Brussels, 4 September 2025: Following the publication of the new study, “Not so sweet: Some sugar substitutes linked to faster cognitive decline,” in Neurology on 3 September 2025, the International Sweeteners Association (ISA) urges a careful interpretation of its findings. While the study has garnered media attention, it is essential to place its results within the broader, established scientific consensus on sweeteners safety.
This research is an observational study, which can only show a statistical association, not a direct cause-and-effect relationship. The reported link between sweetener consumption and cognitive decline does not prove that one causes the other. As with all such research, the findings may be influenced by many confounding factors, including overall dietary patterns, lifestyle choices and other health conditions. The study’s own authors acknowledge this, cautioning against drawing causal conclusions.
It is also important to note the study’s specific limitations. The results are inconsistent across different age groups and varied by diabetes status, which raises questions about biological plausibility. Also, the study relies on a self-reported method for dietary data collected only once at baseline 8 years ago, which is often inaccurate, can introduce significant bias, and does not consider changes in dietary habits and product formulations over time. Furthermore, all sweeteners were aggregated in a single value from both high-intensity sweeteners and polyols, while we know they all have very different properties and approved use levels. In practice, the “combined sweetener” intake was dominated by polyols that are used in higher quantities, while the intake of aspartame, acesulfame-K and saccharin was very low even for the high consumption group (at the order of 1-2% of the respective Acceptable Daily Intakes). These values suggest a limited and narrow range of exposure and a high likelihood of floor effects that can bias results. Floor effects are known to distort statistical models, leading potentially to false positives[1].
The safety of low/no calorie sweeteners has been consistently confirmed by leading global health authorities. These include the European Food Safety Authority (EFSA), the U.S. Food and Drug Administration (FDA), and the Joint Expert Committee on Food Additives (JECFA) of the World Health Organization (WHO) and the Food and Agriculture Organization (FAO). These organisations conduct comprehensive safety assessments based on the totality of scientific evidence, not just a single study.
Sweeteners provide a safe and effective way to reduce sugar and calorie intake, a key public health goal for managing conditions such as obesity and type 2 diabetes. By offering a sweet taste without the calories, they help consumers adhere to dietary guidelines that recommend reducing free sugars.
The ISA remains committed to providing science-based information on low/no calorie sweeteners. We advocate for a holistic view of the scientific evidence, which consistently demonstrates that approved sweeteners are a safe and useful tool for public health.
Read more about the benefits of low/no calorie sweeteners on the International Sweeteners Association website: https://www.sweeteners.org/en.
[1] Drewnowski A, Fulgoni VL 3rd. Should Atypical and Non-Representative Studies Such as NutriNet Santé Be Used to Drive Public Health Policy? Nutrients. 2025 Aug 8;17(16):2581. https://doi.org/10.3390/nu17162581.