Aspartame, an artificial sweetener approved by the US Food and Drug Administration (FDA) in 1981, is widely used in low-calorie foods and drinks. While it is found in nearly 5,000 different products consumed by adults and children, there have been question marks over potentially adverse reactions to the sweetener in some people. A 2022 study looked at the effects of aspartame on mice and suggested that it could lead to anxiety-like behavior in both mice and their offspring.
The study consisted of a sample of mice that had free access to water dosed with aspartame equivalent to 15 percent of the FDA’s recommended maximum daily amount for humans. The mice generally displayed more anxious behavior in specially designed mood tests. Anxiety was measured through a variety of maze tests on several generations of mice. The researchers also carried out RNA sequencing on key parts of their nervous systems to see how the tissue’s genes were being expressed.
The researchers found significant changes in the amygdala, a part of the brain associated with the regulation of anxiety. The effects could be seen in the animals’ offspring for up to two generations. When the mice received doses of diazepam, a drug once marketed as Valium, which is commonly used to treat anxiety in humans, anxiety-like behaviors stopped across all generations. The medication helps to regulate the same pathways in the brain that are altered by the effects of the aspartame.
While monitoring for anxiety-like behaviors in mice is merely an approximation of similar moods in humans, the researchers observed clear changes in animal behavior, which they linked to changes in gene activity. The research built on earlier work by the same team on the generational effects of nicotine consumption on mouse behavior. Something similar could be happening here, the team suggests. In other words, it’s not just those who consume the artificial sweetener who might be at risk, but also their children and their children’s children.
The team has urged caution as past research has linked artificial sweeteners to cancer, changes in the gut bacteria leading to glucose intolerance, and now anxiety. While these same results still need to be replicated in human beings, having signs of anxiety in mice is a sound reason to investigate further.
The study suggests that aspartame consumption at doses below the FDA recommended maximum daily intake may produce neurobehavioral changes in aspartame-consuming individuals and their descendants. Thus, the human population at risk of aspartame’s potential mental health effects may be larger than current expectations, which only include aspartame-consuming individuals. The research highlights the need to look back at the environmental factors because what we see today is not only what’s happening today, but what happened two generations ago and maybe even longer. While much more work needs to be done to understand what’s happening, the findings suggest that caution should be exercised when consuming aspartame.