
- Participants were grouped by their reported intake of seven low- or no-calorie sweeteners (LNSCs) including aspartame, saccharin, acesulfame K, erythritol, sorbitol, xylitol and tagatose.
- Those in the highest consumption group (≈ 191 mg/day, roughly equivalent to one can of diet soda) experienced a 62% faster cognitive decline compared to the lowest intake group — equivalent to about 1.6 extra years of brain ageing.
- The effect was strongest in people under age 60 and in participants with diabetes. No significant association was found in participants over 60.
- While the study is observational and does not prove causation, the authors suggest the findings “raise the possibility of long-term harm” from high intake of certain artificial sweeteners.
What It Means
Experts say this research challenges the assumption that artificial sweeteners are entirely benign alternatives to sugar. Dr. Claudia Kimie Suemoto of the University of São Paulo, lead author of the study, said:
“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.”
Potential mechanisms include changes in the gut microbiome, inflammation, and metabolic effects that might ultimately affect brain health.
Expert & Regulatory Perspectives
- The International Sweeteners Association notes that artificial sweeteners such as those in the study are approved by global health authorities and have been considered safe within established intake levels.
- Observers emphasise caution: given the reliance on self-reported diet data and the observational design, more research — including studies that use neuroimaging — is needed to clarify whether the association is causal.
What to Do
While the science continues to evolve, nutrition and brain-health experts suggest:
- Moderation in consumption of artificial sweeteners, especially among younger adults and those with diabetes.
- Preference for whole-food, minimally processed diets rather than relying heavily on ultra-processed “diet” products.
- Keeping an overall healthy lifestyle — good sleep, regular physical activity, cognitively stimulating activities — which together support brain health.
Conclusion
This study adds to a growing body of evidence suggesting that the long-term cognitive effects of artificial sweetener consumption may not be fully understood. While the findings do not warrant immediate alarm or avoidance, they do signal that the impact of such sweeteners on brain function deserves deeper investigation — and that consumers may wish to choose them with awareness rather than assumption of harmlessness.
