Study doesn’t find enough evidence related to effects of noncaloric sweeteners on gut microbiota

Reviewed by Kate Anderton, B.Sc. (Editor)Feb 21 2019

The study, carried out by the UGR professor of Biochemistry and Molecular Biology Ángel Gil and his research team, has been published in the scientific journal 'Advances in Nutrition'

There is not enough evidence related to the effects of noncaloric sweeteners on appetite, short term intake, and risk of suffering from cancer or diabetes, according to the conclusions of this review

Noncaloric sweeteners may substitute sugar because they mimic its sweet taste but have a negligible impact on daily energy intake and are frequently sweeter than sucrose

There is currently not enough evidence related to the effects of noncaloric sweeteners on appetite, short?term intake, and risk of suffering from cancer or diabetes, as shown by a study recently published in the scientific journal 'Advances in Nutrition'. This study has reviewed prior evidence about the effects of sweeteners on gut microbiota through experimental research and clinical trials.

According to this review, "it's necessary to carry out further research on the effects of sweeteners on the composition of human gut microbiota as well as confirming any effect that may have been proven in clinical trials on animals," says Ángel Gil, professor of Biochemistry and Molecular Biology from the University of Granada (sUGR) and President of the Iberoamerican Nutrition Foundation (FINUT, from its abbreviation in Spanish).

On this matter, "every sweetener approved in the European Union is safe and its impact on macrobiota is negligible as long as its daily intake is under the ADI (Acceptable Daily Intake). Furthermore, low?calorie sweeteners seem to have beneficial effects since they act as true prebiotics."

Worldwide increase in sugar consumption, especially sucrose or fructose and glucose syrups, has raised concern about its possible adverse effects on human health and the development of chronic diseases such as metabolic syndrome, cardiovascular diseases, and type 2 diabetes. So much so that institutions such as the World Health Organization (WHO) have recommended a reduction in the consumption of these free sugars.

Thus, sweeteners may substitute sugar because they mimic its sweet taste but have a negligible impact on daily energy intake and are frequently sweeter than sucrose.

Critical analysis of the evidence

The main goal of this review has been to critically discuss the evidence supporting the effects of nonnutritive sweeteners (NNSs), both synthetic sweeteners (acesulfame K, aspartame, cyclamate, saccharin, neotame, advantame, and sucralose) and natural sweeteners (NSs; thaumatin, steviol glucosides, monellin, neohesperidin dihydrochalcone, and glycyrrhizin) and nutritive low?calorie sweeteners (polyols or sugar alcohols) on the composition of microbiota in the human gut.

One of the main discoveries is that "the only nonnutritive and noncaloric sweeteners that significantly alter microbiota are saccharin and sucralose, although their impact on human health is unknown and further research should be carried out in order to confirm said alteration," professor Gil explains. "The same could be said about steviol glucosides, although only for intakes greater than the ADI."

"In this sense, sweeteners based on amino acid derivatives don't exert great changes on gut microbiota due to their low concentration and because those amino acids are absorbed by the duodenum and the ileum," emphasizes the president of the FINUT. "With respect to polyol sweeteners (such as isomaltose, maltitol, lactitol, and xylitol), which are poorly absorbed or even not absorbed at all, they may have prebiotic actions and can reach the large bowel and increase the numbers of bifidobacteria in animals and humans."

Besides this study, another review has been recently published in the journal 'Food and Chemical Toxicology', carried out using only in vivo trials. Likewise, "that paper also came to the conclusion that there is no evidence of low?calorie sweeteners exerting adverse effects on gut microbiota," says Gil.

Strict safety control

Noncaloric sweeteners, like the rest of alimentary additives, are subject to a strict safety control carried out by the European Food Safety Authority (EFSA), the U S Food and Drug Administration (FDA), and other international institutions such as the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and the International Agency for Research on Cancer (IARC).

Thus, "the use of sweeteners, which are subject to strict controls by these organizations, is safe as long as they are consumed within the Acceptable Daily Intake," the UGR professor concludes.