Quick Summary
- Artificial sweeteners like aspartame and saccharin may speed up brain ageing by 1.6 years.
- Study followed 13,000 adults in Brazil for eight years.
- High consumers saw a 62% faster decline in memory and word recall.
- Even moderate intake (1 diet soda daily) may raise diabetes risk by 38%.
- These sweeteners are found in sodas, flavored waters, desserts, and energy drinks.
- Experts suggest limiting intake and considering natural alternatives.
Artificial sweeteners have long been marketed as a healthier alternative to sugar. But new research suggests they may come with unexpected risks. A study published in the journal Neurology warns that regular consumption of low- and no-calorie sweeteners (LNCs) like aspartame and saccharin may accelerate brain ageing by as much as 1.6 years, impairing memory and word recall. Artificial Sweeteners Linked to Faster Brain Ageing, Study Finds
What the Study Found
Researchers analysed nearly 13,000 adults in Brazil, with an average age of 52, over a period of eight years. Participants’ dietary habits were recorded, and their cognitive abilities were tested three times during the study period.
Key findings include:
- 62% faster decline in global cognitive ability among people who consumed the most artificial sweeteners.
- This decline equated to 1.6 years of additional brain ageing.
- The highest-tier consumers averaged 191 milligrams per day—about one teaspoon of sweetener.
- For context, a single can of diet soda contains 200–300 milligrams of artificial sweeteners, according to the World Health Organization (WHO).
Even moderate consumers were affected. Those in the middle tier experienced a 35% faster decline, roughly equivalent to 1.3 years of brain ageing compared to the lowest consumers.
Where Are Artificial Sweeteners Found?
Artificial sweeteners aren’t limited to diet soda. The study identified them in a wide range of products, including:
- Flavoured waters
- Low-calorie desserts
- Energy drinks
- Sugar-free snacks and gum
This widespread presence means many consumers may be taking in more sweeteners than they realize.
Why Does This Matter?
Cognitive decline is a key risk factor for dementia and other neurodegenerative conditions. The study suggests that even small daily intakes of artificial sweeteners may have long-term consequences for brain health.
While the exact mechanisms remain unclear, researchers point to potential effects on metabolism, gut microbiota, and neural pathways that regulate memory and learning.
Artificial Sweeteners and Diabetes Risk
This is not the first study to raise red flags about sugar substitutes.
- Australian research (August 2025) found that drinking just one can of diet soda per day could increase the risk of developing type 2 diabetes by 38%.
- Interestingly, the risk was higher for artificially sweetened soft drinks than for regular sugary drinks, which were associated with a 23% higher risk.
- Importantly, the link between diet sodas and diabetes remained strong even after adjusting for body weight, suggesting sweeteners may have direct effects on metabolism beyond calorie intake.
Should You Avoid Artificial Sweeteners?
Health experts caution against overreaction, but the findings warrant attention. While artificial sweeteners may help reduce sugar intake, frequent use could come at the cost of long-term brain health.
A balanced takeaway:
- Occasional consumption is unlikely to be harmful.
- Heavy, daily intake—such as multiple cans of diet soda—may increase health risks.
- Natural alternatives (like honey or stevia in moderation) could be safer options for those looking to cut sugar.
The Bigger Picture
Artificial sweeteners were once hailed as the answer to rising obesity and diabetes rates. But emerging research paints a more complicated picture. Instead of being a harmless sugar substitute, they may introduce new metabolic and cognitive risks.
As one researcher noted:
“Our findings suggest the possibility of long-term harm from low- and no-calorie sweeteners, particularly artificial LNCs and sugar alcohols, on cognitive function.”
Future studies will need to confirm these links and uncover the biological mechanisms at play. But for now, the message is clear: moderation is key.