The key facts

  • Among participants under 60, high sweetener consumption was associated with faster decline in verbal fluency and overall cognitive scores
  • The association was found for six of the seven substances studied — all except tagatose
  • The study is observational: a cause-and-effect relationship has not been proven

What the researchers found

A team involving the University of São Paulo published in the journal Neurology the results of an eight-year observation of residents of Brazil. The analysis included 12,772 people with an average age of about 52 at the start of the study. Participants filled out detailed dietary questionnaires and took tests of memory, verbal fluency, and information processing speed three times. As Gazeta.Ru reports, higher consumption of a number of low-calorie and non-caloric sweeteners was associated with a faster decline in performance on these tests.

Who exactly was affected by the association

The authors assessed total and individual consumption of seven sweeteners: aspartame, saccharin, acesulfame potassium, erythritol, xylitol, sorbitol, and tagatose. These substances are found in beverages, desserts, and other products with reduced sugar content. Among participants under 60, higher total consumption was associated with a faster decline in verbal fluency and overall cognitive scores, while in people aged 60 and over no similar association was found. In the individual analysis, the association was confirmed for six compounds — all of those listed except tagatose; it particularly affected memory and the ability to quickly find words. The nature of the associations differed between people with and without diabetes.

Limitations of the conclusions

The study was observational: the scientists did not assign sweeteners to participants and did not control the diet experimentally. Therefore, the result does not prove that sugar substitutes specifically caused the changes — other dietary habits, health conditions, and lifestyle factors could have influenced it, and the dietary data depended on the participants' own recall. For the reader, this means that we are talking about a statistical association, not proven harm from a specific product; the individual substances and differences between groups were assessed by the authors within the same sample, which allows the results to be compared with each other but does not eliminate the limitations listed above.