Many people choose foods and drinks with artificial sweeteners because they contain little or no sugar. These products are often promoted as better choices for weight control or diabetes.
However, a new study suggests that regularly consuming large amounts of several popular sugar substitutes may be linked to faster declines in memory and thinking skills over time.
The research was led by Dr. Claudia Kimie Suemoto from the University of São Paulo in Brazil and published in Neurology, the medical journal of the American Academy of Neurology.
The findings add to growing interest in how diet may affect brain health as people age.
Artificial sweeteners have become common in modern diets. They are found in diet soft drinks, flavored water, sugar-free yogurt, chewing gum, desserts, protein products, and many other ultra-processed foods. Some people also add them directly to coffee, tea, or home cooking.
The researchers wanted to find out whether long-term use of these sweeteners was linked to changes in brain function. They studied 12,772 adults living in Brazil whose average age was 52 years. None of the participants were followed for only a short period because the study continued for about eight years, allowing the researchers to observe gradual changes.
At the beginning of the study, participants completed detailed questionnaires about everything they had eaten and drunk during the previous year. Using these records, the scientists estimated how much of seven low- or no-calorie sweeteners each person consumed. They examined aspartame, saccharin, acesulfame K, erythritol, xylitol, sorbitol, and tagatose.
The volunteers also completed memory and thinking tests at the start of the study, halfway through, and again at the end. These tests measured memory, word recall, language skills, working memory, and the speed at which the brain processed information. Together, these tests gave researchers a broad picture of overall brain function.
When the results were analyzed, people with the highest total sweetener intake showed a much faster decline in thinking and memory than those with the lowest intake. The difference was similar to about 1.6 extra years of brain aging. Even people with moderate intake experienced a faster decline than those who consumed the least.
The connection appeared strongest in adults younger than 60 years. It was also stronger among people with diabetes, who often use sugar substitutes instead of sugar to help control blood glucose levels.
When the researchers looked at each sweetener separately, six of the seven were linked to faster declines in memory and thinking. Tagatose was the only sweetener that did not show this association.
The study does not prove that artificial sweeteners damage the brain. It was an observational study, meaning it found a relationship but could not show cause and effect. It is possible that other lifestyle habits, health conditions, or dietary patterns contributed to the findings, even though the researchers adjusted for many important factors.
The study also has other limitations. People’s diets were based on their own memories, which are not always perfectly accurate. In addition, only seven sweeteners were studied, so the results cannot be applied to every sugar substitute available today.
For people who regularly consume diet foods or drinks, these findings are worth paying attention to but should not cause panic. Experts generally recommend focusing on an overall healthy eating pattern that includes plenty of fruits, vegetables, whole grains, nuts, and minimally processed foods rather than relying heavily on artificially sweetened products.
Overall, this large long-term study suggests that consuming high amounts of several popular sugar substitutes may be linked to faster cognitive decline, especially in middle-aged adults and people with diabetes.
However, stronger evidence from clinical trials is still needed before scientists can conclude that these sweeteners directly affect brain health. The study raises important questions and supports further research into safer ways to reduce sugar intake while protecting long-term brain function.
If you care about brain health, please read studies about Vitamin B9 deficiency linked to higher dementia risk, and flavonoid-rich foods could help prevent dementia.
For more health information, please see recent studies that cranberries could help boost memory, and how alcohol, coffee and tea intake influence cognitive decline.
Source: University of São Paulo.
