Artificial sweeteners have long been the focus of scientific research for their potential health effects. Now, a new study, published in the journal Neurology, adds another dimension to the debate: according to researchers, high consumption of certain low- or zero-calorie sweeteners may be associated with more rapid cognitive decline over time. The analysis found an association between higher intakes of these substances and a more marked decline in performance on tests assessing memory, language, and information processing speed.
The findings have sparked interest because they involve widely available products, used in so-called "light" and "zero" drinks, as well as in numerous foods aimed at those who want to reduce their sugar intake. However, the authors themselves urge caution: the research does not prove that sweeteners cause cognitive decline, but merely identifies an association that needs to be explored further.
What Was Discovered
The study involved 12,772 Brazilian adults with an average age of about 52, followed for about eight years as part of a large population health research project. At the beginning of the study, participants completed questionnaires about their dietary habits, allowing researchers to estimate their consumption of various artificial sweeteners found in foods and beverages. Among those examined were aspartame, saccharin, acesulfame K, erythritol, xylitol, sorbitol, and tagatose. Researchers then divided the participants into three groups based on the amount of sweeteners they consumed daily. The group with the lowest consumption averaged about 20 mg per day, while the group with the highest consumption reached 191 mg per day, an amount roughly equivalent to the amount of aspartame in a can of "zero" or "diet" soda.
Over the years, the participants underwent neuropsychological tests to assess various cognitive functions, including memory, verbal fluency, and information processing speed. Data analysis revealed that those in the highest-consumption group showed a 62% faster cognitive decline than those with the lowest intake. According to the authors, this difference is equivalent to approximately 1.6 years of additional cognitive aging. The association was particularly evident in people under 60 and in those with diabetes. Of all the sweeteners evaluated, tagatose was the only one that did not show a statistically significant association with cognitive decline.
What Does This Research Really Mean?
As interesting as the results are, it's important to interpret them correctly. The study is observational, meaning it can highlight a correlation between two factors, but it cannot prove that one is the cause of the other. In practice, the fact that people who consumed more sweeteners showed greater cognitive decline doesn't necessarily mean that these ingredients were the cause. Other factors, such as the presence of diabetes, body weight, lifestyle, or overall diet quality, could have contributed to the results. Although the researchers adjusted the analyses for many of these variables, the risk that some factors influenced the data cannot be completely ruled out.
It should also be noted that sweetener consumption was reconstructed through food questionnaires completed by participants: this is a widely used tool in nutritional research, but it can be subject to memory errors or an inaccurate estimate of actual quantities consumed. Further research will therefore be needed to understand whether the observed association corresponds to a real effect of these substances on brain health. In the meantime, experts continue to emphasize that cognitive health depends on a combination of factors: following a varied and balanced diet, engaging in regular physical activity, and managing the main cardiovascular and metabolic risk factors remain the most important elements for promoting long-term brain health.
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