The effects of dietary fiber fermentation products on skin-resident cells

Abstract

Dietary fibers induce compositional shifts in taxa, including enrichment of beneficial SCFA-producing genera such as Faecalibacterium and Roseburia under β-glucan and lactobionic acid. Fiber-mixed induced the most diverse shift, however, the increase of Prevotella and Collinsella under fiber-mix stimulation highlights the complexity of fiber interventions. Overall, these findings are relevant because many of these taxa are associated in inflammatory skin conditions, suggesting that targeted fiber interventions could help restore microbial balance and support skin health. However, donor-specific variability highlights the need for personalized approaches, as the same fiber may exert contrasting effects depending on baseline microbiota composition. Skin cell exposures experiments revealed that fermentation supernatants induced IL-8 secretion in dermal fibroblasts, indicating a pro-inflammatory response. This contrasts with the expected anti-inflammatory role of SCFAs and may reflect the presence of bacterial components such as LPS, which can activate TLR4/NF-κB signaling. These results underscore the complexity of gut-skin interactions and the importance of distinguishing SCFA effects from other microbial products.