New research published in the journal Neurology by the American Academy of Neurology suggests that certain popular sugar substitutes may have unintended negative effects on long-term brain health. The study analyzed data from 12,772 adults in Brazil over an eight-year period, finding that individuals with the highest intake of low- and no-calorie sweeteners experienced significantly faster declines in cognitive abilities compared to those with the lowest consumption.
Researchers examined seven specific sweeteners frequently found in ultra-processed foods such as diet sodas, flavored waters, energy drinks, yogurt, and low-calorie desserts: aspartame, saccharin, acesulfame-K, erythritol, xylitol, sorbitol, and tagatose. The analysis revealed that six of these substances—aspartame, saccharin, acesulfame-K, erythritol, sorbitol, and xylitol—were linked to faster cognitive decline. Tagatose was the only sweetener among those studied not associated with this effect, though researchers caution this does not confirm it is protective or safer.
Participants in the highest consumption group averaged 191 milligrams of sweeteners per day, roughly equivalent to one can of diet soda, while the lowest group averaged 20 milligrams. After adjusting for factors like age, sex, high blood pressure, and cardiovascular disease, the study found that the high-consumption group experienced a 62% faster decline in overall thinking and memory skills. This difference translates to approximately 1.6 additional years of cognitive aging over the study period. Even moderate consumption was associated with a 35% faster decline, equivalent to about 1.3 extra years of aging.
The association between sweetener intake and cognitive decline was particularly pronounced among adults under the age of 60 and individuals with diabetes. While no similar link was found in participants older than 60, the connection remained strong for those managing diabetes, a group that frequently relies on sugar substitutes to control blood sugar levels. The study measured changes in verbal fluency, working memory, word recall, and processing speed at three points during the eight-year follow-up.
Study author Claudia Kimie Suemoto, MD, PhD, from the University of São Paulo, noted that while these sweeteners are often viewed as healthy alternatives to sugar, the findings suggest they may negatively impact brain health over time. However, the researchers emphasized that the study demonstrates an association rather than a proven cause-and-effect relationship. It cannot be concluded from this data that consuming these sweeteners directly damages the brain or causes memory loss.
The research acknowledges several limitations, including the reliance on participants' self-reported dietary habits and the fact that not all available artificial sweeteners were covered in the analysis. The observational design also means other unmeasured factors could influence the results. Further studies are needed to determine if the sweeteners themselves contribute to brain function changes and to explore whether other alternatives like honey, maple syrup, or applesauce might offer different long-term outcomes.
Sources: ScienceDaily.