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Researchers presented an unpublished abstract on the association between artificial sweeteners and type 2 diabetes at the European Association for the Study of Diabetes.
Prof. Victor Zammit, Professor of Metabolic Biochemistry, University of Warwick, said:
“Although an exaggerated response to glucose intake after a meal could mimic the harmful effects of poor glucose control in diabetes, it is not possible, from the data presented, to interpret this as necessarily indicating that such increased responses will result in the development of type-2 diabetes itself, until we know the extent of the damage that such increased, sweetener-induced glucose excursions actually cause. Therefore the claim that sweeteners may cause (as opposed to be associated with) type-2 diabetes would have to wait until proper clinical trials are performed, as increased sweetener intake may be associated with other lifestyle elements that may be more direct causes of type-2 diabetes.”
Dr Ines Cebola, Research Associate, Imperial College London & member of the Society for Endocrinology, said:
“This study addresses a very important global human health issue, as artificial sweeteners are food additives commonly used not only by patients with diabetes, but also by healthy individuals aiming to manage their sugar intake.
“Although generally thought as safe and even beneficial, artificial sweetener consumption has actually been previously associated with weight gain and development of glucose intolerance, which can lead to development of type 2 diabetes (T2D). However, the controlled studies performed so far to address the consequences of artificial sweetener consumption were mainly performed in mice – a gap that the study from Richard Young and colleagues tries to fill.
“Even though the study is limited in power by the reduced number of individuals, it is quite striking to observe marked differences in glucose response in individuals taking the artificial sweetener supplementation for only two weeks. It would be interesting to further investigate the underlying mechanisms of these observations.
“As with any study of this nature, replication of the observations in a different and larger group of individuals is key to fully grasp their meaning and implications for the broader population. Even if it is proven in the future that artificial sweeteners are detrimental for the general population, this might not be true in all cases. Type 2 diabetes arises from an interaction between environmental and genetic factors, many of which we do not fully understand yet. It is thus premature to point the finger at artificial sweeteners as isolated elements of risk. The full story will probably prove itself a lot more complex.Thus at the moment, I would not advise against artificial sweeteners per se, but instead I would stress the importance of a balanced diet and regular exercise.”
Dr Ian Johnson, Nutrition researcher and Emeritus Fellow, Quadram Institute Bioscience, said:
“This relatively small, un-published study reports a change in the normal physiological response to carbohydrate entering the intestine in healthy volunteers who have previously consumed artificial sweeteners for a prolonged period. The apparent increase in the rate of glucose absorption is certainly interesting, and adds to previous data suggesting that artificial sweeteners are not metabolically inert. However, the mechanism remains poorly defined, and the findings do not necessarily imply any increased risk of type 2 diabetes in healthy individuals. These results suggest a need for further research, but in my opinion any suggestion of a direct link to the development of disease remains speculative at this stage.”
Prof. Nick Finer, Honorary Clinical Professor, National Centre for Cardiovascular Prevention and Outcomes, UCL, said:
“This research, so far details of which are only available in un-published abstract form, explores the impact of supplements of the commonly used non-caloric artificial sweeteners sucralose and acesulfame-K on glucose absorption from the gut. Non-caloric sweeteners have been much researched over the past twenty years with contradictory findings about their potential for benefit or harm. Recent research has shown that there are sweetness receptors in the gut that may signal locally to release hormones that increase insulin secretion, glucose absorption and signalling to the brain to affect hunger and reward sensations.
“This research in human volunteers showed that after two weeks of non-caloric sweetener supplement (equivalent to about 1.5 litres of a diet soda daily) impaired the way in which a glucose load delivered into the duodenum (the part of the gut past the stomach) was handled resulting in higher blood glucose levels similar to those seen in people developing type 2 diabetes. While this was very much an experimental study (for example, the glucose was delivered directly into the duodenum through a tube inserted by endoscopy), it does suggest that the effects of sweeteners may be far more complex than once thought; their speculation that sweeteners such as these could lead to diabetes seems a conclusion too far.”
Dr Abd Tahrani, NIHR Clinician Scientist, Institute of Metabolism and Systems Research, University of Birmingham, & Honorary Consultant Physician in Diabetes and Endocrinology, Birmingham Heartlands Hospital, said:
“The research quality and the design of the study are strong. However, the extrapolation of the results is beyond the findings of the study. The study was performed in healthy lean individuals and hence the results may not necessarily apply to those who develop Type 2 diabetes, who are usually obese. An important issue that the abstract does not mention is whether the study population were at increased risk of diabetes (such as family history). As a result, making conclusions regarding how artificial sweeteners increase the risk of Type 2 diabetes in individuals who are not at increased risk of the disease when the disease usually occurs in patients who have multiple risk factors, is inaccurate. Furthermore, this study is relatively of short duration, and how the dynamics of glucose handling are affected by longer more chronic use cannot be concluded based on the current study.
“Previous cohort studies showed that the consumption of artificial sweeteners was associated with increased weight and increased risk of Type 2 diabetes and cardiovascular disease risk factors (http://www.cmaj.ca/content/189/28/E929 ). Randomised controlled trials did not show particular benefits of artificial sweeteners. However, overall the literature is not consistent regarding whether artificial sweeteners have beneficial or harmful effects (https://www.ncbi.nlm.nih.gov/pubmed/28886707 ). This, in part, reflects variation in study populations.
“As far as I can see there is no accounting of any changes in dietary habits or physical activity over the trial period. More importantly, the study population is healthy lean and the trial duration is 2 weeks and the amount of artificial sweeteners is 1.5 L/day; hence the results cannot be generalised to other populations.
“The results of the study are thought provoking and quite interesting but the implications on the real world are rather limited at this stage although further research will no doubt be needed and interesting. In simple terms, the results are saying that in people who are healthy and lean and consume 1.5 L a day of diet soda, then glucose metabolism might get disturbed. The conclusion of the abstract is valid but this statement at the end “This study supports the concept that NAS have a deleterious impact on acute glycaemic control, and highlights the potential for exaggerated postprandial glycaemic excursions in high habitual NAS consumers, which could predispose to T2DM” is an over-speculation.
“It is too early to decide whether diabetics or those at risk of diabetes should avoid artificial sweeteners, because we do not know the impact of using artificial sweeteners when combined with life style intervention, limited carbohydrate intake or using weight loss pharmacotherapy. However, the results are very interesting and certainly will lead to several future studies. Patients with diabetes or at increased risk of diabetes should follow a healthier life style which has been shown in multiple trials to reduce the risk of developing type 2 diabetes and improve glycaemic control in those with diabetes.”
Further background information from Prof. Victor Zammit:
“Reducing caloric intake is a central plank of lifestyle changes that we are encouraged to adopt to reduce the risk of obesity and its associated metabolic disorders, including type-2 diabetes and heart disease. Therefore, the use of artificial sweeteners in fizzy drinks (which are consumed in large quantities by communities in the industrialised world) seems to make eminent sense. In addition to reducing the number of calories we ingest (in N. America, calories associated with fizzy drink intake can account for up to 18% of total daily intake for individuals), the use of artificial sweeteners specifically reduces the amount of fructose within the sucrose (sugar) molecule that is ingested. Fructose has many harmful effects, including the stimulation of fat synthesis by the liver, and the excessive formation of uric acid which, besides raising the risk of gout, also has direct pro-inflammatory effects on the cardiovascular system.
“The relatively recent discovery that ‘sweet’ receptors are not just present in our mouths, but also deep in our intestinal system has raised the prospects that artificial sweeteners might ‘signal’ through these receptors to alter the hormonal responses of the gut itself to food intake. In particular, because we tend to drink sweetened drinks with our meals (which will contain glucose and glucose-generating carbohydrates), the possibility arises that artificial sweeteners could alter the way that the gut processes glucose itself. The study by Young et al shows that this does indeed happen. Stimulation of the receptors by artificial sweeteners increases the rate of glucose absorption by the gut, and lowers the meal-dependent secretion of a peptide hormone that stimulates insulin secretion by the pancreas. Since insulin normally acts to clear glucose from the circulation, the combined effects of these two changes are expected to result in a bigger surge of blood glucose after a meal than would otherwise occur if were not accompanied by intake of the artificial sweeteners.
“This could have important implications, because the ‘excursion’ of glucose after a meal determines the amount of concentration-dependent ‘damage’ that glucose does to proteins (ranging from those in cells lining our blood vessels to those in our retina). Whether high intake of artificial sweeteners is sufficient to increase the chances of developing type-2 diabetes is still an open question, but it could produce effects that mimic those encountered in diabetic patients with poor control (large excursions) of glucose.”
* ‘Impact of artificial sweeteners on glycaemic control in healthy humans’ by Young et al. was presented at the European Association for the Study of Diabetes (EASD) conference on Thursday 14 September.
Declared interests
Prof. Victor Zammit: No conflicts of interest
Dr Ines Cabola: No conflicts of interest
Dr Ian Johnson: No relevant interests declared.
Prof. Nick Finer: “I am an employee of Novo Nordisk but have no conflicts of interest in relation to this research.”
Dr Abd Tahrani: No conflicts of interest.
No conflicts of interest.