Research on sweeteners “inappropriate and unjustified”

The Calorie Control Council has responded to research – “Artificial sweeteners induce glucose intolerance by altering the gut microbiota” – published in Nature. Extensive testing on low-calorie sweeteners conducted over several decades has concluded that they do not negatively impact glycaemic indices and insulin, the Council says. Therefore, the recent allegations by Suez et al. […]

The Calorie Control Council has responded to research – “Artificial sweeteners induce glucose intolerance by altering the gut microbiota” – published in Nature.

Extensive testing on low-calorie sweeteners conducted over several decades has concluded that they do not negatively impact glycaemic indices and insulin, the Council says. Therefore, the recent allegations by Suez et al. that “artificial sweeteners” induce glucose intolerance and thus cause obesity by altering the gut microbiome has received considerable attention by both media and the scientific community. However, as discussed below, a careful reading of the details of this paper illustrates that this conclusion is inappropriate and unjustified.

The substantial research conducted on aspartame and sucralose has clearly demonstrated that these compounds do not affect the gut microbiota. Aspartame is completely digested into amino acids and methanol, which are absorbed in the small intestine. Neither aspartame nor its digestion products ever reach the colon; therefore it does not affect gut microbiota. Sucralose is not digested, and passes unchanged to the large intestine. However, numerous studies show pure sucralose cannot be metabolized by microflora.

So how is it possible that these two sweeteners reportedly altered the gut microbiota in this study? The answer is that the researchers inappropriately reported statistics and ignored huge changes in overall diet composition.

In order to achieve statistical significance, the authors combined all three different sweetener groups (n=20/group) together into one group (n=60) and compared against the combined control groups to reach a significant value. So six groups of 20 became two groups of 60, making it impossible to determine which, if any, individual sweetener had a significant effect.

Furthermore, the significant impact on food intake, by adding extremely high doses of sweetener (up to 100 times the acceptable daily intake (ADI)) to drinking water, was ignored. Doses and food intake were reported for just four of the 20 mice per group and for only three days of the 11-week study. As many food components are well known to affect both gut microbiota and glycaemic indices, lack of control and documentation of food intake in both the mice and human studies is a critical flaw.

This study provides no evidence that aspartame or sucralose alters gut microbiota or glycaemic response. In contrast, the observation that saccharin at high doses alters gut microbiota was known in the 1980s, and contributed to the establishment of the ADI for saccharin. Therefore, extrapolation of findings of effects of saccharin on the gut microbiome to all artificial sweeteners has no scientific basis and overlooks well-established differences in chemistry and metabolism. The study also fails to mention the numerous studies demonstrating that use of low calorie sweeteners, including aspartame and sucralose, are beneficial in weight loss and weight loss maintenance programs, the Council said.

The Calorie Control Council, established in 1966, is a US-based international association representing the low- and reduced-calorie food and beverage industry. It represents manufacturers and suppliers of low- and reduced-calorie foods and beverages, including manufacturers and suppliers of more than two dozen different alternative sweeteners, fibres and other low-calorie, dietary ingredients.