Assessing the in vivo data on low/no-calorie sweeteners and the gut microbiota

Author(s): Lobach AR, Roberts A, Rowland IR
Publication name: Food and Chemical Toxicology (2019), doi:
Publication year: 2018


Low/no-calorie sweeteners (LNCS) are continually under the spotlight in terms of their safety and benefits; in 2014 a study was published linking LNCS to an enhanced risk of glucose intolerance through modulation of the gut microbiota. In response, an in-depth review of the literature was undertaken to evaluate the major contributors to potential changes in the gut microbiota and their corresponding sequelae, and to determine if consuming LNCS (e.g., acesulfame K, aspartame, cyclamate, neotame, saccharin, sucralose, steviol glycosides) contributes to changes in the microbiome based on the data reported in human and animal studies. A few rodent studies with saccharin have reported changes in the gut microbiome, but primarily at high doses that bear no relevance to human consumption. This and other studies suggesting an effect of LNCS on the gut microbiota were found to show no evidence of an actual adverse effect on human health. The sum of the data provides clear evidence that changes in the diet unrelated to LNCS consumption are likely the major determinants of change in gut microbiota numbers and phyla, confirming the viewpoint supported by all the major international food safety and health regulatory authorities that LNCS are safe at currently approved levels.


This extensive review of the scientific literature concluded that current studies investigating the impact of low calorie sweeteners on gut microbiota show no evidence of any adverse effect on the gut microbiota at doses of low calorie sweeteners relevant to human consumption. Results of metabolism and safety studies show no evidence of a likely mechanism for a clinically relevant effect of low calorie sweeteners on gut microbiota.

The authors note that the reports of correlated effects primarily stem from animal studies where doses employed are beyond the possible expected intakes of humans, where there existed significant study design issues that make conclusions of effects questionable, or where data were incorrectly evaluated/ interpreted. Future studies evaluating the impact of food additive/ ingredient consumption on the gut microbiota need to be conducted in relevant animal models or clinical populations at relevant exposure levels and be carefully controlled to account for the presence of numerous confounding factors, including the habitual or background diet.

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