Eating a Mediterranean diet with plenty of fruits and vegetables could reduce the risk of being diagnosed with prostate cancer, new research suggests.

Two studies by the University of South Australia have examined the role of micronutrients in preventing what is Australia's most commonly diagnosed form of cancer.

More than 24,000 men were diagnosed with prostate cancer last year and about 3500 died of the disease, according to the Cancer Council.

The studies, published in the journal Cancers, looked at micronutrient plasma concentrations in prostate cancer patients.

Compared to a healthy control group, they revealed low levels of lutein, lycopene, alpha-carotene and selenium, as well as high levels of iron, sulphur and calcium.

Foods rich in lycopene include tomatoes, melons, papayas, grapes, peaches, watermelons and cranberries.

Selenium-rich foods include white meat, fish, shellfish, eggs and nuts.

Co-author Permal Deo said while other risk factors such as ethnicity, family history and age had previously been linked to prostate cancer, nutritional deficiencies associated with the disease remained largely unknown.

He said the findings suggested there were benefits to eating foods that were naturally rich in lycopene and selenium as opposed to taking supplements.

"Our recommendation is to adopt a Mediterranean diet enlisting the help of a dietician because people absorb nutrients in different ways, depending on the food, the digestive system, the person's genotype and possibly their microbiome," Dr Deo said.

"There is strong evidence that being overweight and tall increases the risk of prostate cancer.

"Diets high in dairy products and low in vitamin E may also increase the risk but the evidence is less clear."

Eating foods rich in lycophene and selenium could also speed up recovery among men who underwent radiation treatment for the disease, he said.

Increased DNA damage after radiation exposure was found to be associated with low concentrations of lycopene and selenium in blood plasma.