Final answer:
Inulin is a fructosan or polysaccharide that is used both to assess kidney function via the GFR and as a prebiotic fermentable fiber beneficial for gut health.
Step-by-step explanation:
Inulin is a fructosan or a polysaccharide found naturally in many plants. It cannot be metabolized by the human body, which makes it useful in medical tests such as the inulin clearance test to assess kidney function by measuring the glomerular filtration rate (GFR). Inulin offers several health benefits due to its role as a prebiotic fermentable fiber, which promotes the growth of beneficial gut bacteria such as Lactobacillus and Bifidobacterium. It can enhance the absorption of minerals like calcium, magnesium, and iron, but it can also cause digestive distress at higher doses due to rapid fermentation in the intestine.