Ultra-processed Food Consumption, Gut Microbiota, and Glucose Homeostasis

Advancing age is associated with gut dysbiosis, low-grade chronic inflammation, progressive insulin resistance, and increased risk of type 2 diabetes (T2D). Prediabetes is present in 45-50% of middle-aged/older adults, and declines in glucose tolerance are evident in the third or fourth decade of life. Thus, there is an urgent need to identify new approaches for the prevention of type 2 diabetes among middle-aged adults. Observational research has linked intake of ultra-processed foods (UPF), which comprise \~60% of total energy intake in US adults, with increased risk of T2D. Ex vivo and animal research suggests that components of UPF alter gut microbiota composition and initiate a cascade of events leading to intestinal inflammation and impaired glycemic control. Whether mid-life adults (aged 45-65 yrs) are susceptible to the adverse impact of UPF consumption on glucose homeostasis is unknown. The overall objective of this study is to establish proof-of-concept for an impairment in glucose homeostasis following increases in UPF consumption in mid-life adults, in order to conduct a larger, more comprehensive and mechanistic trial in the future. In addition, changes in gut microbial composition and function, intestinal inflammation and permeability, serum endotoxin concentrations, and inflammatory cytokines as potential mechanisms by which UPF consumption influences glucose homeostasis will be investigated.