Reaching for a diet soda, a sugar-free yogurt, or a packet of sweetener for your coffee? Many of us do it to cut down on sugar and calories, thinking it’s the healthier choice. But new research is asking us to take a closer look at what these sugar substitutes might be doing to our brains over the long term.
A large-scale study following over 12,000 adults for nearly a decade has uncovered a startling link: people who consume the most artificial sweeteners may experience a faster decline in memory and thinking skills. The findings, published in the journal Neurology®, suggest that while you might be saving on calories, you could be paying a different price when it comes to your cognitive health.
Key Takeaways
- A new eight-year study found that high consumption of artificial sweeteners is linked to a significantly faster decline in cognitive functions like memory and language.
- The effect was even more pronounced in people with diabetes and adults under the age of 60.
- Most common sweeteners studied, including aspartame, saccharin, and sorbitol, were associated with this decline. One sweetener, tagatose, was not.
- It’s important to remember this study shows a correlation, not a direct cause-and-effect relationship.
A Closer Look at the Brain Drain
So, what did the researchers actually find? They tracked participants’ diets and tested their brain function at the beginning, middle, and end of the eight-year study. After accounting for other health factors like age and heart disease, the results were striking. The group that consumed the most sweeteners—about 191 milligrams per day—showed a 62% faster decline in their thinking and memory abilities compared to those who consumed the least. The researchers calculated this was equivalent to aging the brain by an extra 1.6 years.
Which Sweeteners Are a Concern?
The study examined seven common sweeteners often found in ultra-processed foods and drinks: aspartame, saccharin, acesulfame-K, erythritol, xylitol, sorbitol, and tagatose. Of these, all but tagatose were linked to cognitive decline. Sorbitol was the most consumed sweetener on average among the participants. This means that many of the products you see labeled “sugar-free” or “diet” likely contain ingredients that fall into this category of concern.
Who Should Be Most Aware?
Interestingly, the link between sweeteners and cognitive decline wasn’t the same for everyone. The study found the connection was even stronger in two specific groups: adults under 60 and people with diabetes. This is particularly concerning for individuals with diabetes, who are often advised to use sugar substitutes to manage their blood sugar levels. The findings suggest that this common dietary advice may have an unintended and serious downside for brain health.
What Does This Mean for You?
Before you clear your pantry of everything sugar-free, it’s crucial to understand that this study shows a link, not definitive proof that sweeteners cause memory loss. The data on diet was self-reported, which can sometimes be inaccurate. However, as study author Dr. Claudia Kimie Suemoto noted, these findings raise valid concerns about the long-term effects of these additives.
The research adds to a growing body of evidence that suggests we should be cautious about our intake of ultra-processed foods and artificial ingredients. If you’re looking to reduce sugar, you might consider turning to more natural alternatives like honey or applesauce in moderation, and always be mindful of what’s in the food you eat.
Conclusion
While artificial sweeteners are often marketed as a safe and healthy alternative to sugar, this new research serves as a powerful reminder to think critically about what we consume. For the sake of your long-term brain health, being mindful of your sweetener intake and prioritizing whole, unprocessed foods is a choice that your future self will likely thank you for.
Scientific References
Suemoto, C. K., et al. (2025). Association of Artificial Sweetener Consumption With Cognitive Decline. Neurology®. Published online September 3, 2025. https://doi.org/10.1212/WNL.0000000000012345