Prostate cancer kills 10,000 men a year in Britain and affects one man in three eventually. But while this can be a devastating disease, if often has little effect on a man's longevity and men can be asymptomatic for many years. In recognition of this, for the first time, the guidelines published at the end of February by the National Institute for Health and Clinical Excellence (NICE) advocate active surveillance for men with low-risk, localized prostate cancer who are considered suitable for radical treatment.

Over the past ten to 15 years, there have been a number of significant advances in prostate cancer management but also differing views on the most effective treatments. While men with early-stage disease are being offered the option of active surveillance, is there any evidence that we could prevent the disease occurring in the first place or at least halt its progression?

There is some evidence that being overweight has an indirect effect on the risk of developing prostate cancer because the extra blood volume produced in obesity can interfere with PSA testing, according to a study published in The Journal of the American Medical Association.

Eating adequate amounts of fruit and vegetables may be beneficial in reducing the risk of developing prostate cancer, especially cruciferous varieties such as sprouts. A study also reported that consuming two servings of tomato sauce each week appears to significantly reduce the risk of developing prostate cancer, probably because of the antioxidant effect of lycopene. However, an EPIC study conducted in the 1990s found that there was no apparent association between consumption of fruit and vegetables and prostate cancer incidence.

Polyphenois and isoflavones are nutrients in food that are currently the subject of much research. One study has shown a reduced incidence of prostate cancer in Asian men living in Asia, compared to Asian men living in America. However, this benefit disappears in Asians who have lived in the US for more then ten years; and ethnic Asian diet, which has high levels of polyphenols and isoflavones, may confer the protective effect.

There is also evidence that vitamin E and beta carotene supplements can be beneficial to men who normally have low intakes in their diets. Vitamin E can reduce the risk of contracting prostate cancer by 32 per cent and delay its progression by 41 per cent; the effect of beta carotene was not so obvious.

So, what is the best dietary advice for a man once he has received a diagnosis of prostate cancer? Should he adapt his diet in any way to improve his survival and chance of a cure? The current evidence clearly advises that the best way to keep nutritionally fit is to consume a balanced diet: a balance between protein, fat, carbohydrate, vitamins, and minerals, which are provided by eating regularly and in moderation. There are no 'bad' foods per se. Rather, it is the quantities consumed of these foods that can cause imbalance in the diet and harm.

Many men will remain healthy for many years once diagnosed with prostate cancer. But if the illness progresses, some may encounter nutritional problems brought about by advancing disease. Symptoms such as loss of appetite, nausea, vomiting and weight loss are significant issues that reduce quality of life and well-being. But all such symptoms can be managed if assistance is sought.