A long-term study of Brazilian adults found that higher intake of several widely used artificial sweeteners was linked to faster cognitive decline, especially in people under 60 and those with diabetes.
Swapping sugar for artificial sweeteners is often framed as an easy health win, but a large new study suggests the story may be more complicated for the brain. Researchers reporting in Neurology, the medical journal of the American Academy of Neurology, found that heavier use of certain sugar substitutes was tied to a faster drop in memory and thinking over time. The pattern was strongest among people with diabetes.
The study does not show that sweeteners directly damage the brain. Instead, it highlights an association that remained even after researchers accounted for major health factors that can affect cognition.
The team looked at seven widely used sweeteners: aspartame, saccharin, acesulfame-K, erythritol, xylitol, sorbitol, and tagatose. These ingredients show up most often in ultra-processed foods and drinks such as flavored water, soda, energy drinks, yogurt, and low-calorie desserts, and some are also sold as standalone sweeteners.
“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 Claudia Kimie Suemoto, MD, PhD, of the University of São Paulo in Brazil.
Study Design and Participant Details
To explore long-range effects, the researchers followed 12,772 adults from across Brazil for about eight years. Participants were 52 years old on average.
At the start, participants completed detailed diet questionnaires covering what they ate and drank over the prior year. Researchers then grouped people based on how much total artificial sweetener they consumed. The lowest intake group averaged 20 milligrams per day (mg/day). The highest intake group averaged 191 mg/day, which for aspartame is about the amount found in one can of diet soda. Among the individual sweeteners, sorbitol stood out with the highest average intake at 64 mg/day.
Participants also took cognitive tests at the beginning, middle, and end of the study. These assessments tracked several skills that tend to change with aging and brain health, including how quickly someone can find words, how well they can hold information in mind, how easily they can recall words later, and how fast they process information.
After adjusting for factors such as age, sex, high blood pressure and cardiovascular disease, the researchers found that the highest intake group declined 62% faster in overall thinking and memory than the lowest intake group. The difference was roughly comparable to about 1.6 years of aging. The middle intake group also declined faster than the lowest intake group, with a 35% faster drop, about the equivalent of 1.3 years of aging.
Differences by Age and Diabetes Status
When the data were analyzed by age, a clearer pattern emerged among participants younger than 60. In this group, those who consumed the most sweeteners experienced steeper drops in verbal fluency and overall cognitive performance compared with those who consumed the least. No significant association was observed among adults older than 60.
The relationship between sweetener intake and cognitive decline was also stronger in participants with diabetes than in those without the condition.
Looking at individual sweeteners, higher consumption of aspartame, saccharin, acesulfame-k, erythritol, sorbitol and xylitol was linked to faster declines in overall cognitive function, especially memory. Tagatose was the only sweetener studied that did not show an association with cognitive decline.
“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.”
The authors noted several limitations. The analysis did not cover every type of artificial sweetener available. In addition, dietary information was self-reported, meaning participants may not have recalled their food and beverage intake with complete accuracy.
References:
“Association Between Consumption of Low- and No-Calorie Artificial Sweeteners and Cognitive DeclineAn 8-Year Prospective Study” by Natalia Gomes Gonçalves, Euridice Martinez-Steele, Paulo A. Lotufo, Isabela Bensenor, Alessandra C. Goulart, Sandhi Maria Barreto, Luana Giatti, Carolina Perim de Faria, Maria del Carmen Bisi Molina, Paulo Caramelli, Dirce Maria Marchioni and Claudia Kimie Suemoto, 3 September 2025, Neurology.
DOI: 10.1212/WNL.0000000000214023
“The Dark Side of Sweet: Neurocognitive Consequences of Artificial Sweeteners” by Thomas Monroe Holland, 3 September 2025, Neurology.
DOI: 10.1212/WNL.0000000000214129
The study was supported by the Brazilian Ministry of Health, the Ministry of Science, Technology, and Innovation, and the National Council for Scientific and Technological Development.
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59 Comments
Wish I could share article, not on social media but with friends
Click or tap the email icon on the share options and email it to them; or print it out from your device and share personally.
In a lot of these cases with these sweeteners it is the ultra processed foods you describe that is the problem. While erythritol has recently been pinned on the map for issues like this, xylitol allulose and monkfruit are fine.
Nice study, but i would have liked to see one group that used sugar and no artificial sweeteners.
Sugar has its own issues, but artificial sweeteners are neurotoxins.
I would like to know if it was Type 1 or Type 2 diabetes.
Sugar is fertilizer for CANCER. If you use a sweetener use stevia it’s made from natural resources. I do use Splenda in a crunch….in very small quantities. The fact is America has an Obesity problem and sugar is a huge culprit in people being overweight.
Should do research.
Should do research.
Copy the url then paste it on a notepad and save it .
Email the url to your friends
Has anyone had high glucose spikes drinking ZERO sugar soda? Im curious to see if it’s related to these sweeteners Thoughts?
I drink a ton of zero carb products. They have not spiked my blood sugar. I’ve been a type 2 diabetic for over 30 years. Before being diagnosed, I never drank them, now I drink them all the time. I keep detailed accounts of my blood sugar levels and insulin dosages. I do find that “low glycemic index” foods still spike my blood sugar levels a lot. My current A1c level is 6.8.
Pretty sure the taste of it mimicks sugar so it encourages the brain to have a sugar response
Pretty sure the taste of it mimicks sugar so it encourages the brain to have a sugar response.
Copy the webpage link and text or email it to your friends and family.
https://scitechdaily.com/popular-sugar-substitutes-linked-to-faster-cognitive-decline
Forget it, the wise don’t need it and the stupid won’t heed it.
This study is GARBAGE. Saccharine alone would bias the hell out of any test, and the fact they included that toxic old 70s relic tells me they were looking for “Artificial sweeteners BAD” rather than doing science. Sweeteners may in fact BE bad, but these studies are always propaganda. Every time I run into a anti sweetener person I casually ask them what “cra” in Sucralose stands for. Not one of them have ever bothered to looked that up, and it’s the defining attribute of that sweetener. But they still pretend to be authorities on the subject.
surprised stevia extract was not included in this study whatsoever. I like stevia extract in electrolyte drinks, and raw agave nectar syrup for teas (the latter is just low glycemic index, but still has some glucose, just lower than honey). I have always avoided anything containing aspartame-based sweeteners bc I grew up w/ my mom saying they used that in high doses in rat poison, so it’d probably be bad to regularly ingest it. also I’ve never liked sucralose since it always gave me horrible headaches, so I’ve usually avoided it. never really used Splenda/xylolitol or however it’s spelled. I am not diabetic and honestly I still have too much of high glycemic index things like I have Coca-Cola whenever I go to a restaurant or something, and I am a little bit too into chocolate-based desserts, especially when around my cycle, but I am trying to go to dark chocolate and semi-sweet instead. I don’t drink coffee, so making my own tea with agave instead of sugar is probably beneficial? I also dislike most coffee creamers so I just use whole lactose-free (I became lactose intolerant) milk in black teas. I am a pescatarian because my body hates meat and meat-based by-products for some reason, and I think that fact alone cuts out a lot of bad stuff in my diet? that all said, I am still under 30 and I don’t exercise as much as I should, and again I drink too much (regular) Coca-Cola and eat too many desserts and pastas and white rices, so it’s hard to say for sure if my avoidance of certain sweeteners is good in the long-run.
Hear hear, they include saccharine but zero mention of sucralose by far the most common current alt sweetner if you are adding it yourself ( vs aspartame in Coke Co. brand drinks which is a huge %)
Sucralose IS sugar but altered at a chemical level to prevent assimilation.
Study that.
I lost 200 pounds naturally over 3 years by using monk fruit.Don’t even start with your c*** because I would’ve been dead by now.And I feel twenty seven at age fifty seven , get the hell out of here
So I, once again, a poor study on artificial shows nothing of value. 8 years, lumping artificial sweeteners all together.
I miss the days when science writer new basic science fundamentals.
My mother lived to be 86 years old she worked up until her early seventies she started out having dementia and then full-blown Alzheimer’s and for her 25-30 years she used Sweet and low in her coffee and her tea lots of it. And she also cooked her biscuits and cornbread in aluminum pans and also made her coffee in a little aluminum coffee pot I blame her Alzheimer’s on the Sweet and low and aluminum. I have diabetes I do drink zero sugar sodas at times but I’m learning to drink mineral water with a few fresh berries in it I do use stevia excuse me not stevia but truvia in my tea and coffee.
Sorbotol is not an artificial sweetener. It is produced naturally in some fruits
Interesting, I’m sure the fact that Brazil is the world’s largest sugar cane producer and this study was supported by the Brazilian government did not, in any way, affect the outcome of this study. . .
Thanks for this information!
Bingo
Yes but in smaller concentration
Aspartame is the only one negatively affecting the brain. Don’t lump the others in. Saccharin and Splenda have no proof and the others are sourced from natural food. Cane sugar cause negative side effects though.
Aspartame is BAD NEWS, for sure!
R.
And they’re very reluctant to say so even after all the evidence supporting it.
Aspartame does not negatively impact the brain.
Why do these studies never include Stevie? It’s the only non-sugar sweetener I use (pure stevia).
I’ve used pure Stevia with inulin added (prob not allowed to say brand name) for 25+ years in my one cup of coffee/day with no ill effects that I am aware of…for a rare cup of tea I might use a tsp of local harvested honey or agave syrup, or local maple syrup. I am not diabetic, just trying to eat smart & safe, and suspicious of synthetic foods! A little cane sugar is safer IMHO. I was taught everything in moderation! I am nearly 87, had our own garden for 50+ years and ‘put food by’. What is in our grocery stores today is NOT the same!!
My thought is that stevia and monk fruit weren’t included in the study because they’re derived from actual plants. However, folks who use the findings in this study to modify their sugar substitute intake need to read the packaging very carefully. Most monkfruit products and some stevia products also contain one of the listed artificial sweeteners. Many stevia brands combine it with cane sugar or another artificial sweetener as well.
It would be useful to know more specifics about the study. There were so many artificial sweeteners studied that the article couldn’t detail the results for each.
Other than they’re being nothing wrong with it it’s just not that popular of a choice due to its mild bitter aftertaste.
Who paid for the study and was it all of them or jsut one of them?
Based on a study funded by the sugar industry? Where is are the peer reviewed references?
How do these compare to sugar consumption figures for similar cognitive effects?
How does this compare to natural sugar containing fruits and milk?
Is there a similar trend.
Has a comparable double blind test been performed.
Can the tabled data be made available for a calculation of the margin of error?
It would be interesting to perform comparative analysis on comparable studies to correlate various results, including the outliers.
Association is not causation and there could be other factors that affect the outcome of the study. Keep in mind that people generally consume artificial sweeteners because they have other existing issues like weight problems and diabetes. Sugar and other ‘natural’ sweeteners can be just as harmful when consumed in excess. The best rule of thumb for your diet is, All Things in Moderation. A serving of sugar free pudding isn’t going to hurt you. Drinking a case of diet pop daily is bad for you.
No kidding. Anytime I hear someone complain about (good) starches and artificial sweeteners it’s always followed with “I used to consume these all the time!” Like moderation wasn’t being used in the first place. Most of the time it’s a self call-out, growing up I was allowed unrestrictive access to a bowl of candy at my Grandma’s house bc they didn’t know better and I was a kid who also didn’t know better, now I’m pre-diabetic.
In the same vein. Sometimes people will try to demonize a very common and usually harmless chemical. Like poly dextrose, which is a starch that’s good for you. Or riboflavin, a very important vitamin that’s entirely necessary. My point being to anyone else reading this article or any others like this one, err on the side of caution and take what articles like this say with a grain of salt. You’re better off getting actually valid and scientifically backed information from a nutritionist, or even a gastroenterologist (basically a stomach doctor).
I could’ve already told you Aspartame is bad for you. Known about that poison since 2016-2017.
Except it’s not . There are no reasonable studies that show that. Stop being a liar
Here’s the catch. If the participants continued to have diabetes throughout the trial this means they continued a high intake of sugar to maintain that status. We really needed to see results for individuals without diabetes taking the artificial sweeteners to see how they fared. Not convinced by this study.
Interesting how the cognitive support formula NeuroDyne states on the bottle that it will improve focus, enhance memory recall, and provide mental energy but contains Xylitol & Stevia. Push me pull you situation.
what do you mean by “they continued a high intake of sugar to maintain that status?” maybe you just phrased it off, but just in case, I want to explain that type 2 diabetes affects blood sugar levels through developing insulin resistance. once you get type 2 diabetes, it doesn’t go away, you just manage it through lifestyle and/or insulin medicines. Insulin is what the body produces when the body has too high of glucose in the blood. Glucose is needed, however, for energy, but all food is broken down in the body into different forms of glucose and fatty-acid chains, which your body then uses to power all the energy it needs for your cells to function. However, refined sugar and all white breads, white pastas, white rices, and high-fructose corn syrup are all types of a shorter, simpler chemical chain than like whole wheat or or most vegetables and meats or fish. Your body breaks down these simple chains really fast, which causes your body to have bigger spikes in glucose and then really big drops afterward. Years of these extreme spikes and drops in glucose can eventually make your pancreas, which controls insulin, freak out and develop insulin resistance, and, if it’s not identified and managed, that can cause you to develop diabetes mellitus / type 2 diabetes, wherein your body produces little to no insulin anymore, so you get all this glucose that builds up in your body that isn’t being broken down, and it starts to damage your blood vessels and nerves and stuff. Alternatively, though, if you have type 2 diabetes and you just don’t eat or don’t get enough things that can be turned into glucose, your body will suffer from too low of blood sugar, and it can lead to a coma or worse. Although the latter thing can happen honestly to anyone, but is worse on people who have diabetes. Also being literally starving for a period of time makes someone more likely to develop type 2 diabetes later in life because the whole system of energy from glucose and blood glucose regulation gets thrown into haywire when a person goes through times of starvation or extreme fasting/dieting, and it can cause permanent changes to the body as it trains itself to produce less insulin just in case it faces a period of low to no energy sources again.
I am a hairdresser in Pa. Over my 30 plus years in the business and my clients that use the artificial sweetener as a replacement for sugar because of diet have died of Alzheimer’s disease and had dementia
That’s usually the result of consuming aspartame not a sugar alcohol or stevia.
Aspartame is good news! – It is two amino acids that you get in every protein source you have ever eaten. The 19 essential amino acids are, what’s the word: Essential.
Phenylalanine is used for skin pigmentation and brain neurotransmitter (what you think and remember with)
So 99.9999% of cautionary tails regarding Aspartame – are incorrect – and can only be attributed to imbeciles putting everything they hear into single, knee-jerk ideas and then start talking.
Erythritol is a Blood Thickener narrows Veins in your Body can cause Strokes & Heart attack, Splenda is Sucralose researchers found it can change your DNA ect… Safer alternatives are Monkfruit & Stevia, Do your own Investigation research…
Reverse causality. People are drawn to use artificial sweeteners because they have pre-existing health problems. Those people are prone to further future health issues and it’s not because of artificial sweeteners, but because of their poor health.
AMEN!
There is a reason that the vast majority of long term employees of the nutrasweet plant in Augusta, GA end up in skilled nursing facilities specializing in dementia and alzheimer’s care as they breathe that garbage every second they are in that plant.
He’ll likely have dementia if he continues it.
All of this stuff is dangerous. Most have Never been tested when cooked in your food. Monk Fruit is the only option that is safe and is Just Like Sugar, without the Poison.
Sugar is poison
While I am not commenting on the study itself much like the studies in the 50s and 60s, pitting fat versus sugar in the United States and finding out later that those were paid for by the sugar producers, Brazil is the number one producer and exporter of sugarcane worldwide. I wonder if there is a connection.
I lost 200 pounds naturally over 3 years by using monk fruit.
This explains why so many people watch NCIS.
More LIES from the sugar industry. I’ve been using artificial sweeteners I the amount of 8-15 cans of diet soda since age 11 due to a low metabolism. I have perfect blood numbers, I’ve had no cavities in my adult life, despite relatively minimal brushing routines with no toothpaste, no high blood pressure, incredibly low cholesterol risk (I used to eat 48 eggs a week on low carb, which raised my good cholesterol to 62 and it’s still in the high 40s twenty years later) and my IQ checks in at 140.
I’m an Electronic Engineer by trade, written rock albums (I sing a d play multiple instruments so I have no need of anyone else to make an album. I use Logic Pro. I sell it to publishers for major artists, I’ve sold award night photography photos in the 90s and I write over 32 pinball recreation simulations of real machines. My newest hobby is restoring vintage and antique lighters. My memories are sharp all the way back to the day I came home from the hospital. Save me the absolute nonsense about sweeteners!
The brain is like a muscle. If you don’t use it, you lose it! Stay busy. Learn new things, even if you have to go to school classes to do it! Build things! Repair things! Stop watching TV all the time!