A small study done at the University of Southampton, U.K., showed that phen-ethyl isothiocyanate in watercress disrupts the signals from tumours that cause normal tissues to grow new blood vessels to feed cancer cells. Participants, who had all been treated for breast cancer, ate a cereal-bowl-size portion of watercress. The study showed a key protein in the signalling process was affected. Although more research is needed, the study states: “Dietary intake of watercress may be sufficient to modulate this potential anti-cancer pathway.”