March 10, 2009

Vegetables may reduce prostate cancer risk

A diet high in vegetables can reduce the risk of prostate cancer, researchers in China suggest.

Ruth Chan of The Chinese University of Hong Kong and colleagues examined more than 100 studies and concluded that the primary mechanism of this positive vegetable effect is antioxidant protection against DNA and cell damage.

The researchers said tomatoes and their byproducts contain the carotenoid antioxidant lycopene. Overall, studies for tomatoes and lycopenes show inconsistent results on decreasing cancer prostate risk, but lycopene based foods are probably protective, reported.

Yellow orange vegetables contain the antioxidant beta-carotene. Data on beta-carotene and prostate risk from cohort and case-control studies were inconclusive.

Flavonoids are a carbon structure compound ubiquitously present in plant foods and have antioxidative and anti-inflammatory properties. Overall there is some evidence suggesting that consumption of legumes, including soy and soy products, is protective against prostate cancer.

Data on allium vegetables -- garlic, onions, leeks, chives, scallions and shallots -- suggest a protective benefit, but population based studies are limited. Cruciferous vegetables include broccoli, cauliflower, brussels sprouts, cabbage, bok choy, collard greens and kale have anticarcinogenic properties, but population-based studies are limited, the researchers said.

The findings are published in the journal Molecular Nutrition and Food Research.