Inulin

Inulin is a fructan, a chain of fructose that humans cannot digest. It is a soluble fibre with strong prebiotic power: it selectively feeds the good bacteria (notably bifidobacteria).

The original angle (the star prebiotic… and its downside): inulin is one of the best-documented prebiotics. Fermented in the colon, it produces short-chain fatty acids (butyrate), supports immunity, improves calcium absorption and helps regulate blood sugar.

Industry loves it: it lets manufacturers claim “source of fibre” on processed products, improves texture (replacing fat or sugar) and has a mildly sweet taste. You find it in bars, yoghurts, substitutes and “slimming” products.

BUT the downside: inulin is a FODMAP (fructan). In quantity, it causes bloating, wind and discomfort, especially when it is added in concentrated form to industrial products. Many people who “can’t digest” certain bars or substitutes are in fact reacting to the added inulin. People with IBS are particularly sensitive to it.

The difference between natural inulin (in a Jerusalem artichoke, with its food matrix) and added inulin (concentrated in a processed product) is important: the latter is more likely to cause problems because of its dose and isolated form.

Natural sources: chicory root (the richest), Jerusalem artichoke, salsify, garlic, onion, leek, asparagus, banana. Introduce it gradually to give your microbiome time to adapt.