Snacking on walnuts 'helps to prevent prostate cancer' Last updated at 8:30 AM on 23rd March 2010 A handful of walnuts a day could help keep prostate cancer at bay. Snacking on the nuts can cut the size of tumours and slow their growth, research shows. Although the experiments were carried out on mice, the researchers believe they are relevant to humans. Cancer prevention: Walnuts are high in health-boosting chemicals They advise that men add around 14 shelled nuts to their diet for optimal health. Prostate cancer is the most common cancer among men and the second highest killer after lung cancer. Some 35,000 Britons are diagnosed with it each year, and 10,000 die. Although the causes of the disease are not entirely clear, it is known to be linked to diet, and tends to be most common in those who eat fatty meals low in fruit and vegetables. Walnuts, which are naturally high in a host of health boosting chemicals, including omega-3 fatty acids, have already been shown to help stave off breast cancer and heart disease. In the latest study, University of California researchers studied mice genetically prone to prostate cancer. Some had walnuts added to their grain for two months. Researcher Paul Davis told an American Chemical Society conference: 'We found that walnut feeding resulted in smaller, slower-growing tumours. 'Walnuts should be part of a balanced diet that includes lots of fruits and vegetables.' Dr Helen Rippon, of the Prostate Cancer Charity, said: 'It is far too early to say whether walnuts can prevent prostate cancer in men as well as in genetically modified mice. 'Nonetheless, dietary modification is of great interest in prostate cancer prevention, particularly as it involves men taking action to support their own health.'