Watercress

Nasturtium officinale — the peppery leaf that grows in running water

All articles checked for accuracy against the GB NHC Register and all sources have citations with verified links to their relevant studies.

Watercress is a peppery, fast-growing leaf vegetable that thrives in cool, running water. It is a brassica with a long culinary history and a distinct phytochemical profile centred on gluconasturtiin and its breakdown product, PEITC.

This piece describes watercress as a plant, its traditional use and how it is made up nutritionally and phytochemically. It summarises the shape of the research—mostly preclinical and observational—and explains the regulatory position for botanicals in plain terms.

Ingredient Snapshot

What it is

A peppery, fast-growing leafy green from the mustard family.

Where from

Nasturtium officinale — aquatic perennial grown in cool, running water

Known for

A nutrient-dense brassica rich in vitamin C, vitamin K, folate and glucosinolates.

In WellsparQ

• Electro levels80 mg

Watercress is one of the oldest leaf vegetables in the European diet, a fast-growing aquatic plant with a bright, peppery bite. It belongs to the brassica family — the same broad group as broccoli, rocket and mustard — and shares that family's characteristic pungency and phytochemistry. In the WellsparQ range it is a small, whole-plant addition to a single formula. As a botanical, it carries no authorised health claim, so this piece stays where it should: on the plant itself, its heritage, its make-up and what research has actually examined.

A plant of clean, running water

Watercress (Nasturtium officinale) is a perennial that grows semi-submerged in cool, flowing streams and spring-fed beds ^¹. That habitat is part of its identity — traditional watercress farming uses clean running water, and the plant has been gathered and cultivated across Europe and the Near East for a very long time ^¹². In Britain it became a notable market-garden crop in the nineteenth century, sold in bunches and eaten raw. Its culinary heritage — in soups, salads and as a peppery garnish — is a matter of cultural and historical record, stated here as such rather than as evidence of any benefit.

Botanically it sits in the Brassicaceae (mustard family), which explains both its flavour and its chemistry: like its relatives, it produces sulphur-containing glucosinolates ^²³.

What is in the leaf

Watercress is, first and foremost, a nutrient-dense leafy green with a very high water content and low energy density ^¹³. Nutritionally it is recognised as a source of several vitamins and minerals in the whole-food matrix — including vitamin C, vitamin K, folate, and carotenoids such as beta-carotene and lutein — alongside its characteristic phytochemicals ^³.

Its signature compound is the glucosinolate gluconasturtiin, which on chopping or chewing is converted by the plant's own enzyme (myrosinase) into the isothiocyanate phenethyl isothiocyanate (PEITC) ^²³. This chemistry is common to the brassicas and is the main reason watercress has attracted research attention.

What the research has looked at — framed as evidence

Watercress and its isothiocyanates have been studied largely in laboratory and early-stage settings. Reviews of Nasturtium officinale describe investigations into its glucosinolate/isothiocyanate content and antioxidant properties, and note its long record of traditional and culinary use ^². A 2025 narrative review examined watercress in the broader context of diet and non-communicable disease, summarising the mostly preliminary nature of the human evidence and calling for more rigorous studies ^³.

It is important to be plain about the limits here. Much of this work is preclinical (cell and animal studies) or observational, and it does not establish that a watercress food supplement produces any particular health outcome in people. Under UK/EU rules, watercress — as a botanical — has no authorised health claim, and WellsparQ makes none. What we can say is factual: it is a nutrient-dense brassica with a well-characterised phytochemistry that researchers continue to examine.

Where watercress appears in the WellsparQ range

Watercress is a single, whole-plant entry.

Source: WellsparQ Supplements Database. As a leafy plant it suits vegan, vegetarian and other plant-based diets.

A practical note

Watercress is an everyday food eaten freely in the diet, and a modest supplemental amount sits well within that context. Two small cautions are worth stating. First, because watercress contains meaningful vitamin K, anyone taking warfarin or similar anticoagulants should keep their intake consistent and check with a pharmacist, as they would with any leafy green ^¹. Second, as with any supplement, anyone pregnant, breastfeeding or managing a health condition should speak to a GP or pharmacist before use.

Where it fits your day

Watercress is a heritage leaf — peppery, mineral-rich and grown in running water — and in the WellsparQ range it appears as exactly that: a small, honest, whole-plant addition rather than a headline. We let the plant be what it is: a well-loved brassica with a genuine culinary past and a phytochemistry that research continues to explore.

Rooted in nature. Backed by research.