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expert reaction to conference abstract on low-calorie sweeteners, gut bacteria and blood sugar control

The abstract for the European Association for the Study of Diabetes (EASD) annual meeting suggests that in non-diabetic subjects, low calorie sweeteners increase the amount of gut pathogens which have been linked to a deterioration in glucose regulation.


Prof Stephen Atkin, Society for Endocrinology member and Professor of Medicine, Weill Cornell Medicine Qatar, said:

“The link between low calorie sweeteners (LCS) and alteration in the gut bacteria has been shown before.  These changes in gut bacteria appear to directly affect how the body deals with sugars from food but exactly how is not known.  Changes in LCS intake changing the gut bacteria and alteration of how the body manages glucose has been reported previously.  The reduction in the hormone GLP1 that may affect how the body handles glucose is a new finding.  What is not known is if these changes are due to a specific LCS, a combination of LCSs or a general feature of all LCS.  Unfortunately from the abstract it is impossible to be more precise on how convincingly the change in GLP1 has been shown in this study.”


Dr Katarina Kos, Senior Lecturer in Diabetes and Obesity, University of Exeter, said:

“The use of artificial sweeteners and their effect on our health continues to be an intriguing topic in medical research.  Independently from this study, concerns have been raised about a potential negative impact of them on our eating behaviour by making us eat more, this by effects on the brain and some also on the microbiome.

“This latest work by Young et al which is being presented at the EASD conference is yet unpublished and thus is difficult to judge.  For now it adds to the controversy in whether sweeteners affect otherwise beneficial gut hormones known also as incretin hormones such as GLP-1 (glucagon like peptide-1) which act on insulin release from the pancreas but also on satiety/decrease in appetite.  Diabetes doctors are using treatments based on supplementing these hormones in patients with Type 2 diabetes and weight problems.

“This is thus a very important question, however no knee jerk reactions should be made and evidence of a direct causal link of sweetener use and diabetes is yet missing.

“Where does this leave us for now.  It is too early to be concerned about a potential increased risk in diabetes as result of use of artificial sweeteners and results from this study and further research is needed to validate this.  Thus guided from previous work and until we know better, we should approach sweetened drinks and food with the awareness that it may want us to ‘compensate’ with further calorie intake.  The best option for those concerned may remain water as a zero calorie drink.”


Prof Naveed Sattar, Professor of Metabolic Medicine, University of Glasgow, said:

“This study, whilst well done, is not the same as taking one or two diet drinks (containing sweeteners) per day, more often than not with food, but rather is equivalent to almost five cans of diet drinks every day for two weeks – given in the form of tablets.  Also, we don’t know what these gut marker changes really mean for health so it’s all highly speculative, and there are no clear data in humans that sweeteners alter blood sugar levels in the way that is speculated by the authors.

“Overall, therefore, this evidence will in no way stop me taking a can a day of a diet drink (or recommending such drinks as alternative to sugar rich drinks for my patients) and nor does it worry me about my diabetes risk being changed – I would much rather that than taking a drink filled full of sugar.”


Prof Kevin Murphy, Society for Endocrinology member and Professor of Endocrinology and Metabolism, Imperial College London, said:

“This is an interesting study that suggests that two weeks of dietary supplementation with low-calorie sweeteners can change the gut bacterial profile.  As the abstract doesn’t describe the magnitude or direction of all of the changes observed it isn’t easy to assess their significance.  The abstract has presumably been assessed for presentation at the conference, but the work is not published and therefore has not undergone the full peer review process.

“Previous data has shown that high levels of low-calorie sweeteners can alter the gut microbiome in mice, and changing the diet can alter the human gut microbiome within days, so the effects observed seem to fit with existing evidence.  However, while lots of interventions can change the microbiome, it is not always easy to understand the implications of these changes for human health.

“The investigators report that low-calorie sweeteners cause changes in microbial genes involved in sucrose degradation and pyruvate metabolism that appear to associate with changes in glucose metabolism.  However, while interesting, further work is needed to confirm whether this altered bacterial activity is actually responsible for the impaired glucose control observed – the work as described cannot demonstrate a causal effect.”



Abstract title: ‘Low-calorie sweeteners disrupt the gut microbiome in healthy subjects in association with impaired glycaemic control’ by R.L. Young et al.  This is a conference talk that was discussed at the European Association for the Study of Diabetes (EASD) annual meeting in Berlin. There is no paper as this is not published work.


Declared interests

Prof Stephen Atkin: “No interests.”

Dr Katarina Kos: “I have no interest to declare.”

Prof Naveed Sattar: “No COI.”

Prof Kevin Murphy: “No interests.”


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