Study of Low Calorie Sweeteners and the Microbiome Not Applicable to People

Calorie Control Council’s Response to the Harpaz, et al. Study

October 4, 2018 (ATLANTA) — A study recently published in the journal Molecules claimed that low- and no-calorie sweeteners (LNCS) are toxic to the gut microbiome. Using genetically-modified bioluminescent bacteria from E. coli as a sensing model, the authors sought to test the relative toxicity of six U.S. Food and Drug Administration (FDA)-approved LNCS (aspartame, sucralose, saccharin, neotame, advantame and acesulfame potassium-k (ace-k)) and that of ten LNCS-containing sports supplements and drew conclusions based on their findings. The authors suggest that the tested bioluminescent bacterial panel can potentially be used for detecting LNCS in the environment and that the study findings may aid in understanding the toxicity of these sweeteners on E. Coli, which they deem as representative of gut bacteria. The authors’ conclusions are problematic for the reasons outlined below.

Conclusions From In Vitro Study Not Applicable to Human Subjects

First, while the authors draw conclusions about the impact of LNCS on the gut microbiome, the conditions in this in vitro study are not directly comparable to the human gut. Therefore, conclusions drawn from this study cannot be extrapolated to the digestive gut microbes that are unique to humans. In addition to the notation that some of the response levels of concentration in the study exceeded the amount typically found in real food samples, the reactions seen under these conditions may not mimic what would occur under real-life exposure conditions in humans. Furthermore, although there were changes noted in the bacterium included in the study, it is unknown whether these or any changes in microbiome bacteria, are indicative of negative health outcomes in humans.

Other Ingredients Not Accounted For

Regarding the testing of the toxicity of LNCS-containing sports supplements, the inability to isolate the source of any change in the bacterium is a flaw. Given that commercially available supplements contain a number of complex ingredients, one would need to determine whether any responses seen are solely due to the sweetener and not the other ingredients. “While examining the effect of these supplements may be of interest, without this sort of isolation and in the absence of a control group, it is difficult to draw sound conclusions,” noted Dr. Ashley Roberts (pictured), a regulatory toxicologist currently working with the Calorie Control Council.

Low Calorie Sweeteners Safety Proven For Decades

Lastly, it is important to note that each of the sweeteners included in the study have undergone extensive safety assessment and have been approved for use by scientific and regulatory authorities worldwide, including the U.S. FDA, the European Food Safety Authority and the Joint FAO/WHO Expert Committee on Food Additives. LNCS are among the most studied ingredients which, in addition to their extensive history of safe use, provides a strong body of evidence in support of their safety.


Dorin Harpaz, Loo Pin Yeo, Francesca Cecchini, et al. (2018) Measuring Artificial Sweeteners Toxicity Using a Bioluminescent Bacterial Panel. Molecules 23, 2454; doi:10.3390/molecules23102454

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