A recent study conducted by researchers from Spain’s CIC biomaGUNE and the Biogipuzkoa Health Research Institute has unveiled concerning long-term health effects of the artificial sweetener aspartame. This groundbreaking research, the first of its kind to reflect real-world conditions, suggests that prolonged intake of aspartame may negatively impact brain and heart function, even at doses well below the current Acceptable Daily Intake (ADI) guidelines.
The year-long study involved exposing mice to a dosage of 7 mg/kg of body weight, approximately one-sixth of the maximum recommended daily intake. This design aimed to address key limitations seen in previous research, which often relied on shorter durations and higher dosage levels. While aspartame has been extensively studied, the findings of this research challenge existing perceptions of its long-term safety, especially considering the World Health Organization’s classification of aspartame as “possibly carcinogenic to humans” in 2023.
Researchers observed that after just two months of intermittent aspartame intake, glucose uptake in the brains of treated mice significantly increased, nearly doubling the levels seen in the control group. However, this trend reversed around the six-month mark. By the end of the study, the brains of mice consuming aspartame were utilizing approximately 50% less glucose than their counterparts. This decline indicates a potential shift from an initial state of heightened energy use to a chronic underuse, which may correlate with metabolic strain rather than adaptation.
To delve deeper into the biochemical effects, the team employed magnetic resonance spectroscopy to analyze metabolites in the cerebral cortex. Initially, levels of N-acetylaspartate (NAA), a marker for neuronal metabolism, were found to be about 13% higher in the aspartame group after two months. Yet, this initial positive outcome deteriorated, with lactate levels rising approximately 2.5 times higher in the aspartame-treated mice by the eight-month mark. Such an increase in lactate suggests cellular dysfunction and an impaired energy balance in the brain.
The study also assessed cognitive performance using the Barnes maze, a test designed to evaluate spatial learning and memory. Mice consuming aspartame exhibited slower movement and longer times in locating target escape holes compared to the control group. By the end of the study, some of the aspartame-treated mice failed to complete the task altogether, indicating a marked decline in problem-solving abilities.
In addition to cognitive impairments, the research highlighted significant changes in cardiac function among the aspartame-treated mice. Cardiac imaging revealed that their hearts were less efficient, pumping less blood with each beat despite no observable structural damage. This decrease in cardiac function could lead to reduced blood and oxygen delivery to vital organs, including the brain.
Interestingly, while aspartame-treated mice showed about 20% less total body fat than control animals over the year, this reduction did not equate to improved metabolic health. Instead, there was a concerning shift in fat distribution, with more fat accumulating around organs and less lean mass overall. This type of fat redistribution is known to exacerbate strain on the heart and metabolism.
The researchers concluded, “Aspartame does indeed reduce fat deposits (by 20%) in mice, but it does so at the cost of mild cardiac hypertrophy and decreased cognitive performance.” The findings raise important questions about the health impacts of aspartame, particularly given its widespread use since its initial approval by the FDA in 1974.
While the study’s results are based on an animal model, they underscore the necessity for long-term research to better understand the implications of chronic aspartame intake on human health. The study has been published in the journal Biomedicine & Pharmacotherapy, contributing to the ongoing discourse surrounding artificial sweeteners and their effects on health.
