Inulin is a heterogeneous collection of fructose polymers produced by plants of the Compositae family, most notably by chicory root. It belongs to a class of dietary fibers known as fructans and functions as a natural storage carbohydrate. Due to the specific structure of its β(2,1) linkages, inulin cannot be hydrolyzed by the endogenous secretions of the human digestive system, although it can be metabolized by microbial flora of the colon. As such, in terms of dietary nutrition, inulin is considered a form of soluble fiber and is sometimes categorized as a prebiotic. It is frequently used to measure kidney function via glomerular filtration rate, since it is neither secreted nor reabsorbed at the nephron.
