March 25/London/The Express -- Consuming oily fish just once a week could help men to survive prostate cancer, scientists revealed.

A study shows a diet rich in omega-3 fatty acids found in fish such as herring, salmon and mackerel could prevent development of the deadly disease. The oils are also believed to be able to block the spread of existing tumor cells, acting as a kind of treatment.

Leaders of a study say that just one 3oz portion of fish a week could reverse the effect of a deadly inherited gene which can cause an aggressive form of the disease.

Their findings showed that a high intake of omega-3 could reduce the risk of developing prostate cancer by almost 60%. More than 35,000 men in the U.K. are diagnosed with the disease each year, and 10,000 die from it.

Medical experts and nutritionists welcomed the study, which backed previous research and suggests the fatty acids could mean the difference between life or death.

Nutritionist Carina Norris said, "Hardly a month goes by without scientists finding more benefits of fish oil. My advice to everyone would be to get as much of it as possible.

"I would advise the use of supplements as hardly anyone in the U.K. eats enough oily fish in their diets. I am reluctant to use the expression, but I would say fish oil is the closest you can get to a superfood."

Leading cancer organisations in Britain also backed the study.

John Neate, chief executive of The Prostate Cancer Charity, said, "It makes sense for men to adopt a healthy diet and lifestyle, and a suggestion to increase the intake of omega-3 is a common part of that. This might improve their chances against developing prostate cancer, but it could also protect against other health problems that affect middleaged and older men."

The findings, published in the U.S. journal Clinical Cancer Research, were uncovered by researchers at the University of California in San Francisco. Their study compared the diets of 466 men diagnosed with the disease and 478 healthy men.

A diet questionnaire was used to assess participants' eating habits.

Men who ate omega-3 rich "dark" oily fish such as mackerel, salmon and sardines between one and three times a month were found to have a 36% lower risk of developing prostate cancer than those who never ate fish.

Men who ate oily fish once a week or more had an astonishing 57% reduction in risk. Similar results were found in men who eat shellfish, which also contain fatty acids.

Researchers found men's omega-3 intake had a significant impact on the effect of a variant of the COX-2 gene, which is linked to prostate cancer.

Men with the inherited gene are more than five times more likely to develop prostate cancer, but the scientists found a high consumption of oily fish wiped out this risk factor.

Professor John Witte, who led the research, said, "The increased risk was reversed by increasing omega-3 fatty acid intake by a half a gram per day. The strongest effect was seen from eating dark fish one or more times per week."

A study at Manchester's Christie Hospital also found evidence that omega-3 oil helps to stop tumour cellss preading in prostate cancer victims.

From the March 30, 2009, Prepared Foods E-dition