Study Links High Sweetener Intake to Faster Cognitive Decline

What the Study Found on Sweeteners and Cognitive Decline

Adults with the highest intake of low-calorie sweeteners experienced a 62 percent faster decline in thinking and memory skills compared to adults with the lowest intake. A study published in Neurology, the medical journal of the American Academy of Neurology, tracked 12,772 adults across Brazil over an eight-year period. The average participant age was 52 years when the study began.

Researchers evaluated cognitive performance at the start, midpoint, and conclusion of the study. The assessments measured working memory, verbal fluency, word recall, and mental processing speed.

Daily Intake Levels and Sweeteners Evaluated in the Cohort

Participants in the highest consumption bracket consumed an average of 191 milligrams of low- and no-calorie sweeteners per day. Individuals in the lowest consumption group averaged 20 milligrams per day. For comparison, 191 milligrams of aspartame is roughly the quantity found in one can of diet soda.

The investigation tracked seven specific sugar substitutes: aspartame, saccharin, acesulfame-K, erythritol, xylitol, sorbitol, and tagatose. Among these ingredients, sorbitol accounted for the highest average daily intake at 64 milligrams per day.

Estimated Brain Aging and the Effect on Adults with Diabetes

The cognitive decline observed in the highest sweetener group corresponded to approximately 1.6 additional years of brain aging over the eight-year study. Participants in the middle consumption tier also showed measurable changes, experiencing a 35 percent faster cognitive decline, which equaled approximately 1.3 additional years of aging. These outcomes remained consistent after researchers adjusted for age, sex, high blood pressure, and cardiovascular disease.

The association between sweetener consumption and accelerated cognitive decline appeared particularly pronounced in individuals with diabetes. These ingredients appear frequently in ultra-processed products marketed for blood sugar control, such as diet sodas, flavored waters, energy drinks, yogurts, and low-calorie desserts.

Observational Design and Key Limitations of the Findings

The findings demonstrate a statistical association and do not establish a cause-and-effect relationship between sweetener consumption and brain decline. Researchers relied on baseline dietary questionnaires covering the previous year to estimate sweetener intake. Because the research was observational, the authors cannot conclude that sugar substitutes directly harm brain tissue or cause memory loss.

Lead author Claudia Kimie Suemoto of the University of São Paulo noted that while sugar substitutes are often used as alternatives to table sugar, long-term cognitive outcomes require further investigation. Individuals managing blood sugar should discuss dietary modifications with their primary clinician before altering established routines.