Research from the Weizmann Institute reveals that some low- and no-calorie sweeteners can alter gut bacteria and impact glucose handling, adding to existing concerns about their health effects.
Researchers at the Weizmann Institute of Science say a controlled trial has found that some widely used low- and no-calorie sweeteners may alter the human gut microbiome and change the way the body handles glucose. The findings add to a growing body of evidence that sugar substitutes are not biologically neutral, even if they remain approved for use in many countries.
In the trial, 120 volunteers who had not recently consumed products containing artificial sweeteners were split into six groups. Four groups received different sweeteners , saccharin, sucralose, aspartame and stevia , while two groups received none. After two weeks, the researchers reported changes in the composition and function of gut microbes, with the effects varying by sweetener and by participant. According to the Weizmann Institute’s account of the study, saccharin and sucralose were associated with the clearest changes in glucose handling.
The gut microbiome is the community of bacteria and other microorganisms living in the digestive tract, and it has become a major focus of diabetes and obesity research because of its role in digestion, metabolism and inflammation. The Weizmann team said the results suggest sweeteners can influence that ecosystem in ways that may matter for blood sugar control, although they stressed that the study was not designed to show long-term health outcomes.
That caution matters. A long-term risk signal was not established, and the findings do not prove that sugar substitutes cause disease. Still, the work strengthens concerns raised by earlier research. A 2019 paper in Springer found that some food additives, including artificial sweeteners, can change gut bacteria and their ability to ferment fibre, while a more recent study in iScience reported that sweetener use was linked to altered microbial diversity and bacterial abundance in the duodenum, the first part of the small intestine.
Health guidance remains more measured. The NHS says approved sweeteners are assessed for safety before they are allowed on the market and can be a reasonable alternative to sugar when used within recommended limits. It also notes that the evidence on weight and health outcomes is mixed: some short-term studies suggest replacing sugary drinks with low- or no-calorie alternatives may cut energy intake, while longer studies have produced less consistent results. Johns Hopkins Medicine says human studies generally support the safety of sweeteners within acceptable daily intake levels, but adds that research into possible health effects is still under way. The same institution warns that while sugar is not inherently toxic, frequent intake of added sugar is linked to higher blood glucose, insulin resistance, obesity and a greater risk of type 2 diabetes.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
