New Delhi: Artificial sweeteners are widely used in sugar-free drinks and low-calorie foods, but a new study has raised questions about their potential long-term association with brain health.
Sugar-free cold drinks and other low-calorie products are often chosen as alternatives to sugary foods and beverages, particularly by people trying to reduce their sugar intake. However, new research has found an association between higher consumption of certain low- and no-calorie sweeteners and faster declines in thinking and memory abilities.
The study, published in Neurology, the medical journal of the American Academy of Neurology, followed nearly 13,000 adults for about eight years. Researchers found that participants who consumed the highest amounts of certain sweeteners experienced a faster decline in overall cognitive abilities than those with the lowest intake.
Importantly, the findings do not prove that artificial sweeteners cause cognitive decline. The study was observational and identified an association between sweetener consumption and changes in cognitive performance.
Study followed nearly 13,000 adults
Researchers from the University of São Paulo in Brazil studied 12,772 adults, whose average age was 52 years. Participants were followed for approximately eight years and were divided into three groups according to their reported consumption of low- and no-calorie sweeteners.
People in the lowest-consumption group consumed an average of around 20 milligrams of sweeteners a day, while those in the highest-consumption group consumed approximately 191 milligrams daily.
For aspartame, the consumption among people in the highest-intake group was roughly equivalent to the amount found in one can of diet soft drink.
The researchers examined seven sweeteners: aspartame, saccharin, acesulfame K, erythritol, xylitol, sorbitol and tagatose.
These ingredients are commonly found in diet soft drinks, flavoured water, energy drinks, low-calorie desserts and yoghurt. Some are also sold separately and used as alternatives to sugar in tea, coffee and cooking.
Higher intake linked to faster decline
The researchers found that participants who consumed the highest amounts of the sweeteners experienced a 62% faster decline in overall cognitive abilities compared with those in the lowest-consumption group.
The researchers estimated that this difference was comparable to approximately 1.6 additional years of cognitive ageing.
The middle-consumption group also experienced a faster decline compared with the lowest-consumption group. The researchers estimated the difference at around 35%, equivalent to approximately 1.3 additional years of cognitive ageing.
The cognitive assessments examined several areas of mental performance, including verbal fluency, working memory, word recall and processing speed.
The researchers reported that six of the seven sweeteners examined were associated with faster cognitive decline, particularly in memory.
These were aspartame, saccharin, acesulfame K, erythritol, sorbitol and xylitol.
Tagatose was the only sweetener in the study that was not associated with faster cognitive decline.
Stronger association among younger participants
The researchers found that the association appeared more pronounced among participants younger than 60.
The same pattern was not observed among participants older than 60, according to the findings.
A stronger association was also observed among people with diabetes.
Researchers noted that people with diabetes may be more likely to use sugar substitutes because they are often advised to reduce their consumption of foods and beverages that can cause blood sugar levels to rise.
This makes it difficult to determine whether the observed association is related directly to sweeteners or partly reflects other dietary and health factors among people who consume them more frequently.
Study does not establish cause and effect
Despite the findings, researchers have cautioned against interpreting the results as proof that artificial sweeteners damage the brain.
One of the major limitations of the research was that participants reported their own food and beverage consumption. Such self-reported dietary information can contain inaccuracies and may not always reflect actual intake.
The researchers also examined only seven sweeteners and did not include every low- or no-calorie sweetener currently available.
Most importantly, the study was observational.
This means researchers were able to identify a relationship between higher sweetener consumption and faster cognitive decline, but they could not establish that consuming the sweeteners directly caused the decline.
Other factors associated with dietary habits, lifestyle, metabolic health and existing medical conditions could also contribute to the observed results.
Experts call for more research
Study author Claudia Kimie Suemoto of the University of São Paulo said low- and no-calorie sweeteners are frequently viewed as healthier alternatives to sugar, but the findings suggest that some may be associated with adverse changes in brain health over time.
However, she also stressed the need for further research before firm conclusions can be drawn.
The researchers said future studies should examine the findings in greater detail and investigate whether other refined sugar alternatives could offer suitable options.
Potential alternatives mentioned by the researchers include applesauce, honey, maple syrup and coconut sugar. However, these alternatives still contain sugars or calories and should not automatically be considered healthier in every situation.
What the findings mean for consumers
The study does not mean that people who occasionally consume a sugar-free drink or use a low-calorie sweetener should assume they are at risk of cognitive decline.
Instead, the findings add to the broader scientific discussion about the long-term effects of frequently consuming artificially sweetened and ultra-processed products.
For consumers, the research highlights the importance of looking beyond whether a product is simply labelled “sugar-free” or “low-calorie”. Overall dietary quality, portion sizes and consumption patterns remain important considerations.
The study’s findings will require confirmation through further research, particularly studies capable of determining whether sweeteners themselves contribute to cognitive changes.
Until then, the research should be viewed as a warning signal for further investigation rather than proof of harm.
