watercress
Meaning of watercress: A peppery salad leaf grown in running water, repeatedly confused in older references with an unrelated plant of a similar name.
Definition of watercress
Watercress is a leafy green plant, Nasturtium officinale, that grows in slow-moving fresh water and is eaten raw in salads, soups and sandwiches. Its peppery taste comes from mustard oils released when the leaves are crushed or chewed. It belongs to the cabbage family and supplies vitamin K, vitamin C and carotenoid pigments.
What gives it the peppery taste?
The leaves store compounds called glucosinolates, which sit harmlessly in the plant until the tissue is damaged. Crushing or chewing brings them into contact with an enzyme that splits them, and the products are pungent mustard oils. The main one in watercress is phenethyl isothiocyanate. That same chemistry runs through the whole cabbage family, and it is why mustard, horseradish and rocket share a related bite.
Is it the same as Indian cress?
No, and older reference works often merge the two. They are different plants from different families that share only a shape of leaf and a sharp flavor.
| Watercress | Indian cress | |
|---|---|---|
| Botanical name | Nasturtium officinale | Tropaeolum majus |
| Family | Cabbage family | Tropaeolaceae |
| Where it grows | In shallow running water | In garden soil |
| Parts eaten | Leaves and stems | Leaves and bright flowers |
Confusingly, the garden plant known as Indian cress is also called nasturtium in everyday speech, while Nasturtium is the formal genus name of watercress. The overlap is a quirk of naming rather than any relationship between the plants.
What is known about health effects?
Phenethyl isothiocyanate has been studied in cell cultures and in animals, where it affects the enzymes that process foreign chemicals. Reports of that work appear in the peer-reviewed literature. Human trials have been small and short, and no clinical benefit has been established. As a food, watercress is a dense source of vitamin K, which matters for people taking anticoagulants whose dose is balanced against a steady vitamin K intake.
Are there risks from wild watercress?
Watercress gathered from streams grazed by sheep or cattle can carry the larvae of the liver fluke, a parasite that reaches the bile ducts after the plant is eaten. Commercially grown watercress is raised in controlled water for that reason.
Also known as
Used in a sentence
The dietary assessment noted a recent increase in watercress intake alongside a change in anticoagulant control.
Good to know
Watercress and Indian cress are unrelated plants that older sources list as one, and the vitamin K content of watercress is relevant to anticoagulant control.
Word origin
Where “watercress” comes from
The genus name Nasturtium comes from the Latin nasus tortus, meaning twisted nose, a reference to the reaction the sharp taste provokes.