FRIDAY July 4, 2008 (foodconsumer.org) -- A study led by British researchers provides more evidence to suggest that eating broccoli often can help prevent prostate cancer.

The study published in the Public Library of Science journal PLoS One showed broccoli triggers hundreds of changes in genes that either suppress the activation of cancer development or shut off the mechanisms promoting the development.

Numerous studies have linked broccoli and other vegetables to decreased risk of cancer. But few offered evidence to suggest that eating broccoli is actually the cause of the reduced cancer risk.

The current study by Richard Mithen, a biologist at Britain's Institute of Food Research and colleagues was meant to investigate the potential biological mechanism for the protective effort against prostate cancer of the vegetable.

For the study researchers recruited 24 men with precancerous lesions that increase the risk of prostate cancer.   Half of the subjects were asked to eat four extra servings of broccoli and the other half were told to eat four servings of peas each week for a year.

Over the course of study, tissue samples were taken from the participants and analyzed to see the difference in genetic changes.

Those who ate broccoli experienced hundreds of changes in genes that are involved in fighting cancer.

The benefit may also be provided by other cruciferous vegetables including Brussels sprouts, cauliflower, cabbage, and watercress, which contain a compound called isothiocyanate, according to the researchers.

One particular compound called sulforaphane in broccoli may also provide some extra protection against cancer.

Prostate cancer is expected to be diagnosed in 186,000 people in the United States in 2008 and 28,660 are expected to die from the disease, according to the National Cancer Institute.

The researchers found eating broccoli was particularly beneficial to those with a gene called GSTM1.   About fifty percent of people carry the gene.   In these people, 400 to 500 of the beneficial genetic changes were observed.

Nutrients and other environmental factors are known to affect the expression of genes that have a direct impact of the risk of all types of cancer including prostate cancer.