Sweeteners are traditionally viewed as sugar substitutes, but growing research suggests that some natural sweeteners may have broader biological effects. A 2026 study published in Food & Function found that stevioside extended lifespan and improved healthspan in Caenorhabditis elegans by activating ATFS-1 and the mitochondrial unfolded protein response (UPRmt). In an Alzheimer's disease model, stevioside also delayed paralysis, improved locomotor function, reduced ROS levels, and increased SOD activity. These findings suggest that stevioside may support healthy aging and neuroprotection through mitochondrial protein homeostasis. However, the current evidence is based on animal models, and further research is needed to determine whether these effects apply to humans.
When it comes to sweeteners, many people immediately think of sugar-free cola, zero-sugar milk tea, or ingredients in food labels whose names are difficult to pronounce. In the eyes of most consumers, sweeteners are simply alternatives to sugar—some regard them as useful tools for sugar control and weight management, while others remain cautious because of previous debates concerning their safety. Yet neither perception naturally connects sweeteners with “anti-aging.”
In recent years, however, the scientific perspective has been gradually shifting. Research has moved from an initial focus on safety evaluation toward broader investigations into metabolic regulation, gut microbiota, neuroprotection, and, most recently, the biology of aging. The research landscape surrounding certain natural sweeteners continues to expand. Researchers are beginning to recognize that the value of these compounds may go far beyond simply “replacing sugar”—they may potentially influence multiple physiological pathways and thereby exert broader effects on health.
A recent study published in 2026 even found that stevioside may activate a new mechanism closely associated with mitochondrial function, thereby extending healthspan in experimental animals and showing beneficial effects in an Alzheimer's disease model.
Latest Research on Stevioside
A 2026 study published in Food & Function revealed a new dimension of the biological functions of stevioside. Unlike previous research that has mainly focused on its classical effects, such as glucose regulation, anti-inflammatory activity, and antioxidant effects, this study was the first to establish an association between stevioside and the mitochondrial unfolded protein response (UPRmt), a mechanism that has attracted considerable attention in recent years.
Image source: PubMed
1) Stevioside Extends Healthspan
The study used Caenorhabditis elegans as a model to conduct a series of experiments. Researchers first evaluated whether stevioside could affect the lifespan of the nematodes. The results showed that stevioside extended the lifespan of C. elegans to varying degrees at concentrations of 1, 10, and 100 μmol/L.
However, the researchers did not stop at the observation of “lifespan extension.” They further evaluated healthspan, an increasingly important endpoint in aging research. Compared with the control group, stevioside-treated nematodes maintained better locomotor ability during aging. The rate at which pharyngeal pumping frequency declined was also reduced, while the accumulation of lipofuscin, a marker associated with cellular aging, was significantly decreased.
These findings indicate that stevioside not only enabled the nematodes to live longer but also delayed the decline of several physiological functions.
2) ATFS-1 Knockout Experiments
However, observing lifespan extension alone was insufficient to explain the underlying mechanism. The research team subsequently focused on the UPRmt pathway.
They measured the expression levels of the classical UPRmt markers hsp-6 and hsp-60 and found that both were significantly upregulated following stevioside treatment. At the same time, ATFS-1, a key regulatory factor of the UPRmt pathway, was also activated.
However, correlation alone was insufficient to demonstrate that UPRmt was the key mechanism through which stevioside exerted its effects. The researchers therefore conducted one of the most critical sets of experiments in the study—ATFS-1 knockout experiments.
Using ATFS-1 mutant nematodes, they repeated experiments assessing lifespan, healthspan, and oxidative stress. The results showed that once ATFS-1 was inactivated, the effects originally produced by stevioside—including lifespan extension, improved locomotor ability, and enhanced resistance to oxidative stress—were almost completely abolished.
This finding suggests that ATFS-1 was not merely involved in the process but was a key regulatory factor required for stevioside to exert these effects. It further indicates that UPRmt was not simply an accompanying phenomenon but a central component of the mechanism.
3) Stevioside Shows Neuroprotective Potential
To further explore whether stevioside might have neuroprotective potential, the research team applied it to an C. elegans model of Alzheimer's disease.
Because this model expresses human β-amyloid protein (Aβ), it gradually develops locomotor impairment and paralysis with age and is widely used to investigate pathological changes associated with Alzheimer's disease.
The experimental results showed that stevioside significantly delayed the onset of paralysis, improved locomotor ability, and enhanced the organism's resistance to oxidative stress. At the same time, reactive oxygen species (ROS) levels in the nematodes were significantly reduced, while superoxide dismutase (SOD) activity increased.
Notably, these neuroprotective effects also disappeared in ATFS-1-deficient nematodes. This further suggests that the improvement observed in the Alzheimer's disease model was not simply dependent on antioxidant activity, but was based on the restoration of mitochondrial protein homeostasis.
What Is UPRmt?
UPRmt is a self-protective mechanism that is activated when mitochondria are subjected to stress. It is also considered an important “quality-control system” for maintaining mitochondrial health.
In recent years, a growing body of research has found that UPRmt is not merely a simple stress response. It is also closely associated with aging, neurodegenerative diseases, and metabolic diseases. As aging progresses, mitochondrial quality-control capacity gradually declines, and the ability to regulate UPRmt may also become impaired. This can lead to the accumulation of abnormal proteins, reduced energy production, and greater susceptibility of cells to oxidative stress.
Therefore, rather than focusing solely on eliminating free radicals, enhancing the mitochondria's own repair capacity may be a more meaningful strategy. Moderate activation of UPRmt may help mitochondria maintain protein homeostasis and normal function, potentially coming closer to the underlying mechanisms of healthy aging than simply supplementing antioxidants.
For this reason, UPRmt has become one of the increasingly studied mechanisms in the biology of aging. Several research hotspots associated with longevity, including urolithin A (Urolithin A), regulation of nicotinamide adenine dinucleotide (NAD⁺) metabolism, and spermidine (Spermidine), have also been linked to mitochondrial quality control to varying degrees.
The Mechanism of Action of Stevioside
In the past, the health effects of stevioside have largely been attributed to antioxidant or anti-inflammatory activity. However, the research team suggests that these changes may be more likely to result from improved mitochondrial function rather than represent the starting point of the mechanism.
Based on the overall experimental findings, the authors ultimately proposed a relatively comprehensive mechanism: stevioside activates ATFS-1, thereby initiating UPRmt and promoting the expression of molecular chaperone proteins such as HSP6 and HSP60. This helps restore mitochondrial protein homeostasis and improves the mitochondria's ability to respond to stress. Subsequently, ROS accumulation is reduced and antioxidant capacity is enhanced, ultimately delaying aging, improving healthspan, and reducing neurotoxicity in the Alzheimer's disease model.
Conclusion
The above study represents an important development in research on stevioside. It is one of the relatively few studies to directly evaluate healthspan as an endpoint, while genetic experiments further demonstrated that its effects depend on the ATFS-1-mediated mitochondrial unfolded protein response (UPRmt) pathway.
This finding directly connects stevioside with a core mechanism of the biology of aging and provides a new theoretical basis for investigating its potential anti-aging and neuroprotective effects.
At the same time, it is important to emphasize that the findings described above were obtained primarily from C. elegans experimental models. Although they provide valuable insights into the biological mechanisms potentially associated with stevioside, further research, particularly in mammalian models and humans, is required to determine whether these effects can be reproduced in humans and whether they have meaningful implications for healthy aging or neurodegenerative disease.
References
-
Xiaocong Li, Yi Xiao, Fang Liu. Stevioside extends the healthspan and improves Alzheimer's disease and increases oxidative stress resistance via the mitochondrial unfolded protein response. Food & Function. (2026) 17 (11): 5021–5031.
-
Zhi Peng, Shuang Zhan, Xiulian Yang, et al. The progress on stevia (Stevia rebaudiana Bertoni): chemical composition, pharmacokinetics, pharmacological effects, safety, applications, and biosynthesis. Frontiers in Nutrition. 2026. 1728578.