6 Artificial sweeteners are often marketed as a healthier alternative to sugar, especially for those looking to lose weight or manage conditions like diabetes. But a new study suggests that consuming high amounts of certain sugar substitutes could speed up brain aging and increase the risk of cognitive decline.
The Study Findings
Published on September 3 in Neurology, the study analyzed data from more than 12,700 Brazilian adults with an average age of 52. Researchers tracked the consumption of seven low- or no-calorie sweeteners commonly found in diet sodas, low-calorie desserts, yogurt, and other processed foods.
The sweeteners included:
- Aspartame
- Saccharin
- Xylitol
- Erythritol
- Sorbitol
- Acesulfame K
- Tagatose
The results were striking. Participants who consumed the highest amounts of six of these sweeteners (all except tagatose) experienced significantly faster declines in memory, thinking speed, and verbal fluency compared to those who consumed little or none.
In fact, heavy consumers of artificial sweeteners showed signs of 1.6 years of additional brain aging.
How Sweeteners Affect the Brain
Study author Dr. Claudia Kimie Suemoto, a geriatric specialist at the University of São Paulo, explained that while drinking one can of diet soda won’t instantly harm your memory, frequent consumption could lead to accelerated brain aging over time.
Experts believe the effects may be linked to gut microbiome disruptions and inflammation, both of which can negatively impact brain function. When gut bacteria become imbalanced, the brain’s immune cells—called microglia—may shift into an inflammatory state, which raises the risk of Alzheimer’s disease, Parkinson’s, and other neurodegenerative conditions.
Nutrition experts also highlighted that the study controlled for overall diet quality, meaning the sweeteners themselves—not just poor diets—were associated with worse brain health outcomes.
Key Numbers From the Research
- Moderate consumers (about 66 mg daily) had a 35% faster decline in memory and thinking and a 110% faster decline in verbal fluency.
- High consumers (around 191 mg daily, roughly one can of diet soda) showed a 62% faster decline in memory and thinking and a 173% faster decline in verbal fluency.
- The effect was especially pronounced in people under 60 and even stronger for those with diabetes.
Why Diabetes Patients May Face Higher Risks
People with diabetes often use artificial sweeteners to reduce sugar intake. However, the combination of diabetes—which already affects metabolism and gut health—and high consumption of artificial sweeteners may create a “double burden” on the brain.
“Diabetes already primes the body for inflammation,” explained neurologist Dr. David Perlmutter. “Adding artificial sweeteners may intensify that process, worsening the risk of cognitive decline.”
Should You Cut Out Artificial Sweeteners?
The findings don’t prove that artificial sweeteners directly cause dementia or memory loss, but they raise serious concerns. Experts recommend limiting processed foods and aiming for a diet rich in whole, fiber-filled foods that support gut and brain health.
That doesn’t mean replacing artificial sweeteners with sugar is the answer—since high sugar intake is also linked to dementia and other chronic conditions. Instead, the best strategy may be to reduce overall sweetness in your diet.
“When possible, retrain your taste buds to enjoy less sweet foods,” advised Dr. Perlmutter. “If you need an alternative, opt for less processed options like stevia or tagatose.”
The Takeaway
This large-scale study is one of the clearest signals yet that six widely used artificial sweeteners—aspartame, saccharin, xylitol, erythritol, sorbitol, and acesulfame K—may contribute to faster cognitive decline, particularly in younger adults and those with diabetes.
While more research is needed to fully understand the connection, one thing is clear: both sugar and artificial sweeteners carry risks. Building a diet centered on whole, nutrient-rich foods may be the best way to protect long-term brain health.
