Predicting Fiber Specificity on Gut Microbiome Modulation

Dietary fibers are crucial in shaping gut microbial composition and functionality. Physical complexity and chemical interactions between fibers and the gut environment lead to diverse and specialized responses that involve entire food webs of gut bacteria; however, there is comparatively less emphasis on understanding ecological dynamics to predict these outcomes. These responses may potentially promote either a broader (less specific) or narrower (more specific) group of gut bacterial taxa, which may vary across individuals. This review examines fiber specificity at the organismal and community levels by exploring mechanistic interactions among dietary fibers and gut bacteria. We discuss the interplay of exogenous and endogenous factors and the structure-function relationships influencing fiber specificity. We establish a mathematical framework to describe specificity in fiber-microbiome interactions based on directionality, magnitude, and stochasticity of fiber-microbiome ecological responses. Finally, we identify research gaps to enhance fiber-microbiota predictions, with implications for strategies aimed at optimizing fiber design.