Writer: Ashley Boscco
Stevia’s Secret: Unpacking the Anti-Cancer Science Behind the Green Packet
It’s 6 A.M. and, as you navigate the blur of the early morning fog and go for your essential coffee fix, you might reach for an alternative sweetener. Perhaps, today, it is the little green packet of stevia perched on the condiments tray: a simple choice to avoid refined sugars. While this small, everyday decision may feel trivial, scientists are now discovering it could have benefits other than weight-watching. In particular, recent research indicates that the natural components of the Stevia rebaudiana plant, the source of this popular sweetener, may have exploitable anti-cancer properties.
Beyond the Sweetness: Steviol Glycosides
The major players are compounds known as steviol glycosides (SGs), which give the plant leaves their natural, tooth-aching sweetness. This chemical family, theorized to act as either the plant’s natural defense or storage system, consists of a core steviol molecule linked to diverse sugar groups [1]. This conserved structure becomes critical for digestion in mammals, where the SGs are hydrolyzed by symbiotic bacteria in the colon, breaking into its two main constituents [2]. The steviol is further transported into the liver for further processing while the released sugar groups stay in the gut, unlike other sweeteners that travel to the blood. This then gives the plant extract its classification as a “sugar alternative.”
In one review, researchers compiled evidence showing that SGs counteract a variety of malignancies, from breast cancer to gastrointestinal tumors [3]. But, you may ask yourself—how can this simple compound challenge such aggressive diseases?
How it Works
Fundamentally, cancer cells are mutated host cells that ignore natural signals from the body to stop dividing or die when damaged. Steviol glycosides seem to address this issue in a few suspected ways:
Programmed Cell Death: SGs mark for cell destruction, often triggering the mitochondrial apoptosis pathway. For instance, stevioside, a common SG, was shown to increase apoptosis rate through reactive oxygen species (ROS) accumulation in breast cancer cells [3].
Cell Cycle Arrest: SGs are correlated with halting the cell cycle specifically at the G1, S, and/or G2 phases, stopping cancer cells from propagating further [3].
Inhibition of DNA Replication: Certain products such as isoteviol, made from stevioside, inhibit enzymes needed for DNA replication and stability such as mammalian DNA polymerase λ and DNA topoisomerase II [3].
Hence, through either outright destroying or stopping the replication of these cancerous cells, SGs offer a way to corral cancer’s out-of-control mechanism.
Benefits and Next Steps
While these anti-tumoral properties seem powerful, they are not unheard of in the field. Hence, what might make these molecules appealing to study? One of the major characteristics of SGs is their exceptionally low toxicity. Unlike the standard indiscriminate chemotherapy agents, SGs potentially have fewer negative effects on non-cancerous cells, suggesting a safer treatment option [3]. Furthermore, due to being sourced from a common plant, the extract is readily available for study or following large-scale drug development.
However, this does not mean we should all start switching to stevia in our morning coffees. It is critical to understand this research is still in its infancy. Most of these results come from in-vitro cell or in-vivo animal studies, needing much more rigorous clinical studies to confirm similar effects in human patients [3]. So, for now, stevia remains as a healthy sugar substitute, but its potential in cancer research reveals how even the simplest choices we make every morning may hold clues to medical breakthroughs.
References
[1] Libik-Konieczny M, Capecka E, Tuleja M, Konieczny R. Synthesis and production of steviol glycosides: recent research trends and perspectives. Appl Microbiol Biotechnol. 2021;105(10):3883-3900. doi:10.1007/s00253-021-11306-x
[2] Renwick AG, Tarka SM. Microbial hydrolysis of steviol glycosides. Food and Chemical Toxicology. 2008;46(7, Supplement):S70–S74. doi:10.1016/j.fct.2008.05.008
[3] Iatridis N, Kougioumtzi A, Vlataki K, Papadaki S, Magklara A. Anti-Cancer Properties of Stevia rebaudiana; More than a Sweetener. Molecules. 2022;27(4):1362. doi:10.3390/molecules27041362