Dynamic Microbiome Responses to Structurally Diverse Anthocyanin-Rich Foods in a Western Diet Context

Background/Objectives: Anthocyanin (ACN)-rich foods are known to influence the gut microbiota composition, but the temporal dynamics and structural specificity of these effects remain poorly understood. This study investigated how distinct ACN-rich fruit supplements impact the gut microbiome over time in the context of a Western-style diet. We hypothesized that ACN-induced microbial shifts would occur rapidly, differ by ACN source, and require continued intake to persist. Methods: C57BL/6J mice were fed the total Western diet (TWD) supplemented with freeze-dried powders from bilberry (BB), tart cherry (TC), chokeberry (CB), elderberry (EB), black currant (BC), or black raspberry (BRB) for 0, 1, 3, or 7 days. Cocoa polyphenols (CPs) were included as a comparator with a distinct polyphenol profile. Fecal microbiota were collected at 0, 1, 3, and 7 days post exposure and analyzed by 16S rRNA sequencing. Results: ACN-rich supplements induced rapid microbial shifts detectable within one day of exposure. However, most changes reverted toward the baseline within days of supplement withdrawal, indicating limited persistence. Among the ACNs, BRB produced the most sustained microbiome alterations. Microbial responses varied by ACN source, suggesting that differences in glycoside and aglycone structures influence the community composition. Conclusions: ACN-rich foods can induce rapid but largely transient alterations in the gut microbiome, with variability linked to the polyphenol structure. These findings highlight the ecological sensitivity of the microbiome to specific dietary components and underscore the importance of sustained intake for maintaining microbial shifts.