Not a nut, and older than most of your groceries

The first thing to clear up is the name, because it's wrong twice over. Tiger nut isn't a nut, and it isn't striped like a tiger for any reason that matters. It's a small tuber — the root of a plant called Cyperus esculentus, about the size of a marble — known as chufa in Spain, earth almond in parts of Europe, and aya in Hausa. Humans have been eating it for a very long time: tiger nuts have been found in the tombs of the pharaohs, they've been a staple in Nigeria and Ghana for centuries, and they're the base of horchata de chufa, the sweet, milky drink Valencia is known for.

That the name misleads actually matters. Despite the "nut," tiger nut contains no tree-nut protein and is safe for people with tree-nut allergies. That makes tiger nut milk one of the few plant milks that steps around both dairy and nut allergens at once — a genuinely useful thing to be able to say plainly.

The part worth understanding, though, is what tiger nut does in the gut. It's unusually rich in fibre and in resistant starch — a form of carbohydrate that isn't broken down in the small intestine but passes through to the large one, where it feeds the bacteria that live there. That is the textbook definition of a prebiotic. In practice it means slow, steady energy instead of a sugar spike, and a microbiome with something to work on rather than around. Old herbal traditions used Cyperus species for digestive complaints; the modern explanation is the fibre.

There's more to it than fibre. Tiger nut is high in monounsaturated fat — largely oleic acid, the same fat that gives olive oil its reputation — along with potassium, magnesium, phosphorus, iron, and vitamins C and E.

And one honest caveat, because the fibre cuts both ways. What feeds a healthy gut can overwhelm a sensitive one. If you're new to it, or your digestion is easily upset, introduce tiger nut slowly and in small amounts; soaking softens it and makes it gentler. For most people, though, it's exactly what it has been for millennia — sweet, nutty, and quietly good for you.