Artificial sweeteners have in recent years become an inseparable part of the modern diet. They are found in diet beverages, chewing gum, yogurts, protein bars, “keto” products, and even in medications and dietary supplements. For many—especially people with diabetes or those trying to reduce sugar intake—they are perceived as a smart and healthier solution.
However, a new study published in the prestigious medical journal Neurology raises a troubling possibility: High and prolonged consumption of artificial sweeteners may be associated with accelerated deterioration in memory and cognitive abilities.
What did the study examine?
The study followed 12,772 adults with an average age of 52 over approximately 8 years. At the outset, participants filled out detailed questionnaires about their dietary habits—including sweetener consumption—and later underwent a series of cognitive tests assessing memory, language, attention, and complex thinking.
The researchers divided participants into three groups according to daily sweetener intake:
• Low group: Approximately 20 mg per day
• Medium group
• High group: Approximately 191 mg per day—an amount roughly equivalent to one can of a diet beverage
People in the high-consumption group experienced a 62% faster cognitive decline compared to the low group. In terms of brain aging, this represents an effect equivalent to about 1.6 additional years of aging. The medium group also showed accelerated decline, though more moderate.
Among people with diabetes—the decline was even more pronounced.
The sweeteners linked to cognitive decline
The study identified a connection to six particularly common sweeteners:
• Aspartame: The common sweetener in diet beverages, yogurts, and other dairy products
• Saccharin: Found in the sweetener Sweet'N Low
• Acesulfame: Found in candies, baked goods, and the sweetener Equal
• Erythritol: Commonly found in “keto” products and in the sweetener Truvia
• Sorbitol: Found in candies and in quite a few medications
• Xylitol: Found in chewing gum and oral hygiene products
The researchers emphasized that the findings “suggest the possibility of long-term impairment in cognitive function,” but do not prove direct causality.
So do sweeteners cause brain damage?
This is where scientific caution comes in. This is an observational study—meaning one that finds an association but cannot determine that sweeteners are the direct cause of cognitive decline.
The study did not examine important variables such as sleep quality, physical activity, stress, or overall diet quality—all known factors that affect brain health.
However, the researchers propose several possible biological mechanisms:
Brain inflammation and the gut–brain axis
According to Dr. Claudia Suemoto, one of the study’s leaders, animal studies show that certain sweeteners may:
• Promote inflammation in the brain
• Alter the composition of gut bacteria
• Damage the blood–brain barrier
Such changes may affect memory, concentration, and thinking ability.
“The brain without fuel”
Neurologists explain that sweeteners do not provide glucose—the brain’s primary energy source. A diet rich in sweeteners but low in natural carbohydrates could, theoretically, impair brain function over time.
The effect is stronger among people with diabetes, because they:
• Use sweeteners more frequently
• Are already at increased risk for damage to blood vessels and the brain
• Are more sensitive to metabolic changes and inflammation
The combination of diabetes and high sweetener consumption may place an even greater burden on the system.
In light of the findings—what do the researchers recommend?
The experts are not calling for a total boycott, but for balance and awareness.
• Occasional use: Probably safe
• High daily consumption: Worth thinking twice about
• Preference for whole foods: Fruits, nuts, grains
• Reducing consumption of diet beverages as a regular habit
• Maintaining sleep, physical activity, and social connections—proven factors for brain health
Bottom line: Artificial sweeteners may help reduce sugar, but they are not necessarily “free.” The new study does not determine that one must stop using them—but it certainly suggests pausing, reviewing habits, and asking whether what is considered a healthy solution truly serves us in the long term.