Aspartame, an artificial sweetener commonly found in diet drinks and food, may raise the risk for anxiety, early research suggests.

In a new preclinical study, investigators observed that mice that drank water containing aspartame exhibited pronounced anxiety-like behaviors in a variety of maze tests.

This behavior occurred at aspartame doses equivalent to less than 15% of the maximum daily human intake recommended by the US Food and Drug Administration (FDA).

“It was such a robust anxiety-like trait that I don’t think any of us were anticipating we would see. It was completely unexpected. Usually you see subtle changes,” lead author Sara Jones, doctoral candidate at Florida State University (FSU) College of Medicine, in Tallahassee, said in a news release.

Transgenerational Transmission

When consumed, aspartame becomes aspartic acid, phenylalanine, and methanol ― all of which can have potent effects on the central nervous system.

Exposing the mice to aspartame also produced changes in the expression of genes regulating excitation-inhibition balance in the amygdala, a brain region that regulates anxiety and fear.

“Extrapolation of the findings to humans suggests that aspartame consumption at doses below the FDA recommended maximum daily intake may produce neurobehavioral changes in aspartame-consuming individuals and their descendants,” they write.

“Thus, human population at risk of aspartame’s potential mental health effects may be larger than current expectations, which only include aspartame-consuming individuals,” they add.

Far From Harmless?

The investigators plan to publish additional data from the study that focus on how aspartame affected memory in the mice.

In future research, they hope to identify molecular mechanisms that influence the transmission of aspartame’s effect across generations.

The FSU study joins several others that discount the long-held notion that aspartame and other nonnutritive sweeteners have no effect on the body.

As reported by Medscape Medical News, in a recent study researchers found that these sugar substitutes are not metabolically inert and can alter the gut microbiome in a way that can influence blood glucose levels.

Artificial sweeteners have also been linked to an increased risk for heart disease and stroke and for cancer.