TL;DR
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A study published in Neurology linked higher consumption of six low- and no-calorie sweeteners with faster declines in cognitive test performance among adults in Brazil. The observational findings do not prove the sweeteners caused the changes, and tagatose was not associated with decline in this study.
A study published in Neurology has linked higher consumption of six low- and no-calorie sweeteners with faster declines in memory and thinking skills among adults in Brazil, but it does not show that the sweeteners caused those changes. Researchers tracked 12,772 adults for about eight years; the association was stronger among people with diabetes and those younger than 60.
Researchers analyzed participants’ reported diets and cognitive test results over the study period. At the start, participants were 52 years old on average and answered questionnaires about the foods and drinks they had consumed during the prior year. The team estimated daily intake of seven sweeteners and divided participants into three groups. Average intake ranged from 20 milligrams per day in the lowest group to 191 milligrams per day in the highest. The report says 191 milligrams is roughly the amount of aspartame in one can of diet soda.
Participants completed tests at the beginning, middle and end of the study. These assessed memory, language and processing speed, including word recall, verbal fluency and working memory. After adjusting for factors including age, sex, high blood pressure and cardiovascular disease, the highest-intake group had a decline in overall cognitive test performance that was 62% faster than the lowest-intake group. The researchers equated that difference to about 1.6 additional years of cognitive aging over the study period. The middle-intake group had a 35% faster decline, equated to about 1.3 additional years.
Those results refer to changes in test performance, not a direct measurement of biological brain aging. The six sweeteners associated with faster decline were aspartame, saccharin, acesulfame-K, erythritol, sorbitol and xylitol. Researchers did not find an association for tagatose. Sorbitol had the highest average intake among the seven substances, at 64 milligrams per day. The report does not establish that tagatose protects cognitive health or is safer.
What the Cognitive Test Results Show
The findings matter because low- and no-calorie sweeteners are widely used in products such as diet sodas, flavored waters, energy drinks, yogurt and low-calorie desserts, as well as sold for home use. Some consumers choose them to reduce sugar intake, including people managing diabetes. The study raises a question about whether the health trade-offs of these products have been fully understood, but it does not establish that consumers should stop using them.
The reported differences are group-level associations, not predictions about what will happen to any individual. A faster average decline on cognitive tests does not mean that every person who consumes these ingredients will develop memory problems. Nor does the study demonstrate that the substances directly damage the brain. The results are a reason for further research, rather than proof of harm or a basis for a specific dietary recommendation.
The stronger association reported among participants with diabetes is relevant because sweeteners are often used as substitutes for sugar. But the finding does not show that diabetes itself makes sweeteners harmful, or explain why the association differed between groups. People making dietary decisions for diabetes or other health needs should discuss them with a qualified health professional.
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How Researchers Measured Sweetener Intake
The research, summarized by ScienceDaily, examined data from adults in Brazil and assessed seven ingredients commonly used to provide sweetness with fewer or no calories. Participants reported their diets at the study’s outset, while cognitive testing took place at three points across roughly eight years. This design allowed researchers to compare reported intake with changes in test performance over time.
The study’s headline percentage compares the rate of cognitive test decline in the highest-intake group with the lowest-intake group after statistical adjustments. It is not a claim that brain aging itself was measured directly. The report also gives a comparison for the middle-intake group, but does not provide enough detail in the supplied material to interpret the full range of each person’s exposure or the precision of the estimates.
In comments reported by ScienceDaily, study author Claudia Kimie Suemoto, of the University of São Paulo, said the findings challenge the assumption that these products are automatically a healthy alternative to sugar. The research remains observational: adjusting for several known factors cannot rule out every difference between people who consume more sweeteners and those who consume less.
“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.”
— Claudia Kimie Suemoto, study author at the University of São Paulo, as quoted by ScienceDaily
Cause and Individual Risk Remain Unknown
The study cannot determine whether sweetener consumption caused cognitive test scores to decline. Because researchers observed dietary habits rather than assigning participants to consume particular sweeteners, other unmeasured factors could help explain the association. The reported adjustments addressed several influences, including age and cardiovascular risks, but do not remove the limits of an observational study.
Diet was estimated from questionnaires about the year before the study began. The supplied report does not clarify how well those initial reports represented participants’ intake throughout follow-up, or provide detailed results for each sweetener’s individual association. It also does not give enough information to assess the size and precision of all subgroup findings. The absence of an association for tagatose is not evidence that it prevents decline.
Researchers reported stronger links among adults younger than 60 and people with diabetes, but no similar association among participants older than 60. The reason for those differences is not established. The findings also concern cognitive test performance; they do not show that participants developed dementia or another diagnosed condition.
Further Studies Needed to Test the Link
The next step is further research to see whether the association appears in other populations and study designs. Studies that repeatedly measure diet and cognition could help clarify whether the relationship persists over time, while research examining individual sweeteners could test whether the substances differ in their associations. The supplied report does not identify a planned follow-up study or a date for additional results.
For now, the findings do not establish a new dietary rule. They add a potential cognitive-health question to ongoing discussion about low-calorie substitutes, especially for people who use them regularly or to manage diabetes. The study’s results should be read as an observed association, not proof that reducing or avoiding a particular sweetener will prevent cognitive decline.
Key Questions
Which six sweeteners were linked to faster cognitive decline?
The study associated faster declines in cognitive test performance with aspartame, saccharin, acesulfame-K, erythritol, sorbitol and xylitol. It found no association for tagatose.
Does the study prove that sweeteners cause memory loss?
No. Researchers found an association in an observational study. The results do not establish that sweeteners caused cognitive changes or that any individual consumer will experience memory problems.
What did the 62% figure mean?
After adjustment for several factors, the highest-intake group’s decline in overall cognitive test performance was 62% faster than the lowest-intake group’s over the study period. Researchers equated the difference to about 1.6 additional years of cognitive aging; biological brain aging was not directly measured.
Were the findings the same for all participants?
No. The association was stronger among adults younger than 60 and among people with diabetes. Researchers did not find a similar association among participants older than 60. The reasons for these differences remain unclear.
Does the tagatose result mean it is safer?
No. The study found no association between tagatose intake and cognitive decline, but that does not prove tagatose protects the brain or is safer than the other sweeteners.
Source: sciencedaily.com
