A large Brazilian study suggests high intake of certain sugar substitutes may speed up memory and thinking decline
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People who consumed the most artificial sweeteners experienced faster declines in memory and thinking skills.
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The effect was strongest in adults under 60 and in those with diabetes.
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The study found a link, but it does not prove that sweeteners directly cause cognitive decline.
Many of us reach for diet sodas, flavored waters, or low-calorie desserts believing theyre a healthier choice than sugary options.
However, a new study recently published in Neurology, the medical journal of the American Academy of Neurology, suggests some sugar substitutes might come with hidden risks particularly for brain health.
Researchers in Brazil followed more than 12,700 adults for nearly a decade to see how consumption of low- and no-calorie sweeteners might affect memory, language, and overall thinking abilities. They discovered that people who consumed the most sweeteners experienced faster declines in these skills, raising questions about the long-term effects of artificial sugar alternatives.
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, study author Claudia Kimie Suemoto, M.D., Ph.D., said in a news release.
The study
The study included adults with an average age of 52, who were tracked for about eight years. At the beginning, participants filled out detailed food and drink questionnaires, reporting what they consumed over the prior year.
Researchers looked specifically at seven common artificial sweeteners: aspartame, saccharin, acesulfame-K, erythritol, xylitol, sorbitol, and tagatose. These sweeteners are often found in diet drinks, energy drinks, yogurt, and low-calorie desserts.
Based on intake, participants were divided into three groups. The lowest group consumed around 20 milligrams of sweeteners per day, while the highest consumed about 191 milligrams daily the equivalent of roughly one can of diet soda for aspartame.
To measure changes over time, participants completed cognitive tests at the start, middle, and end of the study. These tests assessed memory, word recall, processing speed, and verbal fluency. Researchers then adjusted for other health factors such as age, sex, high blood pressure, and cardiovascular disease.
The findings
The researchers found that people who consumed the highest amounts of artificial sweeteners showed a decline in overall thinking and memory that was 62% faster than those who consumed the least. This was found to beequivalent to about 1.6 years of additional brain aging. Those in the middle group also saw declines, though less steep.
The link was most noticeable in adults under 60 and in those with diabetes, who are more likely to rely on sugar substitutes. Interestingly, one sweetener tagatose was not associated with cognitive decline.
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 said. More research is needed to confirm our findings and to investigate if other refined sugar alternatives, such as applesauce, honey, maple syrup or coconut sugar, may be effective alternatives.
Posted: 2025-09-08 22:02:08