Impact of High Dietary Fiber on Microbiome and Vaccine Responses

Primary Objectives: --To determine the feasibility of two dietary intervention strategies focused on fiber-rich and prebiotic foods prior to seasonal influenza vaccination. Feasibility is defined as ≥ 80% of subjects being compliant with the intervention. Secondary Objectives: * To evaluate the effects of each dietary intervention on the composition, diversity and function of the gut microbiome. * To assess the effects of each dietary intervention on response to influenza vaccination as measured by vaccine-specific immune response. * To assess the effects of each dietary intervention on systemic immunity. Exploratory Objectives: * To interrogate the overlap between the identified gut microbial and dietary patterns associated with vaccine response and those associated with excellent or poor responses to cancer immunotherapy (from our own published work and internal cohorts). * To identify components and determinants of the gut microbiome that could be modulated to enhance vaccine response. * To determine how modulation of the gut microbiome can be achieved through fiber and prebiotic-focused dietary changes.