New Research Questions Safety of Popular Sugar Substitutes
Many consumers opt for sugar-free products, believing them to be a healthier alternative. However, recent research involving nearly 13,000 Brazilian adults suggests a concerning link between the frequent consumption of six common low-calorie sweeteners and an accelerated rate of cognitive decline.
The observational study, conducted over approximately eight years, found that participants with the highest intake of these sweeteners experienced a 62% faster decline in overall thinking and memory abilities compared to those who consumed the least. This difference was equivalent to roughly 1.6 additional years of cognitive aging during the study period.
Sweeteners Identified in the Study
Researchers examined seven widely used low- and no-calorie sweeteners found in various processed foods and beverages. Six of these were associated with faster declines in cognitive performance, particularly memory. The sweeteners identified were:
- Aspartame: Commonly found in diet soft drinks and sugar-free products.
- Saccharin: An artificial sweetener used in tabletop sweeteners.
- Acesulfame-K (Acesulfame potassium): Present in beverages and reduced-sugar desserts.
- Erythritol: A sugar alcohol used in low-calorie foods and confectionery.
- Sorbitol: A sugar alcohol often in sugar-free chewing gum and processed foods.
- Xylitol: Another sugar alcohol found in sugar-free gum, mints, and oral-care products.
The seventh sweetener, tagatose, did not show a similar association with cognitive decline in this study, though researchers caution this does not confirm its safety or protective effects.
Study Methodology and Key Findings
The research analyzed data from 12,772 adults in Brazil, with an average age of 52 at the study's outset. Participants completed detailed dietary questionnaires and underwent cognitive assessments at three points over eight years. They were divided into three groups based on their daily sweetener consumption, ranging from an average of 20 milligrams per day for the lowest group to 191 milligrams per day for the highest (equivalent to about one can of diet soda with aspartame).
Beyond the overall 62% faster decline in the highest consumption group, the middle consumption group also experienced a 35% faster decline compared to the lowest. These figures represent differences in cognitive test performance over time, not direct measurements of biological brain age.
Specific Demographics Affected
The association between higher sweetener consumption and faster cognitive decline was particularly pronounced in certain groups:
- Younger Adults: Among participants younger than 60, higher sweetener intake was linked to faster declines in verbal fluency and overall cognitive performance.
- Individuals with Diabetes: The relationship was stronger among people with diabetes, a group that frequently uses artificial sweeteners to manage sugar intake.
Understanding the Implications and Future Research
While this study raises important questions about the long-term effects of low-calorie sweeteners on brain health, it is crucial to understand its limitations. As an observational study, it identifies associations rather than establishing direct cause and effect. Researchers emphasize that these findings do not prove that sweeteners directly damage brain cells or cause memory loss.
It is possible that other lifestyle, dietary, or health-related factors contributed to the observed differences in cognitive performance, despite researchers accounting for variables like age, sex, blood pressure, and cardiovascular disease. Further research is needed to confirm these findings, investigate specific biological mechanisms, and explore whether individual sweeteners affect cognitive function differently.
The study authors, including Claudia Kimie Suemoto of the University of São Paulo, recommend more investigation into refined sugar alternatives like applesauce, honey, maple syrup, and coconut sugar as potential effective substitutes.