Eating raw watercress every day may reduce risk of cancer

Watercress is a natural super-food that could help to reduce the likelihood of developing several types of cancer, researchers say.

A study by the University of Ulster suggests that the aquatic plant’s green leaf contains compounds that help to prevent damage to the DNA in white blood cells — which is considered to be an important trigger in the development of cancer.

Eating raw watercress regularly in a salad or sandwich appears to raise levels of the beneficial compounds and cut levels of harmful compounds in the blood.

The study was funded by the Watercress Alliance, a group of watercress growers, but the findings have been independently endorsed by scientists and published in the American Journal of Clinical Nutrition.

Previous studies have suggested that eating increased amounts of cruciferous vegetables is linked to a reduced risk of contracting a number of cancers, including lung, breast and stomach.

As part of the latest study, 60 healthy volunteers, including 30 smokers, ate an 85g bag of fresh watercress every day for eight weeks.

DNA damage to white blood cells was cut by an average of 22.9 per cent, the researchers found. The cells were also more able to protect themselves.

The beneficial effects were found to be greatest among the smokers. When cell samples were exposed to hydrogen peroxide, which generates large numbers of free radicals, damage levels were 9.4 per cent lower than would normally be expected.

Scientists said that high levels of phenylethyl isothio-cyanate (PEITC), a mustard oil which gives watercress, rocket and other green leaves their slightly bitter taste, could be responsible for the effect, by encouraging the body’s natural protective enzymes to fight cancer.

An alternative or complementary explanation was that levels of antioxidant compounds, such as lutein and beta-carotene, were also raised in the blood of the volunteers who ate watercress.

The scientist who led the study, Professor Ian Rowland, who is now at the University of Reading, said: “Blood cell DNA damage is an indicator of whole body cancer risk. The results support the theory that consumption of watercress is linked to an overall reduced risk of cancer at various sites in the body.”

Natural healer

- Weight for weight, watercress contains more Vitamin C than an orange, more calcium than milk, more iron than spinach and more folate than bananas

- It was noted for its reputed health benefits by the Ancient Persians, Greeks and Romans and also by the Victorians

- Hippocrates, the Greek physician, is said to have located his first hospital close to a stream in order to grow fresh watercress to treat his patients

- It was used to combat stuffy nose, coughs, and congestions and as a tonic for Greek soldiers going into battle. The botanical name for the plant comes from a Roman term meaning “twisted nose”

- Nicholas Culpepper, the 17th-century herbalist, claimed that watercress could cleanse the blood

- Sales of watercress in Britain are worth about £55 million a year