Cambridge Study Shows Low‑Calorie Sweeteners Disrupt Gut Bacteria

Scientists at the University of Cambridge’s Medical Research Council Toxicology Unit examined how 39 common artificial and low‑calorie sweeteners affect a panel of 25 gut bacterial strains. About 75 percent of the sweeteners altered the growth of at least one type of bacteria, with several slowing the proliferation of beneficial microbes that help regulate blood sugar and immunity. The researchers also tested combinations with other substances such as caffeine, vanilla extract, additional sweeteners and common drugs; more than 100 instances showed the mixture changed the sweetener’s impact, sometimes amplifying and other times reducing the effect. A striking finding was that the sweetener isosteviol, when paired with the antidepressant duloxetine, markedly inhibited two key beneficial bacteria—Roseburia intestinalis and Parabacteroides merdae—reducing overall microbiome diversity in an artificial community model. The study suggests many low‑calorie sweeteners could disrupt the gut microbiome, raising questions about their long‑term health implications.