People who consumed the highest levels of certain artificial sweeteners — equivalent to just one diet soda a day — saw a significant decline in their ability to remember and recall words when compared to people who consumed the lowest levels, a new study found.
“People who consumed the most low- or no-calorie sweeteners showed a 62% faster global cognitive decline than those who consumed the lowest amount — that’s the equivalent of 1.6 — years of brain aging,” said lead study author Dr. Claudia Kimie Suemoto, an associate professor of geriatrics and director of the Biobank for Aging Studies at the University of São Paulo’s Medical School in Brazil.
People in the highest tier consumed an average of 191 milligrams, or about 1 teaspoon, of artificial sweeteners each day. To put that into perspective, one can of diet soda sweetened with aspartame contains around 200 to 300 milligrams, according to the World Health Organization.
A middle tier of people consumed an average of 66 milligrams of artificial sweeteners a day, with the lowest consumption at only 20 milligrams a day, according to Suemoto.
“Participants in the middle tier had a 35% faster rate of global cognitive decline — which is about 1.3 years of aging — than people who consumed the lowest amount of these sweeteners,” she said. “Now, the study is only observational — I cannot say to you that artificial sweeteners cause cognitive decline. We do know, however, that these sweeteners are associated with worse cognitive trajectories.”
Cognitive aging worse for people with diabetes
Researchers analyzed the diet and cognitive abilities of nearly 13,000 Brazilians between the ages of 35 and 75 participating in the Brazilian Longitudinal Study of Adult Health.
Dietary information was collected at the start of the study, or baseline, and a battery of cognitive tests were administered three times over an average of eight years. The tests accessed verbal fluency, working memory, word recall and processing speed.
Working memory is the ability to hold information needed to accomplish complex mental tasks such as learning, reasoning and problem-solving. It’s often measured by asking people to remember certain words or numbers in a series. Verbal fluency is the ability to rapidly and spontaneously produce appropriate words when speaking. It’s often measured by asking people to name as many words as they can which start with a specific letter.
If a person had diabetes, the decline in memory and global cognition was even more pronounced, Suemoto said, likely because their overall exposure may be higher than people without the condition.
