Study shows how broccoli fights cancer

By Michael Kahn

LONDON (Reuters) - Just a few more portions of broccoli each week may protect men from prostate cancer, British researchers reported on Wednesday.

The researchers believe a chemical in the food sparks hundreds of genetic changes, activating some genes that fight cancer and switching off others that fuel tumors, said Richard Mithen, a biologist at Britain's Institute of Food Research.

There is plenty of evidence linking a healthy diet rich in fruits and vegetables to reduced cancer risk. But the study published in the Public Library of Science journal PLoS One is the first human trial investigating the potential biological mechanism at work, Mithen added in a telephone interview.

"Everybody says eat your vegetables but nobody can tell us why," said Mithen, who led the study. "Our study shows why vegetables are good."

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 will die from it.

Mithen and colleagues split into two groups 24 men with pre-cancerous lesions that increase prostate cancer risk and had them eat four extra servings of either broccoli or peas each week for a year.

The researchers also took tissue samples over the course of the study and found that men who ate broccoli showed hundreds of changes in genes known to play a role in fighting cancer.

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