A new study published in the journal Neurology has raised concerns about the long-term effects of artificial sweeteners on brain health. Researchers in Brazil tracked the dietary habits of over 12,700 adults over an eight-year period and found that those who consumed the highest levels of low- or no-calorie sweeteners experienced a significantly faster decline in memory and cognitive function.
The study focused on seven commonly used sweeteners: aspartame, saccharin, acesulfame-K, erythritol, xylitol, sorbitol and tagatose. All but tagatose were associated with cognitive decline, particularly in areas such as memory and verbal fluency. Participants who consumed the most sweeteners—equivalent to the amount in a single can of diet soda per day—showed a 62 per cent faster rate of cognitive decline compared to those who consumed the least. This was roughly equal to an additional 1.6 years of brain ageing.
The effect was especially pronounced among individuals under the age of 60 and those with diabetes. According to lead author Professor Claudia Kimie Suemoto of the University of São Paulo, this was unexpected, as older adults are typically at greater risk of dementia and cognitive impairment. Suemoto emphasised that midlife may be a critical period for brain health, making exposure to sweeteners during this time particularly concerning.
While previous studies have linked artificial sweeteners to health issues such as cancer, cardiovascular disease and depression, their impact on cognitive function had not been thoroughly examined until now. The researchers caution that the findings do not establish a direct causal relationship, as the data was based on self-reported dietary intake and did not include all types of sweeteners.
Nevertheless, the results suggest the need for further investigation, including neuroimaging and studies into gut health and inflammation. Suemoto’s team is already conducting follow-up research to explore the underlying mechanisms. She also called for future studies into whether natural alternatives like honey or maple syrup might offer safer options.
The study adds to growing evidence that artificial sweeteners, often marketed as healthier substitutes for sugar, may carry hidden risks to long-term brain health.
