A study published in Neurology on July 18, 2026, has linked higher consumption of common sugar substitutes to accelerated cognitive decline and faster memory loss in adults.
The strongest associations were observed among individuals under age 60 and those with diabetes.
Researchers monitored 12,772 Brazilian adults with an average age of 52 over approximately eight years.
They evaluated the effects of seven low- and no-calorie sweeteners commonly found in diet beverages, yogurt, and low-calorie desserts.
Participants who consumed the highest daily amounts of these sweeteners experienced a 62% faster rate of decline in memory and thinking skills compared to those with the lowest intake.
This effect is equivalent to roughly 1.6 additional years of brain aging.
Specific Sweeteners and Their Impact
The study assessed seven compounds: aspartame, saccharin, acesulfame K, erythritol, xylitol, sorbitol, and tagatose.
Except for tagatose, every individual sweetener was separately tied to accelerated cognitive decline, particularly affecting memory retention, verbal fluency, and processing speed.
"Low- and no-calorie sweeteners are often seen as a healthy alternative to sugar, however our findings suggest certain sweeteners may have negative effects on brain health over time," said study author Dr. Claudia Kimie Suemoto of the University of São Paulo.
Participants in the highest intake group consumed an average of 191 milligrams per day of sweeteners—equivalent to the aspartame content in one can of diet soda.
Those in the lowest group averaged 20 milligrams daily.
Middle-tier consumers showed a 35% faster rate of cognitive decline, corresponding to about 1.3 years of accelerated aging.
"While we found links to cognitive decline for middle-aged people both with and without diabetes, people with diabetes are more likely to use artificial sweeteners as sugar substitutes," Suemoto said.
"More research is needed to confirm our findings and to investigate if other refined sugar alternatives, such as applesauce, honey, maple syrup or coconut sugar, may be effective alternatives," she added.
Researchers emphasized that as an observational study, the findings establish a statistical connection rather than direct cause and effect.
Dietary data was self-reported by participants through questionnaires administered at the start of the monitoring period.
The health impact of beverages remains a focus of public health research. Sugar-sweetened drinks represent the largest source of added sugar in the American diet.
A systematic review for the 2025–2030 Dietary Guidelines for Americans associated sugary beverage consumption with increased risks of type 2 diabetes, obesity, and systemic inflammation.
Independent research has also highlighted systemic challenges in beverage science transparency.
A 2016 review led by Dr. Dean Schillinger at the University of California, San Francisco, analyzed 60 studies on sugary drinks and metabolic disease.
All 26 studies reporting no adverse health link were funded by the beverage industry.
"This industry seems to be manipulating contemporary scientific processes to create controversy and advance their business interests at the expense of the public's health," Schillinger said.
Industry advocacy groups maintain that their supported research meets rigorous scientific standards. Health researchers recommend prioritizing plain water and whole foods to minimize potential neurological and metabolic risks.
"We are in a public health war with diabetes right now. In every war there is propaganda...
we are being played," Schillinger said.
