Microbial metabolism of specific dietary components, such as fiber,
contribute to the sophisticated inter-kingdom dialogue in the gut that
maintains a stable environment with important beneficial physiological,
metabolic, and immunological effects on the host. Historical changes in
fiber intake may be contributing to the increase of allergic and
hypersensitivity disorders as fiber-derived metabolites are
evolutionarily hardwired into the molecular circuitry governing immune
cell decision making processes. In this review, we highlight the
importance of fiber as a dietary ingredient, its effects on the
microbiome, its effects on immune regulation, and potential mechanisms
for dietary fibers in the prevention and management of allergic
diseases. In addition, we review the human studies examining fiber or
prebiotic interventions on asthma and respiratory outcomes, allergic
rhinitis, atopic dermatitis, and overall risk of atopic disorders. While
exposures, interventions and outcomes were too heterogeneous for
meta-analysis, there is significant potential for using fiber in
targeted manipulations of the gut microbiome and its metabolic functions
in promoting immune health.