Artificial sweeteners commonly found in low-calorie beverages could negatively impact the gut microbiome by slowing the growth of beneficial bacteria, according to a study from the University of Cambridge.
The research, published in the journal Molecular Systems Biology, examined how 39 commercially used sweeteners affect 25 different species of gut bacteria, including beneficial, neutral, and potentially harmful types. Scientists observed the multiplication rates of these bacteria when exposed to the sweeteners individually and in combination with other compounds like caffeine, flavorings, or medications.
While sweeteners are often marketed as healthier alternatives to sugar, evidence has increasingly linked them to health issues such as type 2 diabetes, obesity, and cancer. Unlike sugar, these substitutes are not digested in the stomach and interact directly with bacteria in the intestines.
One particular finding highlighted that isosteviol, a sweetener derived from the stevia plant, significantly impaired the growth of certain gut bacteria when combined with duloxetine, a widely prescribed antidepressant. This combination was found to strongly suppress two bacterial species crucial for a healthy gut microbiome. Further analysis indicated that this combination also increased toxicity in laboratory-grown cells and interfered with the body's inflammatory and immune responses.
"Sweeteners are often marketed as metabolically neutral, but our study challenges this idea," said Dr. Sonja Blasche, the study's lead author. "We found they can directly affect gut bacteria, particularly when mixed with other compounds such as medication and food additives." The researchers noted that more investigation is needed to fully understand these effects.