Sugar Substitutes Linked to Accelerated Brain Aging in 8-Year Study of 12,000 People

Regular consumption of low-calorie sweeteners correlates with faster decline in memory and cognitive abilities. According to a study published in the medical journal Neurology, cognitive functions in people with the highest sweetener intake declined 62% faster, equivalent to roughly 1.6 years of premature brain aging.

The Equivalent of One Diet Soda Can a Day

The work relies on data from the Brazilian cohort project ELSA-Brasil, which tracked 12,772 adult participants over eight years (with an average initial age of 52).

According to medical publication Neurology Today, the high-intake group consumed an average of 191 mg of sweeteners per day, compared to just 20 mg in the low-intake group. In terms of aspartame, that daily amount is roughly equal to what is found in a single 0.33-liter can of diet soda.

However, the authors emphasize that this reflects total sweetener intake across the entire diet, including low-fat yogurts, low-calorie desserts, sauces, and processed foods.

Which Substances Came Under Scrutiny

During the study, researchers separately tested the effects of seven popular sweeteners:

• Artificial sweeteners: aspartame, saccharin, acesulfame potassium (acesulfame-K);
• Sugar alcohols (polyols): erythritol, xylitol, sorbitol;
• Rare sugars: tagatose.

The first six compounds showed a strong statistical link to declines in short-term memory and verbal fluency. Tagatose was the only substance that showed no negative correlation with cognitive tests.

Age Factors and People With Diabetes

The steepest drops in cognitive test scores were recorded in participants under age 60 and in patients diagnosed with diabetes. In the over-60 group, researchers found no statistically significant impact of sweeteners on the rate of cognitive change.

Correlation, Not Proven Causation

The study’s authors and science commentators on EurekAlert! urge caution against jumping to definitive conclusions. The study is observational rather than a clinical trial:

• dietary intake was evaluated through participant questionnaires and self-reports;
• unaccounted lifestyle and metabolic factors could have influenced the findings;
• the data show a statistical correlation but do not directly prove that sugar substitutes damage neurons.

Medical experts also advise against switching back to regular sugar, noting that excess sucrose carries well-established risks of obesity, diabetes, and cardiovascular disease.

Scientific Review and Data Recalculation

The study went through an extensive verification process: following its initial release in the fall of 2025, the authors identified technical inaccuracies in their calculations. In the summer of 2026, the research team conducted a full re-audit of the raw datasets from scratch. In the August issue of Neurology, the editors confirmed that after correcting the formulas, the paper’s key findings regarding cognitive health risks held up entirely.