An association between the artificial sweetener aspartame and anxiety-like behaviour in rats was discovered by researchers at Florida State University College of Medicine in a recent study.
The peer-reviewed study discovered that even aspartame that complies with FDA limits can trigger anxiety. It was published earlier this month in the Proceedings of the National Academy of Sciences.
The scientists discovered that aspartame, when consumed, degrades into aspartic acid, phenylalanine, and methanol. These three substances can all have significant effects on the central nervous system.
The aspartame concentration in the mice's drinking water during the trial, which was overseen by PhD candidate Sara Jones, was around 15% of the FDA-approved daily maximum for humans.
For comparison, the dosage is equivalent to eight-ounce cans of diet Coke used daily by humans. The trial ran for 12 weeks over a period of four years.
The scientists discovered rising levels of anxiousness in the mice over time. Additionally, they observed alterations in the mice's gene cells. After receiving aspartame, the mice's amygdala, a region of the brain that regulates emotions and fear reactions, activated more frequently than usual. The mice's greater anxiousness may be explained by this fact.
"It was such a robust anxiety-like trait that I don't think any of us were anticipating we would see," Health News quoted Jones as saying. "It was completely unexpected. Usually, you see subtle changes."
What was perhaps more shocking was that the male offspring who had been exposed to aspartame had higher anxiety levels.
Genetic research, however, also revealed that the aspartame-induced changes in the amygdala were passed down to the children of the mice that were administered the sweetener, but not to the generation after them.
Pradeep Bhide, who holds the Jim and Betty Ann Rodgers Eminent Scholar Chair of Developmental Neuroscience in the Department of Biomedical Sciences, explained:
This study's findings suggest that in order to understand what is happening today, we must first consider what was happening two generations ago and possibly even earlier.
The aspartame-exposed mice were given diazepam, popularly known as Valium, to make them feel less anxious. How diazepam affected the aspartame-exposed mice in regard to their progeny was a significant study finding.
Diazepam was far more effective at reducing anxiety in the mice's progeny than aspartame did when it was administered to the aspartame-exposed animals. This shows that the effects of the sweetener fade over time.
Aspartame is a tabletop sweetener that is also utilised in prepared foods, beverages, and low-heat recipes. It has been linked in studies to conditions such as brain tumours, Parkinson's disease, Alzheimer's, and multiple sclerosis.