A few portions of broccoli each week may protect men from prostate cancer, British researchers said as quoted by media reports Wednesday. The researchers took tissue samples in the long-term study and found that men who ate broccoli regularly showed hundreds of changes in genes known to play a role in fighting prostate cancer.

"When people get cancer some genes are switched off and some are switched on, what broccoli seems to be doing is switching on genes which prevent cancer developing and switching off other ones that help it spread." said Richard Mithen, a biologist at Britain's Institute of Food Research.

The benefit would likely be the same in other cruciferous vegetables that contain a compound called isothiocyanate, including Brussels sprouts, cauliflower, cabbage, rocket or arugula, watercress and horse radish.

"You don't need a huge change in your diet, just a few more portions makes a big difference," researchers added.

Prostate is the second-leading cancer killer of men after lung cancer. Each year, some 680,000 men worldwide are diagnosed with the disease and about 220,000 die from it.