A comprehensive laboratory study from the University of Cambridge has found that approximately three-quarters of the 39 commonly used sweeteners tested directly altered the growth of at least one species of gut bacteria, and that sweetener effects changed in more than 100 ways when the sweeteners were combined with medications, caffeine, or food additives. The strongest observed effect involved the combination of isosteviol, a sweetener used in foods and beverages, with the antidepressant duloxetine, which sharply reduced two bacterial species important for digestive health and blood sugar regulation.
The study, published in Molecular Systems Biology on June 25, 2026, and covered by ScienceDaily on July 16, is one of the most comprehensive experimental analyses of sweetener-microbiome interactions yet conducted.
