Brain Health and Artificial Sweeteners: Does High Consumption Accelerate "Cognitive Aging"?

1. What's New: The Core of the News

In September 2025, the British newspaper The Independent reported that a "diet high in artificial sweeteners is associated with decline in brain health (faster cognitive decline)." The basis for this is a large longitudinal study published in the neurology journal 'Neurology,' involving 12,772 adults in Brazil (average age 52). Over up to 8 years, the study tracked the intake of low- and no-calorie sweeteners in the diet and the progression of cognitive tests such as verbal fluency, memory, and processing speed. The Independent

2. The Seven Sweeteners Evaluated

The study focused on the following seven types, all commonly found in diet drinks, flavored waters, energy drinks, sugar-free sweets, yogurts, protein bars, and gums.

• Aspartame

• Saccharin

• Acesulfame-K

• Erythritol

• Xylitol

• Sorbitol

• Tagatose

As a result, aspartame/saccharin/acesulfame-K/erythritol/xylitol/sorbitol were associated with faster cognitive decline, while tagatose was deemed not related. News - Medical

3. How Much Intake Strengthened the Association: Intake Levels and Impact Scale

In an analysis dividing participants into three groups based on total intake, the highest intake group (average 191mg/day) was estimated to have a 62% faster overall cognitive decline compared to the lowest intake group (average 20mg/day). The conversion value in the statistical model corresponds to "1.6 years" of cognitive aging. Furthermore, the intermediate intake group also showed a 35% faster decline. As a reference, it is noted that one can of diet soda ≈ approximately 200mg of aspartame. The Independent

Differences by Age and Underlying Conditions

Under 60, the association was clearer, and there was a tendency for a stronger association in people with diabetes. On the other hand, no clear association was confirmed in those aged 60 and over. News - Medical

4. What is the Mechanism? (Still Hypothetical)

The study is an observational study and does not prove causality. Possible explanations include:

• effects on the nervous, immune, and metabolic systems via changes in the **gut microbiota (microbiome)**,

• indirect effects on cerebrovascular and metabolic systems

  ,

• confounding factors such as a lifestyle dependent on "ultra-processed foods" (sleep, physical activity, intake of other additives), but no definitive explanation is available yet. In the future, biomarker, imaging studies, and intervention trials are needed. Medical News Today

5. Relation to Safety Evaluation: How Regulatory Authorities View It

The FDA has approved the use of major artificial sweeteners as food additives, deeming them safe for the general population within appropriate intake ranges. The current findings show an "association" with long-term cognitive function as an outcome, and do not immediately overturn the regulatory safety conclusions. Conversely, as new insights have emerged for long-term outcomes, research on long-term effects should be expanded. The Independent

6. "Practical Measures" Japanese Consumers Can Take

(1) Understand "Where It Is Used"
Check the ingredient labels for

• aspartame (L-phenylalanine compound), sodium saccharin, acesulfame K, sucralose,

• sugar alcohols (erythritol, xylitol, sorbitol, etc.),

• and tagatose (sometimes used as a lactose-derived component).
  Pay special attention to drinks, sweets, and gums labeled as **"sugar-free"** or **"zero-calorie"**, protein-based snacks, and functional beverages. The Independent

(2) Manage the "Total Amount"
Combine and understand the total from "drinks, snacks, seasonings, and supplements." For example, if replacing with diet drinks becomes a daily habit, the total amount can easily accumulate. Use water, sparkling water, and unsweetened tea as a base, and gradually switch to flavoring with sliced citrus or herbs to reduce reliance on sweetness. Medical News Today