A compound found in watercress can suppress the growth of breast cancer cells by turning off a signal in the body. When that happens, the flow of essential blood and oxygen to the growing tumour stops is stemmed, and the cancer cells stop developing.
Researchers from the University of Southampton discovered watercress's cancer-fighting abilities when they gave a group of cancer survivors a bowl each - around 80g - of watercress and monitored them for the following 24 hours.
Not surprisingly, they found very high levels of the watercress's plant compound PEITC in the participants' blood samples afterwards - but it had affected the protein that helps nourish cancer cells.
Research team leader Prof Graham Packham commented: "The research...shows that eating watercress may interfere with a pathway that has already been tightly linked to cancer development."
(Source: University of Southampton press conference, 14 September 2010).