INS and metabolic syndrome: IL-8 is a key chemokine bringing neutrophils and macrophages to sites of inflammation and contributing to the proinflammatory profile characteristic of metabolic syndrome.21 This chemotaxis can subsequently impact processes that impair insulin signalling,21 and studies have associated elevated levels of IL-8 with increased insulin resistance in humans.36 37 Consequently, the inhibition of IL-8 by IPE supplementation appears to be driven by the selective delivery of propionate to the colon and may partly explain the observed improvements in glucose homeostasis.