Sweeteners may slow down growth of gut bacteria - The Hill

What the report says

The Hill reported that a new University of Cambridge laboratory study suggests some widely used sweeteners can affect the growth of gut bacteria associated with digestive health. The research examined 25 bacterial species, spanning beneficial, neutral and potentially harmful types, and exposed them to 39 natural and artificial sweeteners commonly found in foods and drinks.

According to the report, roughly three-quarters of the sweeteners changed the growth of at least one bacterial species. In some cases, the substances slowed or halted bacteria considered part of a healthy gut environment. The researchers also tested sweeteners alongside other compounds, including caffeine, vanillin, advantame and eight common medications, to see whether combinations changed the effects.

The study found more than 100 interactions in which sweeteners acted differently when paired with other substances. The Hill reported that 34 combinations made the effects stronger, while 68 reduced them. One sweetener, isosteviol, was linked in the lab tests to suppression of Roseburia intestinalis and Parabacteroides merdae, two bacteria associated with gut health; the article also noted an association between isosteviol and the antidepressant duloxetine.

The findings matter because artificial and natural sweeteners are common in processed foods and beverages, while the gut microbiome is increasingly studied for its role in digestion and broader health. However, the reported experiments were conducted outside the human body, so they do not prove that consuming these sweeteners causes specific health effects in people. The researchers said further studies are needed to understand how sweeteners, medications and other dietary compounds may interact with gut microbes.