The natural sweetener stevia may disrupt communications among gut bacteria, leading to health issues, a team of researchers at Ben-Gurion University of the Negev have discovered.
Scientists examined the effect of the popular sugar substitute and its purified extracts and found that while it did not destroy bacteria it did inhibit their communication pathways. In higher concentrations, it also led to an imbalance of the gut microbiome, the microorganisms that live in the digestive tracts of humans and other animals.
The research was recently published in the scientific journal Molecules.
While the initial findings are concerning, Dr. Karina Golberg, the lead researcher of the study from BGU’s department of biotechnology engineering, cautioned that additional experiments are needed to give conclusive results.
“Regarding safety, [at] this stage of the study we cannot say that stevia is toxic or not safe, and further in vivo studies are required,” Golberg told The Media Line, noting that the experiments were conducted in a lab setting and not on animals or humans.
“We’re not coming to say that ‘you are forbidden from taking stevia because there is a health implication,’” she stressed. “However, [those] taking stevia need to take into consideration that we can actually harm the microbiome by affecting its communication system.”
Golberg added that scientists also are still unsure of the overall health implications of such disruptions and how they would translate into health issues.
Earlier studies carried out by Ben-Gurion University in 2018 showed that artificial sweeteners such as aspartame or sucralose were toxic to the bacteria found in the digestive system and could cause a wide range of serious health problems from weight gain to diabetes, and even cancer.
Unlike its artificial counterparts, however, stevia is natural. Derived from a plant that is native to South America, for centuries indigenous groups have used stevia in local teas and medicines. It was first introduced to the US market in 2008 and to Israel in 2012.
“We showed that even a natural supplement can actually disrupt bacterial communication,” Golberg said.
The biological communication process between cells is known as quorum sensing. Several species of gut bacteria rely on it for a variety of functions, including synchronizing their activity or monitoring their environment.
“Bacteria are talking with a chemical language,” said Prof. Ariel Kushmaro of the department of biotechnology engineering at BGU, who supervised the study.
“What we saw in our research is that these [stevia] molecules are actually interfering with this communication and they can specifically bind to receptors that are related to this communication,” he said.
Nevertheless, he also cautioned against jumping to conclusions about the effects of stevia.
“It could be that in the human gut it will behave a bit differently,” he said. “I would not state it firmly, but we can consider that a high concentration of stevia long-term … I’m not sure if it would be good for us.”
As an alternative to sugar, stevia has grown in popularity in recent years in the food industry, amid rising obesity and diabetes rates and as more and more people attempt to reduce their sugar intake. It is about 100-to-300 times sweeter than regular table sugar but has no calories or carbohydrates.
The popular sweet leaf has replaced aspartame and other artificial sweeteners in everything from soft drinks and baked goods, to candy and chocolate milk. According to market analyst Emergen Research, the global stevia market is expected to reach nearly $1.2 billion by 2027.
In addition to Golberg and Kushmaro, the BGU research team included Prof. Robert Marks, students Orr Share of BGU and Victor Markus of Near East University in Cyprus, Prof. Kerem Terali from Near East University and Prof. Nazmi Ozer from Hacettepe University in Cyprus.
The next stage of the research will be conducted on animals, most likely mice, to see if stevia displays the same worrying effects as those observed in the lab.