SerpApi.Org
A growing body of research is challenging the long-held belief that artificial sweeteners are a harmless substitute for sugar. A large eight-year study involving more than 12,700 adults found that people consuming roughly the amount of artificial sweetener found in one can of diet soda per day experienced cognitive decline 62% faster than those with minimal intake. Researchers estimated that difference to be equivalent to approximately 1.6 additional years of brain aging.
New Studies Link Artificial Sweeteners to Brain Health and Gut Microbiome Changes
The Brazilian study, published in Neurology, followed adults with an average age of 52 and evaluated memory, verbal fluency, processing speed, and working memory over eight years. Participants consuming the highest amounts of artificial sweeteners consistently performed worse over time than those consuming the least, even after researchers adjusted for factors such as age, cardiovascular disease, blood pressure, and other health conditions. Importantly, this was an observational study, meaning it identified an association rather than proving that artificial sweeteners directly caused cognitive decline.
Researchers also examined individual sweeteners. Aspartame, saccharin, acesulfame K, erythritol, sorbitol, and xylitol were each associated with faster cognitive decline, while tagatose did not show the same relationship. These ingredients are commonly found in diet sodas, sugar-free gum, tabletop sweeteners, and many "low-carb" or diabetic-friendly products consumed daily by millions of people.
A second study from the University of Cambridge added another layer of concern by investigating how artificial sweeteners interact with the gut microbiome. Scientists found that many sweeteners altered the growth of beneficial gut bacteria, and some of those effects became even stronger when combined with commonly prescribed medications, including certain antidepressants. Since gut bacteria influence inflammation, metabolism, and communication with the brain through the gut-brain axis, researchers believe this pathway deserves further investigation.
The Brazilian study also identified interesting differences among participants. Adults younger than 60 and people living with diabetes showed the strongest associations between artificial sweetener intake and faster cognitive decline. Researchers caution that this finding requires additional study, especially because people with diabetes are often encouraged to replace sugar with artificial sweeteners as part of their dietary management.
While these findings are significant, experts stress that they should not be interpreted as proof that diet sodas or artificial sweeteners directly cause dementia or cognitive impairment. Instead, the research highlights a potential long-term relationship that deserves careful investigation through future clinical trials. For individuals seeking to support brain health, many nutrition professionals continue recommending moderation, emphasizing whole foods, water as the primary beverage, and limiting highly processed foods—whether they contain added sugar or artificial sweeteners.
