Non-nutritive sweeteners and human glucose tolerance: is stevia an exception?

While generalised research suggests that non-nutritive sweetener may impair glycaemic responses, stevia specialists are finding that this hypothesis may be flawed when it comes to the effects of stevia rebaudiana.

Stevia is an exceptional weight-loss tool, with repeated studies suggesting that it provides a sustainable, healthy and low-glucose alternative to current processed diets. In academic studies however, it can sometimes be erroneously grouped with other non-nutritive sweeteners (NSS) such as aspartame or saccharine, which leads to researchers concluding that NSS in general do not provide a healthy alternative to traditional free sugars, and by extension, unfairly tarring stevia with the same brush.

The study Personalized microbiome-driven effects of non-nutritive sweeteners on human glucose tolerance, a recently published study in Cell Scientific, by Suez et al., examined various sweeteners and their effects on blood-glucose levels. The study did not regard stevia as a tool to combat both high levels of blood sugar, and the global obesity crisis (which are intrinsically linked through processed diets), despite a significant number of studies suggesting otherwise.

It can be suggested here that the aim of the study is to promote innovative solutions related to personalized nutrition, rather than practical ones, and by minimising the impact of stevia (alongside all the other major benefits in moving away from modern high-sugar diets) they are intentionally misleading readers to improve the perception of their product, while reducing perceptions of stevia.

It is possible that as the researchers appear to have approached this study with the aim of promoting their own personalised nutritional ventures, they have unintentionally biased the results of the work. The desire to define a top respondent (a participant who responded negatively to stevia) to demonstrate the effects of NSS may have been affected by their pre-exposure to microbiome heterogenicity.  While an interesting approach for personalized nutrition, the statistical significance of its results, essentially segregated, remains unclear.

So, if the Suez study does not really look at the benefits of stevia usage, what evidence is available to support the claim that stevia is a highly beneficial?

Let us instead consider the wealth of information that suggests stevia is a long-term solution to obesity and gut health. A 2019 joint study conducted by Liverpool Hope and Bern Universities has found that stevia does not result in a raise in postprandial glucose levels. The study goes on to suggest that these findings mean that stevia has a role to play in combatting global obesity levels thanks to the fact that unlike many other NSS, it acts as an appetite suppressant (Farhat, Berset & Moore, 2019) – meaning that the use of stevia in food production is likely to encourage lower overall levels of consumption – resulting in not only good health outcomes, but environmental ones too.

This is in line with findings in a separate 2020 study (reference), found that there was little difference between the blood-glucose levels in participants who consumed stevia, and those who did not eat at all – suggesting again that stevia was not directly responsible for the glucose tolerance issues suggested in Cell (Ajami et al., 2020). This particularly study, which took place in Iran, worked primarily with diabetics, demonstrating that for glucose-sensitive groups, such as diabetics, stevia results in a safe and effective form of glucose control.

 Equally, a 2021 study into the potential risks of stevia claimed that claimed that “Groups of diabetic mice that consumed the antioxidant fraction of Stevia supplements showed better glucose tolerance than the control group” and that “Stevia leaf extract was found to be able to inhibit α-amylase and α-glucosidase. This can potentially slow down carbohydrate metabolism and reduce the risk of hyperglycemia in patients with type 1 and type 2 diabetes (Ruiz-Ruiz et al., 2015).” (Peteliuk et al., 2021)

Critically (and in direct contrast to Suez), the study also noted that “some studies on humans found no effects of supplements of Stevia aqueous extract on glucose, insulin, and glycosylated hemoglobin levels, but also no side effects (Barriocanal et al., 2008; Ajami et al., 2020).” – suggesting that the rise in blood-glucose levels in Suez are overstated, potentially as a result of the study serving as a platform for the DayTwo startup.

Once again, the environmental benefits of stevia are also notably absent from the original Suez study. Stevia uses less water, significantly less land and can be refined through a 100% water-based system, meaning that a switch to stevia not only benefits the consumer, but also the planet as a whole – something not seen in other sweeteners.

It seems that the wealth of stevia-based research that exists largely agrees that stevia does not lead to significant glycaemic alteration (especially when compared to saccharine and sucralose, two of the most popular sugar alternatives) – and that studies which suggest that this is not the case are outliers. When it comes to healthy sweetness, there is little in the world that has as much potential to benefit waistlines as stevia.




Ajami M, Seyfi M, Hosseini FAP, Naseri P, Velayati A, Mahmoudnia F, et al. Effects of Stevia on glycemic and lipid profile of type 2 diabetic patients: A randomized controlled trial. Avicenna J Phytomed. 2020;10:118–27.

Barriocanal LA, Palacios M, Benitez G, Benitez S, Jimenez JT, Jimenez N, et al. Apparent lack of pharmacological effect of steviol glycosides used as sweeteners in humans. A pilot study of repeated exposures in some normotensive and hypotensive individuals and in Type 1 and Type 2 diabetics. Regul Toxicol Pharmacol. 2008;51(1):37–41.

Farhat G, Berset V, Moore L. Effects of Stevia Extract on Postprandial Glucose Response, Satiety and Energy Intake: A Three-Arm Crossover Trial. Nutrients. 2019 Dec 12;11(12):3036. doi: 10.3390/nu11123036. PMID: 31842388; PMCID: PMC6950708.

Peteliuk V, Rybchuk L, Bayliak M, Storey KB, Lushchak O. Natural sweetener Stevia rebaudiana: Functionalities, health benefits and potential risks. EXCLI J. 2021 Sep 22;20:1412-1430. doi: 10.17179/excli2021-4211. PMID: 34803554; PMCID: PMC8600158.

Ruiz-Ruiz JC, Moguel-Ordoñez YB, Matus-Basto AJ, Segura-Campos MR. Antidiabetic and antioxidant activity of Stevia rebaudiana extracts (Var. Morita) and their incorporation into a potential functional bread. J Food Sci Technol. 2015;52:7894–903.