These dangers lurk when consuming sweeteners

In order to lose weight, many people resort to substitute products with sweeteners. Why, in the worst case, it can have exactly the opposite effect.

Healthy and calorie-free feasting with sugar-free sweeteners – this campaign has persisted for many years. Many products entice you with being just as sweet as conventionally sweetened foods, but without having to be counted on the calorie account.

There was also a tailwind from science, which for a long time assumed that the consumption of sweeteners had no effect on physical health. This picture has changed in recent years. A study published in the journal Cell investigated how healthy four popular sweeteners really are.

An animal study by the Weizmann Institute for Science and the German Cancer Research Center from 2014 provided the first clues. A team led by the immunologist and microbiome researcher Eran Elinav found that the consumption of the calorie-free sweeteners aspartame, saccharin, stevia or sucralose – so-called non-nutritional Sweeteners – has an unfavorable effect on the animals’ glucose metabolism.

The researchers’ observation: Although the sweeteners have no calories, an increase in blood sugar was observed in the animals after a meal. Impaired glucose tolerance is a risk factor for obesity and type 2 diabetes.

If the animals had previously been treated with antibiotics, which also kill off intestinal bacteria, glucose tolerance – the body’s ability to regulate blood sugar levels – was not affected. The researchers concluded from this that there is a connection between intestinal bacteria and the change in glucose metabolism.

As part of a randomized study with 120 healthy people, Elinav and his team investigated whether the results of the mouse study can also be transferred to the human microbiome.

For this purpose, the subjects took either two sachets of aspartame, saccharin, stevia or sucralose daily for two weeks. The control groups took either regular glucose or a placebo. The concentrations of the various sweeteners were all below the daily dose approved by the Food and Drug Administration (FDA) and are not considered harmful.

The result of the study, as reported by Elinav after its completion: “In the subjects who consumed the non-nutritional sweeteners, we were able to detect very significant changes in the composition and function of the gut microbes and the molecules that they secrete into the peripheral blood .”

The change was interpreted as an indication that the intestinal microbes in the human body are very sensitive to each of these sweeteners. The study also found that saccharin and sucralose significantly impair glucose tolerance in healthy adults.

In a further step, stool samples with certain intestinal bacteria were transferred to mice. Animals that received gut bacteria from subjects whose microbiome had changed the most during the 2-week treatment (“top responders”) developed the same impaired glucose tolerance as in humans. If the animals had received other bacteria, there was no reaction.

The study thus proves that the consumption of sweeteners changes the human microbiome in a way that can disrupt glucose metabolism. However, more long-term studies are needed to find out what clinical effects these changes can cause.