---
title: "Do artificial sweeteners speed cognitive decline?"
author: "Tess Lindqvist"
datePublished: 2026-07-18T14:43:00.000Z
canonical: "https://vitalspell.com/post/00ticg00xontb/artificial-sweeteners-cognitive-decline-study"
---

Adults who consumed the most low- and no-calorie sweeteners in a large Brazilian cohort appeared to age cognitively about 1.6 years faster than those who consumed the least, according to a 2025 [_Neurology_ study](https://doi.org/10.1212/WNL.0000000000214023) by Natália Gomes Gonçalves and colleagues. The signal was strongest in adults younger than 60 and in people with diabetes. That makes the paper easy to turn into a simple cautionary tale about diet drinks, sugar-free yogurt or packets tipped into coffee.

Yet the study itself is more complicated than that. Gonçalves and colleagues followed 12,772 adults for about eight years, tracked self-reported intake of seven sweeteners, and found that higher combined intake was associated with faster decline in verbal fluency and global cognition. But this was an observational cohort, not a randomized trial. It can show a pattern worth taking seriously. It cannot show that sweeteners, by themselves, are accelerating brain aging.

Context matters because people do not use artificial sweeteners in a vacuum. Many start after a diabetes diagnosis, during weight-loss efforts, or as part of a broader dietary shift away from sugar-sweetened drinks. The better reading of this paper is not “sweeteners are proven neurotoxic.” It is that a commonly recommended substitution may sit inside a dietary and metabolic pattern that deserves much closer scrutiny.

## What the Neurology study actually found

Inside the cohort, researchers drew on the Brazilian Longitudinal Study of Adult Health, a large middle-aged sample with repeated dietary and cognitive assessments. Participants were 51.9 years old on average at baseline, and the highest-intake group consumed about [191 mg of sweeteners per day](https://www.aan.com/PressRoom/Home/PressRelease/5281). Across follow-up, the group with the highest intake showed a 62 percent faster rate of overall cognitive decline than the lowest-intake group, a difference the authors estimated as roughly 1.6 extra years of aging in cognitive terms.

![Close-up of glass dropper and test tubes illustrating laboratory research on sweetener exposure and brain health.](https://images.pexels.com/photos/7723540/pexels-photo-7723540.jpeg?auto=compress&cs=tinysrgb&dpr=2&h=650&w=940)

Among adults under 60, the association was clearer than it was in those 60 or older, which is one reason the paper will get attention. One reading is biological: diet patterns in midlife may matter more for later cognitive trajectories than intake that begins after retirement. Another is methodological: once people are older, medication use, frailty, existing vascular disease and measurement noise make nutrition signals harder to separate cleanly.

Neither the paper nor the data pin the story on a single ingredient. Six of the seven sweeteners examined were linked to faster decline, while tagatose was not. That broad pattern argues against the tidy headline version in which one villain explains everything. It suggests either that several sweeteners share a relevant pathway, or that high sweetener use is acting as a marker for something larger in the diet or the metabolic profile of the people consuming them.

## Why the diabetes subgroup is the part to watch

Public-health relevance sits in the subgroup result, not just in the headline number. The association was stronger in people with diabetes, a population that is routinely told to reduce added sugar and often turns to low- and no-calorie sweeteners for exactly that reason.

![A glucometer surrounded by sweets, illustrating why diabetes management sits at the center of the sweetener substitution question.](https://images.pexels.com/photos/5469032/pexels-photo-5469032.jpeg?auto=compress&cs=tinysrgb&dpr=2&h=650&w=940)

Reverse causation is hard to ignore here. People with worse glycemic control, higher cardiometabolic risk or a longer history of dietary disruption may be more likely to use sweeteners heavily in the first place. In other words, the sweetener may be the exposure measured on the food questionnaire, while the harder-to-measure metabolic context is doing more of the work.

In [materials released with the study](https://www.aan.com/PressRoom/Home/PressRelease/5281), senior author [Claudia Kimie Suemoto](https://vitalspell.com/tag/claudia-kimie-suemoto) put the finding cautiously:

> “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

For readers with diabetes, two equally bad conclusions need to be avoided. The first is that sugar-free products are obviously harmless. The second is that regular sugar is therefore the safer default. This paper does not test that swap. It tests an association inside real diets, where sweetener use, diabetes burden, body weight, ultraprocessed food intake and health behavior are tangled together.

## Association is not mechanism

As signal detection, the paper is strong. As an explanation of why the signal appeared, it is much weaker. Exposure came from self-reported diet, which is standard in large cohorts but blunt. Intake can change over time. Packet counts do not fully capture sweeteners embedded in soft drinks, yogurt, protein bars or “no added sugar” packaged foods. And even sophisticated adjustment cannot erase residual confounding.

Mechanistically, the paper lands in a literature already full of competing stories. Some center insulin signaling and vascular risk. Others focus on gut microbiome shifts, altered taste conditioning, or the way highly sweet diets may sustain appetite for ultraprocessed foods. The current study does not resolve among those explanations. It mostly tells us that people who consume more of these products, especially in midlife and with diabetes, look different at the level of cognitive decline over time.

Even the authors acknowledged that limit explicitly. In a second [statement released alongside the paper](https://www.sciencedaily.com/releases/2026/07/260717033213.htm), Suemoto said more research is needed to confirm the findings and test whether other sugar substitutes may work differently.

> “More research is needed to confirm our findings and to investigate if other refined sugar alternatives… may be effective alternatives.”
>
> Claudia Kimie Suemoto

Taken literally, that is the real conclusion. A cohort study can raise the probability that a concern is real. It cannot settle the question on its own.

## The bigger story may be the dietary pattern

Context is what makes the new paper more than a one-off scare. In a 2022 [_JAMA Neurology_ paper](https://doi.org/10.1001/jamaneurol.2022.4397), Gonçalves and colleagues reported that higher ultraprocessed food consumption was associated with faster global cognitive decline in another large Brazilian sample, again with stronger effects in adults younger than 60. A separate 2022 [_Neurology_ study](https://doi.org/10.1212/WNL.0000000000200871) using UK Biobank data linked higher ultraprocessed food intake to greater risk of all-cause dementia and of Alzheimer disease and vascular dementia specifically.

Nor does that prove artificial sweeteners are just a proxy for ultraprocessed eating. It does, however, make the dietary-pattern interpretation harder to dismiss. Many low- and no-calorie sweeteners travel through the food supply inside products that are already nutritionally complicated: diet soft drinks, flavored dairy, packaged desserts, protein snacks and tabletop substitutes used in the context of calorie restriction. The brain-health question may be less about one packet in a cup of coffee than about the full pattern of products that cluster around heavy sweetener use.

For Vitalspell readers, that is the part worth carrying forward. A single observational paper should not trigger a panic about occasional aspartame or sucralose. But a large signal appearing in midlife adults, lining up with earlier processed-food and cognition work, is enough to treat high habitual use as something to watch rather than something to dismiss.

## What readers should do with this finding

Practically, the prudent take is narrow. If someone uses low- and no-calorie sweeteners heavily, especially as part of a diet already dominated by ultraprocessed foods, this paper is a reason to look harder at the total pattern. It is not a reason to assume sugar is protective. It is not proof of dementia prevention in reverse. And it is not strong enough evidence to tell people with diabetes to abandon tools they use for glucose management.

Another question is simpler: what is the sweetener replacing, and what kind of diet surrounds it? Replacing a sugar-sweetened soft drink with water is still a different move from replacing it with another ultraprocessed sweet beverage. Swapping a daily dessert for fruit is different again. Those are the comparisons brain-health research still needs to test directly.

For now, the new _Neurology_ paper lands where many nutrition papers do: not at certainty, but at a credible warning signal. The strongest version of that signal is not that artificial sweeteners have been convicted. It is that the substitution story has become harder to tell cleanly, particularly for people in midlife and for people already managing diabetes.

## References

1. Gonçalves NG, Steele EM, Lotufo PA, et al. Association Between Consumption of Low- and No-Calorie Artificial Sweeteners and Cognitive Decline: An 8-Year Prospective Study. _Neurology_. 2025;105(7):e214023. [https://doi.org/10.1212/WNL.0000000000214023](https://doi.org/10.1212/WNL.0000000000214023)
2. Gonçalves NG, Ferreira NV, Khandpur N, et al. Association Between Consumption of Ultraprocessed Foods and Cognitive Decline. _JAMA Neurology_. 2022. [https://doi.org/10.1001/jamaneurol.2022.4397](https://doi.org/10.1001/jamaneurol.2022.4397)
3. Li H, Li S, Yang H, et al. Association of Ultraprocessed Food Consumption With Risk of Dementia. _Neurology_. 2022. [https://doi.org/10.1212/WNL.0000000000200871](https://doi.org/10.1212/WNL.0000000000200871)