Lab Tests Find Common Sweeteners Alter Gut Bacteria
A controlled laboratory study shows many sweeteners change bacterial growth and that some common drug pairings produce larger microbial shifts.
Overview
- The study, published in June 2026, exposed 25 gut bacterial species to 39 commercially used sweeteners and measured direct effects on bacterial growth.
- About three quarters of the sweeteners changed the growth of at least one bacterial species and several stopped or slowed growth of bacteria linked to a healthy gut.
- Researchers tested sweeteners with common additives and eight drugs and found more than 100 interactions where combinations changed sweetener effects on microbes.
- The strongest laboratory finding showed the sweetener isosteviol plus the antidepressant duloxetine sharply suppressed Roseburia intestinalis and Parabacteroides merdae, reduced community diversity, and increased markers of host‑cell toxicity.
- Authors warn the results are from simplified in vitro models and say targeted human and mechanistic studies are needed to determine real‑world health effects and which combinations matter most for people.