A widely used artificial sweetener, aspartame, commonly found in diet beverages, chewing gum, and low-sugar yogurts, may elevate insulin levels, potentially increasing the risk of heart disease, according to a new study.
Researchers from the Karolinska Institute in Sweden and Shandong University in China conducted experiments on mice to investigate the metabolic effects of aspartame. The study, published in *Cell Metabolism*, revealed that mice consuming aspartame exhibited significant increases in insulin levels within 30 minutes of intake. This insulin surge was associated with the development of larger, lipid-rich plaques in their arteries, a condition known as atherosclerosis, which heightens the risk of heart attacks and strokes.
The lead researcher, Yihai Cao, emphasized the pervasive presence of artificial sweeteners in modern diets, stating, “Artificial sweeteners have penetrated almost all kinds of food, so we have to know the long-term health impact.” The study suggests that aspartame’s intense sweetness—approximately 200 times that of sugar—may deceive the body’s sweet-sensing receptors, leading to excessive insulin release.
In the experiments, mice were administered a daily dose of aspartame equating to the human consumption of about three cans of diet soda. Over a 12-week period, these mice developed more pronounced atherosclerotic plaques compared to those that did not consume the sweetener. The researchers identified the immune signaling molecule CX3CL1 as a key player in this process. Elevated insulin levels appeared to increase CX3CL1 production, which in turn attracted inflammatory immune cells to the arterial walls, promoting plaque formation. Notably, when the CX3CL1 receptor was genetically removed from the mice, the adverse effects of aspartame on arterial health were mitigated.
While these findings in animal models raise concerns, experts caution against directly extrapolating the results to humans. Professor Naveed Sattar, a specialist in cardiometabolic medicine at the University of Glasgow, noted, “The study is interesting but has limitations. The mice used were genetically predisposed to develop atherosclerosis, and the doses of aspartame were relatively high. More research is needed to determine if these effects occur in humans at typical consumption levels.”
Aspartame has been a subject of debate regarding its safety. In July 2023, the International Agency for Research on Cancer , a branch of the World Health Organization , classified aspartame as “possibly carcinogenic to humans” based on limited evidence linking it to liver cancer. However, concurrent evaluations by the WHO and the Food and Agriculture Organization maintained that aspartame is safe for consumption within established daily intake limits.
Regulatory agencies, including the U.S. Food and Drug Administration and the European Food Safety Authority , have consistently deemed aspartame safe when consumed within recommended guidelines. The FDA stated, “Aspartame is one of the most studied food additives in the human food supply. FDA scientists do not have safety concerns when aspartame is used under the approved conditions.”
Despite regulatory assurances, the new findings contribute to a growing body of research suggesting potential metabolic effects of artificial sweeteners. Previous studies have indicated that artificial sweeteners may influence insulin resistance and glucose metabolism. For instance, research published in the *Journal of the International Society of Sports Nutrition* found that aspartame, when consumed with carbohydrates, significantly lowered insulin levels during exercise compared to carbohydrates alone.
Given the widespread use of aspartame and other artificial sweeteners, understanding their long-term health impacts remains crucial. The current study’s authors advocate for further research to explore the effects of aspartame on human metabolism and cardiovascular health. They also suggest investigating whether reducing aspartame intake could benefit individuals with metabolic disorders.
In the interim, health professionals recommend moderation. Dr. Cao advises, “While occasional consumption of products containing aspartame is unlikely to cause harm, individuals should be mindful of their overall intake, especially if they have existing health conditions such as diabetes or heart disease.”
