Could the sugary drinks we spill make us a little more anxious? A 2022 study that looked at the effects of artificial sweetener aspartame in mice suggested that this is a possibility worth further investigation.
Approved by the United States Food and Drug Administration (FDA) in 1981, aspartame is widely used in low calorie foods and beverages. Today, it is found in nearly 5,000 different products consumed by adults and children.
When a sample of mice had free access to water dosed with aspartame equivalent to 15% of the FDA’s maximum daily recommended amount for humans, they generally displayed more anxious behavior on specially designed mood tests.
What is really surprising is that the effects could be observed in the offspring of the animals, up to two generations.
“What this study shows is that we need to look back at environmental factors, because what we see today is not just what is happening today, but what happened a long time ago. two generations and maybe even longer,” said Pradeep Bhide, a neuroscientist at Florida State University. said in a 2022 statement.
Anxiety was measured by a variety of maze tests over several generations of mice. The researchers also performed RNA sequencing on key parts of their nervous system to determine how tissue genes were expressed.
The researchers found significant changes in the amygdala, a part of the brain associated with anxiety regulation.
We know that when consumed, aspartame breaks down into aspartic acid, phenylalanine and methanol, all of which can affect the central nervous system. There is already been question marks about potentially adverse reactions to the sweetener in some people.
When the mice were given doses of diazepam – a drug formerly marketed as Valium, which is commonly used to treat anxiety in humans – anxious behaviors stopped across generations. The drug helps regulate the same pathways in the brain that are impaired by the effects of aspartame.
Although monitoring anxious behaviors in mice is only an approximation of similar moods in humans, the researchers observed clear changes in animal behavior, which they linked to changes in the activity of Genoa.
“It was such a robust anxiety trait that I don’t think any of us expected us to see it,” Said Sara Jones, a graduate research assistant at Florida State University. “It was completely unexpected. Usually you see subtle changes.”
Research based on Previous work by the same team on the generational effects of nicotine consumption on the behavior of mice. Again, these effects can apparently be passed down from generation to generation due to non-coding epigenetics changes in mouse sperm genes.
Something similar could happen here, the team suggests. In other words, it’s not just those who consume the artificial sweetener who could be at risk, but also their children and their children’s grandchildren.
How this might happen is not yet fully understood, but matches emerging evidence that suggests epigenetic marks can indeed remain intact through many generations.
The researchers have take into account the links between aspartame and anxiety before, and although plausible, other animal studies have found no change in anxious behavior in rats given artificial sweeteners, suggesting that a lot more work needs to be done to figure out what’s going on.
Even so, based on these results, Jones, Bhide and their colleagues urged caution. Previous research has linked artificial sweeteners against cancerAnd changes in gut bacteria leading to glucose intolerance; anxiety is now perhaps another thing to consider.
While these same results have yet to be replicated in humans, having mice show signs of anxiety is a good reason to investigate further.
“Extrapolation of the results to humans suggests that consumption of aspartame at doses below the FDA’s recommended maximum daily intake may produce neurobehavioral changes in aspartame-consuming individuals and their descendants,” the authors wrote. researchers in their report. paper 2022.
“Thus, the human population at risk for the potential mental health effects of aspartame may be larger than current expectations, which only include people consuming aspartame.”
The research has been published in PNAS.
A version of this article was first published in December 2022.