Popular Artificial Sweeteners Linked to Faster Brain Aging in Large Observational Study
核心洞察
A longitudinal study of 12,772 Brazilian adults found that the highest third of artificial sweetener consumers experienced cognitive decline (搜索) equivalent to roughly 1.6 additional years of brain aging over eight years.
Six sweeteners—aspartame, saccharin, acesulfame K (搜索), erythritol, sorbitol, and xylitol—showed links with faster cognitive decline (搜索), while tagatose did not.
The study, published in Neurology, cannot establish causation due to its observational design, reliance on self-reported food frequency questionnaires, and identified mathematical errors that remain uncorrected.
A new observational study published in Neurology has raised questions about the long-term brain health effects of several widely used artificial sweeteners, though independent experts caution that the findings are far from conclusive and may be undermined by methodological weaknesses.
Researchers led by Dr. Claudia Kimie Suemoto at the University of São Paulo (搜索) analyzed data from 12,772 adults with an average age of 52 participating in the ELSA-Brasil longitudinal cohort study. Over eight years of follow-up, participants completed standardized cognitive tests measuring memory, language, concentration, and processing speed, while their sweetener intake was estimated from a single food frequency questionnaire administered at baseline.
The study found that participants in the highest third of sweetener consumption experienced faster declines in overall cognitive performance compared to those in the lowest third—a difference the authors equated to approximately 1.6 additional years of brain aging. The association was particularly pronounced in adults younger than 60 and in individuals living with diabetes (搜索). Six sweeteners—aspartame, saccharin, acesulfame K (搜索), erythritol, sorbitol, and xylitol—showed links with faster decline, while tagatose did not.
Methodological Concerns and Scientific Debate
Despite widespread media coverage framing the findings as evidence that artificial sweeteners accelerate cognitive decline (搜索), epidemiologists have identified significant limitations that undermine the study's conclusions.
Gideon Meyerowitz-Katz, an epidemiologist working in chronic disease in Sydney, Australia, noted that the research "doesn't really show any issues from artificial sweeteners at all." He pointed out that food frequency questionnaires measure what people think they eat rather than actual intake, and that the analysis assumed participants' diets remained unchanged over the entire eight-year study period based on a single baseline questionnaire.
The study also faces questions of reverse causality: individuals already experiencing cognitive decline (搜索) due to conditions such as diabetes (搜索) or heart disease may have been more likely to consume artificial sweeteners at baseline, making it difficult to disentangle cause from effect.
Perhaps most critically, at least one analysis relegated to the supplementary appendix—the full case analysis including all original cohort members—found no relationship between sweetener consumption and brain aging. The analysis that garnered media attention excluded participants for reasons including Parkinson's disease and unusually high caloric intake.
Independent reviewers have also identified mathematical errors in the paper. Despite a published correction, errors reportedly remain, including a mistake in the confidence interval reported in the abstract.
Biological Plausibility Questioned
Letters to the journal have raised concerns about the biological plausibility of the findings. The sweeteners studied include natural substances, a rare form of sugar, and molecules with vastly different chemical structures. Experts argue it would be extremely unlikely for all of these disparate compounds to produce the same effect on the brain.
The researchers themselves acknowledged that their study cannot establish causation. Potential mechanisms—including influences on gut bacteria, inflammation, or energy metabolism—remain speculative and unproven.
Clinical Context
Health experts continue to recommend reducing excessive added sugar intake while cautioning against overreliance on highly processed foods, whether sugar-sweetened or artificially sweetened. As Meyerowitz-Katz noted, "the data show quite convincingly that they are, at least, better for you than sugar."
The study's strengths include its large sample size, long follow-up period, and detailed cognitive testing. Its central weakness is the observational design, which precludes causal inference. Until randomized clinical trials are completed, the findings should be interpreted as evidence of an association rather than proof that artificial sweeteners harm memory.