‘Sulforaphane is very important,’ says Dr Maria Traka, of the Norwich-based IFR. ‘The evidence suggests that it helps maintain a healthy balance of antioxidants in the body to counter the effects of dietary, environmental, or other carcinogens.

‘To get the benefits, you would need to eat three or four portions of broccoli a week. Some may find that difficult but, having seen the evidence, my family now eat it three or four times a week.’

Sulforaphane is produced by the body when we eat glucoraphanin, a compound found in broccoli.
It is thought sulforaphane turns on genes that boost antioxidant levels and blocks a family of enzymes called HDAC that prevents the body from suppressing tumours.
It may even encourage the body to make other enzymes that excrete carcinogens. 

Research also shows it may stop the development of cancer stem-cells that are resistant to chemotherapy and radiation therapy. The two new trials using broccoli-based medicines are both based in America.

At Johns Hopkins University and the Sidney Kimmel Comprehensive Cancer Center, women with breast cancer are being given sulforaphane daily for two weeks to see if it slows the growth of tumours and increases levels of protective enzymes in breast tissue.

Meanwhile, at the Knight Cancer Institute in Oregon, researchers are looking at whether broccoli extract taken three times a day for up to two months slows the growth of tumour cells.