Metal spoon scooping white powdered artificial sweetener
Millions of people swap sugar for zero-calorie substitutes to protect their health and manage their weight. But a massive new observational study suggests this daily habit might accelerate cognitive decline over time.
Research published by the American Academy of Neurology in the medical journal Neurology on July 18, 2026, links high artificial sweetener consumption to faster aging of the brain.
A metal spoon scooping white powdered artificial sweetener.
The Eight-Year Brain Check
The study tracked 12,772 adults across Brazil over an eight-year period. Participants, whose average age was 52, underwent regular testing for working memory, word recall, processing speed, and verbal fluency.
Researchers discovered a stark contrast between those who consumed the most and least amounts of sugar substitutes. The highest-intake group experienced a 62% faster decline in overall thinking and memory skills.
The research team noted this drop is equivalent to roughly 1.6 additional years of brain aging. Even the moderate consumption group saw a 35% faster cognitive decline, mirroring about 1.3 extra years of aging.
The Diet Soda Benchmark
What constitutes a “high” intake? The highest consumption group averaged 191 milligrams of sweeteners per day. For context, that amount is roughly equivalent to the aspartame found in a single can of diet soda.
In contrast, the lowest consumption group averaged just 20 milligrams daily.
Six Chemicals Linked to Memory Drops
Researchers isolated seven specific zero-calorie sweeteners commonly found in diet drinks, low-calorie yogurts, and baked goods. Six of them showed a direct link to faster memory decline: aspartame, saccharin, acesulfame K, erythritol, sorbitol, and xylitol.
Sorbitol topped the specific consumption charts, averaging 64 milligrams daily among users. Tagatose was the single sweetener tested that did not correlate with cognitive drop-offs.
“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 Dr. Claudia Kimie Suemoto of the University of São Paulo in Brazil.
High Risk for Diabetics and Under-60s
The cognitive impact was not uniform across all demographics. The association between sweeteners and brain decline was notably stronger in adults under the age of 60. The link vanished in participants older than 60.
Furthermore, people with diabetes showed a significantly higher vulnerability to these memory changes. Diabetics frequently rely on artificial sweeteners to avoid blood sugar spikes, inadvertently increasing their exposure.
“While we found links to cognitive decline for middle-aged people both with and without diabetes, people with diabetes are more likely to use artificial sweeteners as sugar substitutes,” Dr. Suemoto noted.
Correlation, Not Causation
Scientists caution that the findings establish an observational link, not a definitive cause. Diet data was self-reported, meaning exact consumption volumes may be imperfect due to simple forgetfulness.
The study—supported by the Brazilian Ministry of Health and the National Council for Scientific and Technological Development—did not include every sweetener on the market. Researchers stressed that further clinical trials are necessary to prove if artificial sweeteners directly cause damage to brain function.
