Inuline

Inulin, also spelled inuline in some languages, is a naturally occurring polysaccharide composed of fructose units linked by β-(2→1) glycosidic bonds, with a terminal glucose residue. It is classified as a fructan and occurs in various plant species as a storage carbohydrate. Inulin is not digested by human intestinal enzymes; it reaches the colon where gut bacteria ferment it, producing short-chain fatty acids. It behaves as a soluble dietary fiber with a relatively low caloric value per gram and is often used as a prebiotic component.

Common natural sources include chicory root (Cichorium intybus), Jerusalem artichoke, onions, garlic, leeks, and asparagus; bananas and some grains also contain inulin-type fructans. Industrially, inulin is extracted from chicory roots and refined to produce inulin for use as a dietary fiber additive and as a sugar substitute. Its degree of polymerization typically ranges from about 2 to 60, affecting solubility and fermentability.

In foods, inulin acts as a bulking agent, texture enhancer, and mild sweetener. It can improve calcium and mineral absorption in some contexts and may have beneficial effects on the gut microbiota by promoting bifidobacteria; however, evidence is variable. High intakes can cause flatulence, bloating, and abdominal discomfort, particularly in people with irritable bowel syndrome or sensitivity to FODMAPs.

Regulatory status varies by region, but inulin and oligofructose are widely used as dietary fibers and approved ingredients in many fortified foods. It is generally regarded as safe when consumed within typical amounts.