Broccoli contains sulforaphane, which seemed to kill off cancer stem cells in tests. According to scientists, broccoli could hold the key to preventing and even treating breast cancer.
A chemical found in the vegetable superfood targets the cells that fuel the growth of tumours – a factor causes the cancer.
Broccoli contains high levels of sulforaphane which can kill these cancer stem cells and prevent the disease from developing, or spreading when it is established.
U.S. scientists at the University of Michigan Comprehensive Cancer Centre completed successful laboratory tests on mice and cell cultures.
Study author Professor Duxin Sun said: ‘Sulforaphane has been studied previously for its effects on cancer, but this study shows that its benefit is in inhibiting the breast cancer stem cells.
‘This new insight suggests the potential of sulforaphane or broccoli extract to prevent or treat cancer by targeting the critical cancer stem cells.’
A report on the findings is published in the Clinical Cancer Research journal.
Around 46,000 cases of breast cancer are diagnosed each year in Britain, with 12,000 dying from the disease. Current chemotherapy regimes do not work against cancer stem cells, which is why the disease recurs and spreads, say the researchers.
They believe that eliminating the cancer stem cells is critical to controlling the growth of tumours.
In the study, researchers took mice with breast cancer and injected varying concentrations of sulforaphane from the broccoli extract.
They then used several established methods to assess the number of cancer stem cells in the tumours.
These measures showed a marked drop in the cancer stem cell population after treatment with sulforaphane, with little effect on the normal cells. Furthermore, cancer cells from mice treated with the chemical were unable to generate new tumours.
The researchers then tested the compound on human breast cancer cell cultures in the lab, finding a similar fall in the number of cancer stem cells.
However, they warned that the concentrations used in the study were higher than those found in broccoli.
Because their work has not been tested in patients, they advise people against adding sulforaphane supplements to their diet in anticipation that it might prevent or treat cancer.
They are currently developing their own method to extract and preserve the chemical and will then carry out a clinical trial to test the process.
The vegetable’s characteristically bitter taste means it is disliked by many – including former U.S. president George W. Bush.
But its health effects are widely recognised, with studies showing that a chemical in the vegetable boosts DNA repair in cells.
Other evidence suggests it keeps arteries healthy and may reverse the damage caused by diabetes to heart blood vessels.
It is high in vitamin C and fibre, and one stalk can provide nearly twice the recommended daily intake of vitamin K for an adult.