Rosemary

Why rosemary is anti-inflammatory

Rosemary is anti-inflammatory, and the compound doing most of that work is carnosic acid. It sits in the needles alongside a close relative, carnosol, and between them they account for almost all of the leaf’s antioxidant activity. In laboratory tests, both slow an enzyme that white blood cells use to build leukotrienes, the signals that call more immune cells to a sore spot.

The enzyme work was measured on human cells in a dish, at concentrations far above anything a meal delivers. In people the picture is thinner. Adults who took a rosemary and ginger extract for four weeks showed no change in the inflammation markers in their blood. What happens in cells has not yet turned up in someone eating the herb.

Fresh rosemary is sold as woody sprigs, dried rosemary as whole needles or a ground powder. Whole needles hold their oils far longer than powder, which loses most of its smell within months of opening. Capsules of rosemary extract are a different product, with far more carnosic acid than cooking delivers. Rosemary essential oil is not a food: it goes on the skin or in a diffuser, never in your mouth.

The leaves are tough, so chop them small or drop in a whole sprig and remove it before serving. Carnosic acid dissolves in fat rather than water, so warm olive oil draws more of it out of the leaves than stock does. A teaspoon of dried rosemary in a roasting tin is a normal amount, and nothing about the herb calls for more.