Men who eat one or more servings of broccoli per week can reduce their risk of developing prostate cancer, a new British study says.

Researchers from the Institute of Food Research found that men who ate 400 g of broccoli per week over a 12-month period had significant changes in the actions of genes related to the development of cancer.

They also found that men who have prostate cancer can reduce the risk of their tumour becoming more aggressive by following the broccoli-rich diet.

The findings were published in the online journal PLoS One.

Researchers set out to document changes in the genes in the prostate gland before, during and after volunteers consumed either a broccoli-rich or pea-rich diet.

After six months, researchers found that prostate genes in men who consumed a broccoli-rich diet had more changes than genes in men on the pea-rich diet.

As well, the effect of the broccoli-rich diet was even more pronounced in the men who had a gene known as GSTM1. Previous studies have shown that people with this gene actually benefit more from eating broccoli than those who do not have this gene.

“This study provides, for the first time, experimental evidence obtained in humans to support observational studies that diets rich in cruciferous vegetables may reduce the risk of prostate cancer and other chronic disease,” the authors wrote.

Prostate cancer is the most common non-skin cancer in men in western countries.

Lead study author, professor Richard Mithen, said that once scientists understand how different vegetables act on cell expression, “we can provide much better dietary advice in which specific combinations of fruit and vegetable are likely to be particularly beneficial.”

Mithen said that the best advice for men for now is to eat two or three portions of cruciferous vegetables per week. In addition to broccoli, members of the cruciferous family include Brussels sprouts, cauliflower, cabbage, watercress, kale and radish.