Artificial sweeteners frequently make headlines. According to some reports, they pose a greater health risk than the sugar they replace. This perspective, however, is not always backed by scientific evidence. Despite this, the narrative persists in media reports, often overshadowing what data actually reveals.
Recently, artificial sweeteners have been spotlighted again, with claims that they accelerate cognitive decline. A recent study identified six such ‘hazardous chemicals’, including popular ones like xylitol and aspartame, which are suggested to potentially expedite brain degeneration.
The study has been widely reported by various media outlets. Although ScienceAlert has not specifically covered this paper, they frequently discuss the latest research on artificial sweeteners. Despite being published in September 2025, the study continues to garner attention in the latter half of 2026.
“This is all made especially remarkable given that it doesn’t really show any issues from artificial sweeteners at all.” – epidemiologist Gideon Meyerowitz-Katz
The study itself is a straightforward observational analysis. Researchers utilized data from the ELSA dataset, involving Brazilian public servants, to track cognitive function over time using standardized tests. Participants completed detailed questionnaires about their lifestyle, including a food frequency questionnaire, which assesses reported rather than actual dietary intake. This distinction is crucial and will be revisited.
The researchers examined the relationship between self-reported sweetener consumption, as derived from these questionnaires, and cognitive decline across four different scales.
Over the study’s eight-year span, individuals in the highest third of sweetener consumption exhibited a slightly higher degree of brain aging compared to those in the lowest third.
However, this research is subject to typical limitations of observational studies. A significant issue is that food frequency questionnaires measure perceived, not actual, food intake, and individuals often misreport their consumption habits.
Most questionnaires ask about the last 12 months, though people often struggle to accurately recall their dietary history over such an extended period. Additionally, the study assumes dietary habits remained constant throughout its duration. With only a single questionnaire available, any changes in participants’ diets during the study went undetected.
As noted in letters to the journal, there are also doubts about the biological plausibility of the findings. Some sweeteners are natural substances, one is an uncommon form of sugar, and they all possess distinct molecular structures. It is highly improbable for these diverse chemicals to affect the brain in the same way.
There’s also the issue of reverse causality, suggesting that individuals experiencing cognitive decline due to conditions like diabetes or heart disease might have been more inclined to use artificial sweeteners at the study’s outset. This complication proves difficult to address with the study’s analytical approach.
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It’s notable that at least one of the authors’ analyses found no connection between sweeteners and brain aging. In supplementary statistical models, a full case analysis showed no correlation between sweetener use and cognitive decline. This contrasts with other analyses that excluded participants for various reasons, such as having Parkinson’s disease or reporting abnormally high caloric intake.
Further issues arise from independent reviewers who identified obvious mathematical errors in the paper. Despite a correction, some mistakes persist, including inaccuracies in the confidence interval presented in the abstract.
Ultimately, this research sheds little light on the relationship between artificial sweeteners and brain health. At most, the study suggests potential negative effects, but these depend on which analysis one considers credible.
Related: Artificial Sweetener Can Trick Your Brain Into Feeling More Hungry
It’s more probable that the widespread media attention is based on mathematical inaccuracies. Despite years of warnings about artificial sweeteners, evidence suggests they are thoroughly tested and generally safe.
Some studies even indicate that artificially sweetened drinks might be healthier than water in certain respects, although such findings likely reflect a preference for lower-calorie alternatives over sugary beverages.
Despite their negative reputation, data convincingly shows that artificial sweeteners are at least a better option than sugar.
Gideon Meyerowitz-Katz is an epidemiologist working in chronic disease in Sydney, Australia. He writes a regular health blog covering science communication, public health, and what that new study you’ve read about actually means. He’s previously helped ScienceAlert break down the real science behind the most viral papers.
This article was fact-checked and edited by Rebecca Dyer. While we pride ourselves on our process, we are only human. If you spot a mistake, please let us know.
