A tiny worm revealed how simple sensory signals can quietly switch longevity on or off.
The idea of extending life may be especially popular among modern tech circles, but the desire to stay young or live forever has fascinated humanity for thousands of years.
Many of the most reliable strategies scientists know for increasing lifespan, including long-term dietary restriction, are difficult and often uncomfortable to sustain.
Scientists Explore a Longevity Gene
New research from the laboratory of Scott Leiser, Ph.D., in the Molecular and Integrative Physiology Department at the University of Michigan Medical School, reveals how a single longevity-related gene connects behavior, environmental signals, and biology.
These discoveries help researchers better understand the internal processes that regulate lifespan and point toward ways to extend life without relying on extreme lifestyle changes.
What Worms Can Teach Us About Aging
One study, published in PNAS, examined how environmental cues and food availability influence longevity using a tiny worm (the popular research model species, C. elegans).
“Believe it or not, most of the central ideas and types of metabolism we study are conserved from worms to people,” said Leiser.
He explained that sensing the environment triggers hormone release in humans, including adrenaline or dopamine. Worms respond in a similar way, with neurons that detect environmental changes and adjust their physiology accordingly.
Earlier studies have shown that stressful conditions such as limited access to food can improve survival.
Related work in fruit flies by Scott Pletcher, Ph.D., a colleague of Leiser at U-M, found that simply smelling food was enough to cancel out those survival benefits.
How Touch Disrupts Longevity Signals
Leiser and project leader Elizabeth Kitto, Ph.D., with support from Safa Beydoun, Ph.D., wanted to know whether other sensory experiences, such as touch, could also interfere with the lifespan extension caused by dietary restriction, and how that might happen.
To investigate, the researchers placed worms on a surface covered with beads designed to feel like the E. coli they normally encounter while feeding.
This tactile stimulation alone reduced the activity of a longevity associated gene in the intestine (fmo-2) and weakened the lifespan benefits normally produced by restricted diets.
Leiser first identified fmo-2 in 2015 as a gene that is both required and sufficient for lifespan extension triggered by dietary restriction.
“The fmo-2 enzyme remodels metabolism, and as a result increases lifespan,” he explained. “Without the enzyme, dietary restriction does not lead to a longer lifespan.”
Further experiments showed that touch activates a signaling circuit involving cells that release dopamine and tyramine. This reduces fmo-2 activity in the intestine and limits the longevity effect of dietary restriction.
Potential Implications for Human Health
According to Leiser, one of the most important takeaways is that these sensory circuits are not fixed and may be adjustable.
“If we could induce fmo-2 without taking away food, we could activate the stress response and trick your brain into making you long-lived.”
Before that becomes possible, researchers need to understand the other roles fmo-2 plays in the body.
Behavioral Side Effects of Longevity Pathways
In a second study published in Science Advances, the research team showed that altering fmo-2 also changes behavior in clear ways.
Worms engineered to produce too much fmo-2 showed little reaction to both positive and negative environmental changes. They failed to avoid potentially harmful bacteria and did not slow their eating after a brief fast, unlike normal worms.
Worms that lacked fmo-2 entirely were also affected, exploring their surroundings less often than usual. In both cases, the behavioral changes were traced to shifts in tryptophan metabolism.
“There are going to be side effects to any intervention to extend life–and we think one of the side effects will be behavioral,” said Leiser.
“By understanding this pathway, we could potentially provide supplements to offset some of these negative behavioral effects.”
Looking Ahead in Longevity Research
Leiser plans to continue studying how the brain, metabolism, behavior, and overall health interact, with the goal of helping develop future drugs that target these natural biological pathways.
“Investigating all of the individual signals that our brain is responding to from the gut is a hot but not well understood area.”
References:
“Metabolic regulation of behavior by the intestinal enzyme FMO-2” by Elizabeth S. Kitto, Safa Beydoun, Ella Henry, Megan L. Schaller, Mira Bhandari, Sarah A. Easow, Angela M. Tuckowski, Marshall B. Howington, Ajay Bhat, Aditya Sridhar, Eugene Chung, Charles R. Evans and Scott F. Leiser, 24 October 2025, Science Advances.
DOI: 10.1126/sciadv.adx3018
“Rewarding touch limits lifespan through neural to intestinal signaling” by Elizabeth S. Kitto, Safa Beydoun and Scott F. Leiser, 23 October 2025, Proceedings of the National Academy of Sciences.
DOI: 10.1073/pnas.2423780122
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4 Comments
Most humans don’t have a functioning fmo-2 enzyme. We are not worms, or fruit flies. But these researchers think humans are like worms. “If we could induce fmo-2 without taking away food, we could activate the stress response and trick your brain into making you long-lived.” Big jump from worms to humans. These studies are of no use to humanity.
Does this imply that smelling food or having sex shortens our lives? There has to be a way around this.
Don’t be silly. Of course they are.
If nothing else it reduces the number of studies that have to be conducted on humans.
You might have a hard time understanding how different species often use the same chemical processes or why that matters but it does. You can’t figure out if something will or will not work on humans from an animal study but you can find out if a substance is compatable with all sorts of chemical processes that animals share with humans to see if human studies are dangerous.
Your lack of interest in some kind of information doesn’t justify getting angry that other people consider it helpful.
Do you want anyone shutting down your thought and ideas because they think its stupid?
What’s the point? What’s the goal?
What if the behavioral effects are what drive the longevity change.