Aspartame—the artificial sweetener found in everything from Diet Coke and sugar-free chewing gum to children’s medications—may raise the risk of the most common type of stroke by causing inflammation and disrupting blood vessel health and blood flow, according to new research.

Published last month [July 2025] in Scientific Reports, the study is the first to combine advanced computer modelling techniques to examine how aspartame interacts with processes in the body that can lead to a stroke or affect its severity, its authors said. The findings add to longstanding concerns about the sugar substitute’s impacts on the brain and heart.

“Given that aspartame is one of the most pervasive artificial sweeteners used in the global food industry, its cumulative effects from long-term, low-dose exposure may indirectly affect cerebrovascular [brain blood vessel] health through metabolic interference,” the researchers said.

Ischemic stroke, which accounts for about 87% of all strokes in the US and is a leading cause of death globally, occurs when a blood clot blocks a brain blood vessel, cutting off oxygen and causing brain cells to die. Common risk factors include high blood pressure, smoking, and type 2 diabetes.

Aspartame—also marketed as NutraSweet^®, Equal^®, Sugar Twin^®, and AminoSweet^®—is up to 200 times sweeter than sugar and promoted as a way to cut calories and sugar intake, especially for people with diabetes. Its safety has been debated for decades, with studies linking aspartame consumption to chronic diseases, weight gain, and even aggressive brain cancer.

This study provides preliminary systematic insights into the potential neurotoxicity mechanisms of aspartame, its authors said. They found that aspartame strongly binds to and influences five key genes that code for proteins linked to ischemic stroke. 

These proteins help regulate inflammation (the body’s response to injury or infection), blood pressure, and the strength and function of blood vessels. Disruptions may:

• Raise blood pressure
• Trigger inflammation in the brain and blood vessels
• Weaken blood vessel walls and the brain’s protective barrier (blood-brain barrier), allowing harmful substances to enter the brain and worsen a stroke

“Our integrated analysis suggests that aspartame may contribute to ischemic brain injury through multi-target interactions, potentially disrupting inflammatory responses and vascular homeostasis,” the researchers said.

Findings highlight debate over aspartame safety

Aspartame was approved in 1974 as a food additive and later as a general-purpose sweetener by the US Food and Drug Administration (FDA). A 2024 study in the Journal of Exposure Science & Environmental Epidemiology found that nearly 63% of Americans, including pregnant people and children, regularly consume products containing aspartame, which is approved in more than 90 countries.

Known as E951 in the EU, aspartame is a white synthetic powder that breaks down in the body into three byproducts: methanol, phenylalanine, and aspartic acid. The FDA maintains that aspartame is safe when consumed within the recommended daily limit of 40 milligrams per kilogram of body weight. 

However, in 2023, the International Agency for Research on Cancer (IARC) classified aspartame as “possibly carcinogenic to humans.” The World Health Organization has advised against using non-sugar sweeteners like aspartame for weight loss, citing evidence linking them to obesity, type 2 diabetes, and cardiovascular disease.

Most research into artificial sweeteners (AS) and cerebrovascular accidents (CVAs) links artificial sweetener use and strokes, especially ischemic strokes, with higher risks for female and Black populations, according to a study published last year [June 2024].

Aspartame has also been associated with weight gain and serious health problems, such as Alzheimer’s disease. In the largest study of its kind, tracking over 100,000 people for eight years, high consumption was associated with a 15% higher cancer risk. Another study suggested the artificial sweetener may alter gut bacteria in ways that promote glioblastoma, an aggressive form of brain cancer.

More information is needed to confirm the effects of aspartame on stroke risk, the researchers said. They recommended animal studies to better understand the impact of its breakdown products and long-term exposure, as well as large-scale human studies to clarify the relationship between intake levels and stroke risk.

If you are concerned about stroke risk, consider limiting your intake of aspartame and other artificial sweeteners. Choose whole, unprocessed foods, and be mindful of ingredient labels since aspartame can appear under different names, such as NutraSweet or E951.

Reference

Zhang T, Wang T, Yu K, huang C, Bao K. Aspartame and ischemic stroke: Unraveling the molecular link through network toxicology and Molecular Docking Analysis. Scientific Reports. 2025;15(1). doi:10.1038/s41598-025-08898-z