No evidence of adverse effect of low/no calorie sweeteners on gut microbiota

ISA statement in response to new in vitro study by Markus et al.

Brussels, 8th December 2020: In response to a new in-vitro study by Markus et al.,1 the International Sweeteners Association (ISA) points to the opinions of regulatory authorities around the world which have all consistently confirmed the safety of all approved low/no calorie sweeteners, including steviol glycosides.2,3,4,5

In fact, low/no calorie sweeteners are amongst the most thoroughly researched ingredients worldwide. It goes without saying that in order to be approved for use, the regulatory authorities thoroughly assess all kinds of studies examining potential side effects, including any effect on the gut function.

Furthermore, current studies establish no evidence of any adverse effect of low/no calorie sweeteners on the gut microbiota at doses relevant to human use. Also, results of metabolism and safety studies show no evidence of a likely mechanism for a clinically relevant effect on gut microbiota.6

When looking more closely at the design of the study by Markus et al., there are several concerns. Firstly, it is important to highlight that in vitro experiments usually expose cells to high concentrations of the tested ingredient out of the human body. This means that in vitro testing conditions may cause reactions that would not be seen with real-life exposure conditions in humans. In addition, the study design ignores the well understood pathways of stevia metabolism in the gut. Thus, as also acknowledged by the authors, this study design cannot be predictive of what would happen in real-life use of steviol glycosides or any other sweetener. In fact, such studies cannot reproduce the whole, complex, interactive system that is present in an animal/ human.

At a time when obesity and non-communicable diseases including diabetes and dental diseases remain major global health challenges, and in light of current public health recommendations to reduce overall sugar intake, low/no calorie sweeteners including steviol glycosides can be helpful in creating healthier food environments. They provide a wide choice of sweet-tasting options with low or no calories, and thus can be a useful tool, when used in place of sugar and as part of a balanced diet, in helping reduce overall sugar and calorie intake.