Maintaining gastrointestinal (GI) microbiome diversity has been shown to improve treatment related mortality in HSCT patients. Interventions to improve GI microbial diversity could be beneficial to this patient population. Diets rich in prebiotics have been shown to increase gut microbial diversity and improve symptoms in other gastrointestinal diseases. Prebiotics are non-digestible carbohydrates that promote growth of commensal organisms in the gut by providing nutrition. Some examples are brown rice, green apples, and tomatoes. Our theory is that consuming a diet rich in prebiotics pre- and during the first 100 days following HSCT will help to reduce acute graft versus host disease (aGVHD) overall, and specifically acute GI GVHD, and clostridium difficile (C.Diff). Participants will be encouraged to eat at least 2 servings of a prebiotic-rich food from time of admission for HSCT through 100 days following HSCT and will be clinically monitored, including for acute GVHD, acute GI GVHD and C.Diff. Stool samples will be collected from all participants about once every 4 weeks.
