Popular Sugar Substitutes Linked to 62 Percent Faster Cognitive Decline, Study Warns

Researchers from the University of Sao Paulo evaluated nearly 12,800 adults over eight years, finding that high consumption of artificial sweeteners accelerates cognitive aging.

Popular Sweeteners Linked to Faster Cognitive Decline

Frequently reaching for a popular sugar substitute may come with hidden risks, as scientists warn that memory can deteriorate up to 62 percent faster. While widely considered a safe and calorie-free alternative to table sugar, a large-scale, long-term study has linked the regular consumption of popular artificial sweeteners to a drastically faster decline in cognitive abilities, including working memory and information processing speed. Individuals consuming the highest amounts of these substances experienced cognitive aging that accelerated by 62 percent, according to a report published in the medical journal Neurology, which also pointed out one surprising exception.

Researchers from the University of Sao Paulo in Brazil arrived at these concerning conclusions after examining nearly 12,800 adults with an average age of 52. At the start of the study, participants completed detailed questionnaires regarding their food and beverage intake over the previous year. Researchers then divided them into three groups based on their total sweetener consumption, taking into account seven popular low-calorie alternatives to table sugar: aspartame, saccharin, acesulfame potassium, erythritol, xylitol, sorbitol, and tagatose.

These ingredients are frequently added to highly processed products, including carbonated beverages, flavored waters, energy drinks, yogurts, and desserts advertised as low-calorie. Some of them are also sold separately for sweetening coffee or tea, as well as for use in cooked or baked dishes.

Eight Years of Observation and Mental Agility Tests

Participants underwent cognitive ability tests at the beginning, middle, and end of the study. These tests measured verbal fluency, working memory—defined as the short-term system for storing and utilizing information—word recall, and information processing speed, with participants’ health and cognitive abilities monitored for approximately eight years.

After adjusting for age, gender, high blood pressure, cardiovascular disease, and other relevant factors, researchers recorded a faster decline in cognitive abilities related to memory and thinking among individuals consuming the highest amounts of sweeteners—averaging 191 mg per day—compared to those consuming the lowest amounts, averaging 20 mg per day. For example, in the case of aspartame, the amount consumed by the highest-consumption group was close to the content found in a single can of a diet beverage.

Drastic Acceleration of Brain Aging and At-Risk Groups

Calculations showed that for individuals consuming the highest amounts of sweeteners, overall mental processes and memory performance deteriorated 62 percent, or 1.6 years, faster than for those consuming the least. Those with moderate sweetener consumption exhibited a 35 percent faster cognitive decline compared to the lowest consumption group, a difference equivalent to about 1.3 years.

The correlation between sugar substitute consumption and cognitive decline was particularly evident among individuals under the age of 60 and those with diabetes, whereas it was not observed among participants aged 60 and older. The authors noted that individuals with diabetes may consume sugar substitutes more frequently because they are advised to limit products that cause rapid spikes in blood glucose levels.

Six Sweeteners Harmful to Memory and One Exception

When researchers evaluated each sweetener individually, six of them were linked to a faster decline in overall cognitive performance, particularly memory. Tagatose was the only sweetener not associated with impaired cognitive function.

Low-calorie and calorie-free sweeteners are often perceived as a healthy alternative to sugar, but our results suggest that some of them may negatively impact brain health over time, commented study co-author Dr. Claudia Kimie Suemoto.

She also emphasized that the study was purely observational and therefore did not prove that sweeteners directly cause cognitive impairment. Instead, it allowed researchers to observe a correlation, though it remains unknown whether other factors could explain the relationship.

Study Limitations and the Need for Further Research

The study’s authors also noted that the dietary information collected was self-reported by participants. Because individuals can forget what they consumed or misjudge quantities, self-reported data may be imperfect. Furthermore, the study did not include all artificial sweeteners currently used in foods and beverages, meaning its findings cannot be applied to every sugar substitute.

Dr. Suemoto assessed that further research is needed to verify her team’s findings and determine whether other alternatives to refined sugar—such as applesauce, honey, maple syrup, or coconut sugar—can serve as effective substitutes.