Could the sweetened beverages we consume make us a little more anxious? A new study examines the effects of the artificial sweetener aspartame in mice suggests it’s a possibility worth exploring further.
Aspartame was approved by the US Food and Drug Administration (FDA) in 1981 and is commonly used in low-calorie foods and beverages. Today it is found in almost 5,000 different products consumed by adults and children.
When a sample of mice was given free access to water dosed with aspartame, which is 15 percent of the FDA’s recommended maximum daily intake for humans, they generally exhibited more anxious behavior in specially designed mood tests.
What is really surprising is that the effects could be observed in the offspring of the animals for up to two generations.
“What this study shows is that we need to look back at the environmental factors because what we are seeing today is not only what is happening today, but also what happened two generations ago and maybe even longer.” says neuroscientist Pradeep Bhidefrom Florida State University in the USA.
Anxiety was measured by a variety of maze tests in several generations of mice. The researchers also performed RNA sequencing on key parts of their nervous system to determine how the tissue’s genes were expressed. The researchers found significant changes in the amygdala, a part of the brain linked to the regulation of anxiety.
We know that when aspartame is consumed, it breaks down into aspartic acid, phenylalanine and methanol, all of which belong together affect the central nervous system. There are already been a question mark about potentially adverse reactions to the artificial sweetener in some people.
When the mice were given doses of diazepam — a drug once marketed as Valium and commonly used to treat anxiety in humans — fear-like behaviors across generations stopped. The drug helps regulate the same pathways in the brain that are altered by the effects of aspartame.
Although monitoring for fear-like behavior in mice is only an approximation of similar moods in humans, the researchers observed marked changes in the animals’ behavior that they linked to changes in gene activity.
“It was such a robust, fear-like trait that I don’t think any of us expected to see it.” says Sara Jones, a research assistant at Florida State University. “It was totally unexpected. Usually you see subtle changes.”
The research follows previous work by the same team on the generational effects of nicotine consumption on the behavior of mice: these effects can also be passed on through generations, apparently due to non-coding epigenetic Changes in the genes of mouse sperm cells.
Something similar could happen here, the team suggests. Not only those who consume the artificial sweetener are at risk, but also their children and grandchildren. How that might happen is not yet fully understood, but fits with new evidence pointing to epigenetic marks can remain intact over numerous generations.
researchers have looked at the links between aspartame and fear, and although plausible, other animal studies have found no change in anxiety-like behavior in rats given artificial sweeteners, suggesting that much more work needs to be done to understand what is happening.
Nonetheless, based on these results, Jones, Bhide and colleagues advise caution. Previous research has linked artificial sweeteners against cancerand Changes in gut bacteria leading to glucose intolerance; Fear is perhaps another thing to consider now.
While the same findings have yet to be replicated in humans, signs of anxiety in mice are a good reason to investigate further.
“Extrapolation of the results to humans suggests that consumption of aspartame at doses below the FDA recommended maximum daily dose may induce neurobehavioral changes in aspartame consuming individuals and their offspring,” the researchers write in their published paper.
“Therefore, the human population at risk from the potential mental health effects of aspartame may be larger than current expectations, which include only individuals who consume aspartame.”
The research was published in PNAS.
