A sweetener used in food and drink products sharply reduced the growth of beneficial gut bacteria when combined with a common antidepressant, according to laboratory research from the University of Cambridge in the United Kingdom. Scientists tested 39 sweeteners and found more than 100 cases in which these compounds behaved differently when mixed with medications, caffeine, or flavorings. The strongest effect came from pairing isosteviol with the antidepressant duloxetine.
Isosteviol plus duloxetine hit two key bacterial species
The combination of isosteviol, a sweetener used by the food and beverage industry, and duloxetine reduced the growth of two bacterial species that are important for digestive health, blood sugar regulation, and immune function. The study also found that many commonly used sweeteners can directly change the growth of gut bacteria on their own. The researchers identified more than 100 instances in which sweeteners interacted unexpectedly with other substances.
Sweeteners appear in soft drinks, snacks, and even medications
Sweeteners are found in countless everyday products, including soft drinks, candy, desserts, breakfast cereals, snacks, and some medications. They are often promoted as alternatives that provide sweetness with less sugar or fewer calories. However, growing evidence has linked sweetener consumption with conditions including type 2 diabetes, obesity, and cancer. These associations do not prove that sweeteners directly cause those diseases, and researchers are still working to understand the biological processes that might explain the connections. One possible factor is the gut microbiome, the community of bacteria and other microorganisms living in the digestive system. These microbes help break down food, produce useful compounds, train the immune system, and influence metabolism. Changes in the number or balance of these organisms may affect health throughout the body.
Laboratory findings need real-world confirmation
The study was published in Molecular Systems Biology. The scientists caution that the experiments were conducted in a laboratory rather than in people. More research will therefore be needed to determine whether the bacterial changes lead to meaningful health effects under real-world conditions. The findings add to a growing body of evidence that sweeteners may not simply pass harmlessly through the body, especially when consumed alongside medications or food additives.
