A new study has found that heavy consumption of artificial sweeteners, including those found in diet soda, may accelerate memory loss and cognitive decline.
Published in the journal Neurology, the research conducted in Brazil revealed that participants who consumed the highest levels of artificial sweeteners experienced “significantly faster declines” in memory and thinking skills.
Tracking 12,772 adults with an average age of 52 over eight years, researchers discovered that those in the highest-consuming group showed the equivalent of 1.6 years of additional brain aging and a 62% faster decline compared with those who consumed the least.
The groups most at risk were adults under 60 and people with diabetes. Surprisingly, older adults above 60 did not appear to be affected.
Researchers stressed that exposure to sweeteners during midlife may be particularly harmful, as this is a critical period for long-term brain health.
The study examined seven commonly used sweeteners: aspartame, saccharin, acesulfame-K, erythritol, xylitol, sorbitol and tagatose.
All but tagatose were linked to faster cognitive decline, particularly in memory. These additives are often found in diet sodas, energy drinks, flavored water, yogurt, and other low-calorie desserts.
“People often believe artificial sweeteners are a safer alternative to sugar, but our results suggest they may not be harmless,” said Dr. Claudia Kimie Suemoto of the University of São Paulo, the study’s lead author.
She urged the public to cut back not only on added sugar but also on artificial sweeteners, and to focus instead on a diet rich in whole, natural foods.
Dr. Brintha Vasagar, a U.S.-based family physician not involved in the study, echoed the caution, according to Fox News.
While some patients may benefit from avoiding sugars in their diet, she said most people are safer consuming natural sugars in moderation.
She also warned that artificial sweeteners may alter taste perception, driving people to seek more sugar for the same level of satisfaction.
The Calorie Control Council, an industry group, disputed the findings, stressing that low- and no-calorie sweeteners are among the most heavily studied food additives and are consistently deemed safe by regulators such as the U.S. Food and Drug Administration and the European Food Safety Authority.
The group said the study relied on self-reported data and showed only correlation, not causation.
While more research is needed, the study’s authors say the safest step is to reduce artificial sweetener use as much as possible, ideally avoiding them altogether.
They recommend natural alternatives in moderation, such as fruit, honey, or maple syrup, alongside a balanced diet to support long-term brain health.
