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- What the study measured and who was tracked
- Which sweeteners were included in the analysis
- How much faster did brains appear to age?
- Possible explanations: how sweeteners could affect the brain
- Practical context: where these sweeteners appear in diets
- What the authors recommend and future lines of research
- What consumers should take away now
A large Brazilian study now suggests that the sweeteners in many “diet” drinks and low-calorie snacks might speed up cognitive aging. The research followed more than 12,500 adults for eight years and found notable declines in memory and processing speed tied to common artificial sweeteners.
What the study measured and who was tracked
Researchers enrolled 12,525 adults. The group’s average age was 52. Over eight years, participants completed detailed food and drink questionnaires.
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Cognitive performance was measured three times. Tests evaluated processing speed, memory retention, and word recall. Scientists then grouped participants by how much artificial sweetener they consumed.
Which sweeteners were included in the analysis
- Aspartame
- Saccharin
- Acesulfame-K
- Erythritol
- Xylitol
- Sorbitol
- Tagatose
All but one of these sweeteners showed possible links to declines in mental skills. Tagatose was the only sweetener not connected to reduced cognitive function in this study.
How much faster did brains appear to age?
After adjusting for age, sex, and major health risks, the highest sweetener consumers showed faster decline. They experienced about 1.6 years more cognitive aging than the lowest consumers.
The middle-intake group declined at a slightly lower pace, roughly 1.3 years faster than the low-intake group. These differences translate to a meaningful effect on everyday thinking and recall.
Stronger effects in younger adults and those with diabetes
Participants under 60 who consumed more artificial sweeteners had sharper drops in verbal fluency and overall mental sharpness. In addition, people with diabetes faced the steepest declines across ages.
Diabetes amplified the cognitive associations, regardless of a person’s age. That pattern raises concerns because many people with diabetes use sweeteners as sugar substitutes.
Possible explanations: how sweeteners could affect the brain
Researchers and clinicians point to a few plausible pathways. Artificial sweeteners may:
- Alter the gut microbiome and its signaling to the brain.
- Influence metabolic and insulin responses that affect cognition.
- Contribute to vascular stress, which harms brain blood flow.
- Promote chronic inflammation that impairs neural function.
Previous work has already tied some sweeteners to increased cardiovascular risk. Those vascular links could partly explain cognitive effects.
Practical context: where these sweeteners appear in diets
Artificial sweeteners appear in many processed items. Common sources include diet sodas, sugar-free desserts, low-calorie snacks, and some tabletop sweeteners.
Manufacturers designed many synthetic sweeteners to be far sweeter than sugar. That allowed smaller amounts to achieve the desired taste.
- People trying to lose weight often choose “diet” products.
- People with diabetes may prefer sweeteners to avoid blood sugar spikes.
- Consumers may assume “zero calorie” equals harmless.
But perceived benefits do not rule out long-term harms for the brain.
What the authors recommend and future lines of research
Study investigators urge more research into alternatives to refined sugar and refined sweeteners. They suggest looking at natural substitutes and less-processed options.
Possible natural alternatives worth testing include applesauce, honey, maple syrup, and coconut sugar. Researchers want to know if those options carry lower risks for cognitive decline.
The lead author noted that low- and no-calorie sweeteners are often marketed as healthier than sugar. Yet the new findings raise questions about their long-term effects on brain health.
What consumers should take away now
Experts did not call for an immediate ban, but they warn of caution. Individuals who use diet sodas and many sugar-free products should be aware of emerging evidence.
- Monitor intake of artificial sweeteners.
- Discuss alternatives with health professionals, especially if diabetic.
- Favor whole, minimally processed foods when possible.
As scientists pursue longer and more detailed studies, the balance of benefits and risks for artificial sweeteners will become clearer.
