The University of Reading is playing a leading role in a new study which will examine the effects of eating watercress on breast cancer patients.

Two hundred patients in Lisbon are taking part in an eight week dietary trial, funded by producers in Portugal and the UK, in conjunction with the University of Lisbon and the University of Santa Maria.

The women volunteers will be in the early stages of breast cancer. 100 will be in a control group, and the other 100 being asked to eat a 100g bag of fresh watercress a day over eight weeks of treatment. Blood samples will be taken from the volunteers and sent to the University of Reading for expert analysis after eight weeks, three months, one year and three years.

The trial, which begins during Breast Cancer Awareness Month (October), is part of an international study aimed at demonstrating the importance of a healthy diet during radiotherapy treatment. It hopes to build on previous research which has identified several compounds within watercress that may have significant cancer fighting properties.

Breast cancer is the most common cancer in the UK, with about 50,000 women diagnosed each year. It is the second biggest cause of death from cancer in women, with about 12,000 losing their lives from the disease.

Ian Rowland, Professor of Human Nutrition at the University of Reading, commented: "Examining the relationship between diet and the risk of chronic disease is crucial in fighting killers such as breast cancer. This particular study will focus on the role of watercress in enhancing the body's response to radiotherapy as well as protecting against skin damage, sometimes an unfortunate side effect of radiotherapy. If the diet is shown to be effective, the results will be shared with other health professionals to highlight the importance of maintaining a when undergoing radiotherapy."

While at the University of Ulster, Coleraine, Professor Rowland led a 2007 study which showed that eating watercress daily can play a role in cancer prevention. The study showed watercress can significantly reduce DNA damage to blood cells and increase the ability of those cells to resist further DNA damage.

Watercress is grown in mineral rich spring water, drawn from deep under the Chalk Downs of Hampshire, Dorset and Wiltshire. Gram for gram it contains more iron than spinach, more vitamin C than oranges, more calcium than milk, more vitamin E than broccoli and more folate than bananas.

The curative properties of watercress have been revered down the centuries; Hippocrates, the father of medicine, is said to have located his first hospital close to a spring to ensure a supply of fresh watercress to help treat his patients, Greek soldiers were given it as a tonic before going into battle and the 16th Century herbalist Culpepper claimed it could cleanse the blood.