Researchers at the University of Cambridge found that common sweeteners can interact with gut bacteria, particularly when combined with other substances like medications.

A study from the University of Cambridge indicates that many common sweeteners can directly interfere with the growth of gut bacteria. Researchers tested 39 sweeteners against 25 bacterial species in a laboratory setting. The findings suggest that these substances are not metabolically neutral and that their effects on microbes can be significantly altered when combined with other compounds, such as food additives or medications.

Impact of Sweetener Combinations

The research, published in Molecular Systems Biology, revealed that sweeteners often interact with other substances found in food and medicine. In over 100 observed cases, the presence of an additional compound changed the effect of a sweetener on bacterial growth, with 34 cases showing a stronger impact and 68 cases showing a weaker one. The most significant result involved the combination of the sweetener isosteviol and the antidepressant duloxetine, which suppressed two bacterial species associated with digestive and metabolic health.

Laboratory Findings and Future Research

When tested in a simplified synthetic microbial community, the combination of isosteviol and duloxetine reduced overall bacterial diversity and altered the community's internal balance. These changes were associated with increased toxicity toward certain host cells and disruption of immune-related cell activity. The scientists emphasize that these experiments were conducted in a laboratory and do not prove that these combinations cause harm in humans, as the human digestive system is far more complex than the models used.