Study Links Six Common Artificial Sweeteners to Faster Brain Aging

A new study conducted by researchers in Brazil found that six widely used artificial sweeteners were associated with signs of accelerated brain aging and declines in cognitive function.

The researchers reported that people with the highest intake of the sweeteners—identified as aspartame, saccharin, acesulfame potassium, erythritol, xylitol and sorbitol—showed greater declines in memory, language and thinking skills compared with those who consumed the least. On average, the group with the largest intake had brains that appeared about 1.6 years older than those with the lowest intake. The highest-consumption group was reported to ingest roughly 190 to 200 milligrams per day of the sweeteners.

The six sweeteners tested are commonly used in products marketed as "sugar-free" or "diet": sodas, low-calorie desserts, yogurt, snacks, milk-based beverages, candy and commercial packet sweeteners such as Equal, NutraSweet, Sweet'N Low, Sunett, Truvia and Xylosweet. Millions of people worldwide use these ingredients to manage weight, control blood sugar or avoid cavities.

The researchers said the association was particularly pronounced among people with diabetes, a group more likely to use low- and no-calorie sweeteners as sugar substitutes. The study also estimated that consuming the equivalent of one diet fizzy drink per day was linked to a roughly 62 percent higher risk of markers the investigators equated with brain aging, an increase researchers described as about 1.6 years of accelerated brain age.

Investigators cautioned that the mechanisms behind the observed associations are not yet established. Previous work has suggested that some sweeteners may contribute to blood clotting and inflammatory processes in the brain, but study authors said further research is needed to determine causality and to clarify biological pathways.

The study was led by researchers in Brazil; one identified co-author is Dr. Claudia Kimie Suemoto, an assistant professor in cardiovascular disease and dementia at the University of São Paulo. The authors emphasized the need for additional studies to confirm the findings and to assess whether reductions in sweetener intake would alter cognitive trajectories.

Independent experts responding to the research said the findings raise important questions about the long-term effects of low- and no-calorie sweeteners on brain health but urged caution in interpreting the results. Observational studies can show associations but cannot prove that the sweeteners caused the cognitive changes. Experts additionally noted that people who consume diet products differ in other ways from those who do not, and residual confounding can affect results.

Public health implications could be substantial because artificial sweeteners are ubiquitous in the food supply and widely recommended in some clinical settings to reduce caloric or sugar intake. The researchers and outside commentators said that, pending further confirmation, clinicians and patients should weigh potential benefits and risks when choosing sugar substitutes, particularly for people with diabetes or other conditions that affect cognitive health.

The authors called for larger, longer-term studies and experimental research to test whether reducing consumption of these common sweeteners would alter the trajectory of cognitive decline. Until more definitive evidence is available, public health guidance is likely to continue emphasizing overall dietary patterns, control of vascular risk factors and other established strategies to protect brain health.