The direct effects of saccharin on gut microbiota was observed by culturing faecal matter from naïve mice, in the presence of saccharin (5mg/ml) or control growth media. After incubation, the cultures were administered in mice that hadn’t been exposed to saccharin before. In vitro stool culture with saccharin had an increase in the same bacterial phylums as that of the in vivo faecal samples. Transfers of the in vitro samples resulted in a significantly higher glucose intolerance, compared to the mice receiving the control culture.
Shotgun metagenomics sequencing analysis of the in vitro saccharin treatment also showed induction of similar functional alterations as the in vivo saccharin treatment. Glycan degradation pathways were highly enriched in both settings.
Reference: Suez, Jotham et al. ‘Artificial Sweeteners Induce Glucose Intolerance By Altering The Gut Microbiota’. Nature (2014)