New research shows that some popular sugar substitutes might be linked to quicker loss of memory and thinking skills. The study was published in the medical journal Neurology.
Researchers followed almost 13,000 adults for about eight years. They looked at seven low‑calorie sweeteners: aspartame, saccharin, acesulfame K, erythritol, xylitol, sorbitol and tagatose. These sweeteners are common in diet sodas, flavored water, energy drinks, low‑calorie yogurts and sugar‑free desserts.
How the Study Was Done
The participants lived all over Brazil and were on average 52 years old at the start. Each person filled out a detailed food questionnaire that asked about everything they ate and drank in the past year.
Based on the answers, scientists put participants into three groups: low, medium and high sweetener intake. The low group ate about 20 mg per day, the medium group about 100 mg, and the high group about 191 mg. For reference, that much aspartame is roughly what you find in one can of diet soda.
Researchers measured brain performance three times using tests for verbal fluency (how fast you can think of words), working memory (short‑term thinking), word recall and processing speed.
What They Found
After adjusting for age, sex, blood pressure and heart disease, the high‑intake group showed a 62 % faster drop in overall thinking and memory compared with the low‑intake group. That difference is similar to adding about 1.6 years of normal aging.
The medium‑intake group also declined faster—about 35 % more than the low group, which is like gaining roughly 1.3 extra years.
The link was strongest in participants younger than 60. In that age range, high sweetener users lost verbal fluency and overall cognition more quickly. The pattern was not seen in people older than 60.
People with diabetes showed an even stronger connection. Since many with diabetes rely on sugar substitutes to control blood sugar, they may be consuming more of these products.
Which Sweeteners Were Most Problematic?
When examined one by one, six sweeteners— aspartame, saccharin, acesulfame K, erythritol, sorbitol and xylitol—were tied to faster memory decline. Tagatose did not show a clear link.
Things to Keep in Mind
- The study did not include every artificial sweetener on the market.
- Diet information came from participants themselves, so it may contain mistakes.
- Because the research is observational, it can only show a relationship, not prove that sweeteners cause brain changes.
More studies are needed to confirm these findings and to explore whether natural alternatives such as applesauce, honey, maple syrup or coconut sugar are safer choices.
Key Takeaways
- 13,000 adults, average age 52, were tracked for eight years.
- Seven common low‑calorie sweeteners were studied.
- Higher total sweetener intake was linked to faster loss of memory and thinking.
- The effect was similar to adding about 1.6 years of age.
- The association appeared mainly in people under 60 and in those with diabetes.
- These results show a link, not a cause‑and‑effect relationship.
This research was supported by Brazil's Ministry of Health, the Ministry of Science, Technology and Innovation, and the National Council for Scientific and Technological Development.