Aspartame may harm brain and heart function even at safe doses, study finds

A new study suggests that aspartame, a common artificial sweetener, could alter brain and heart function even at doses well below current safety limits. Researchers found lasting changes in mice exposed to the substance over a year, raising questions about long-term consumption.

The study tracked mice given aspartame for 12 months. Initially, their brains showed increased glucose uptake, but over time, energy levels dropped, leading to metabolic dysfunction. The sweetener also caused mild cardiac hypertrophy, weakening the heart's ability to pump blood efficiently.

Aspartame disrupted communication between neurons and astrocytes, cells that support brain function. As a result, the mice performed worse in cognitive tests. These findings challenge the idea that low doses pose no risk, even though international agencies like EFSA and JECFA have deemed it safe at up to 40 mg per kg of body weight daily.

Current safety limits were set using data from long-term rodent studies, human metabolism research, and cancer risk reviews. These showed no harm at high doses—up to 4,000 mg/kg in rodents—with large safety margins. However, the new research argues that chronic exposure, even at approved levels, may still affect energy regulation in the brain and heart.

The team behind the study now calls for a re-evaluation of aspartame's intake limits. They stress the need for closer scrutiny of its long-term effects, particularly on metabolic and cognitive heart health.

The findings suggest that aspartame's impact on brain and heart function may require further investigation. While safety agencies maintain that current limits are protective, the study highlights potential risks from prolonged exposure. This could prompt a review of how low-dose consumption is assessed in future guidelines.