A University of Cambridge laboratory study found that many common sweeteners directly influence the growth of gut bacteria. The effects often changed when sweeteners were combined with medications or other substances. Researchers stressed that further human studies are needed to understand any health implications.
The research, published in Molecular Systems Biology, tested 39 sweeteners against 25 bacterial species. About three-quarters of the sweeteners affected bacterial growth in at least one species. Several reduced or stopped the growth of bacteria linked to digestive health.
The strongest impact occurred when isosteviol was paired with the antidepressant duloxetine. This combination sharply reduced two beneficial bacterial species and lowered overall microbial diversity in a simplified community model.
Professor Kiran Patil said most knowledge about sweeteners comes from animal or population studies. Dr. Sonja Blasche noted that sweeteners are rarely consumed alone and are often mixed with drinks, snacks, or medications.
The team identified more than 100 interactions where effects strengthened or weakened depending on other compounds present. The scientists cautioned that the lab conditions do not replicate the full complexity of the human digestive system.
