It is probably the most delicious cancer treatment yet devised. A recipe book built around foods known to help to fight prostate cancer is the first example of “evidence-based cooking”, its author said yesterday.

The Prostate Care Cookbook has been written by scientists for people with prostate cancer or at risk of developing it.

“There is growing scientific evidence that strongly suggests that diets rich in certain foods can help prevent this disease or its spread,” the authors write. “For those living with the condition, a controlled diet may be the only means of active treatment.”

Prostate cancer is the most common form of cancer in men, but aggressive treatments can often be worse than the disease, said Margaret Rayman, Professor of Nutritional Medicine at the University of Surrey and lead author of the book.

“It’s often quite indolent and slow-growing. So there may be something you can do with diet.” Foods such as onions and garlic, broccoli and cauliflower, fish and tomatoes, have all been shown to lower the risk of developing the cancer, or slowing its spread.

But Professor Rayman said: “It’s not just what you eat but how you cook it.” When garlic or onions are chopped, they produce an enzyme, alliinase, that produces anti-cancer compounds. But these are destroyed if they are heated immediately.

“The secret is you’ve got to leave the vegetables to stand for ten minutes before cooking to allow the alliinase to do its work,” Professor Rayman told the British Science Festival.

Cruciferous vegetables, which include broccoli, cabbage, rocket and radish, also need to be chopped but not overcooked. “Cook them lightly, steam them or eat them raw,” Professor Rayman advised.

Tomatoes are also best chopped or processed, and she said “a sauce made from a tin of plum tomatoes would be ideal”.

Chefs including Raymond Blanc and Antony Worrall Thompson have contributed recipes to the cookbook, which has been produced in association with the charity Prostate Cancer Research Foundation.

Professor Rayman said that her aim was to offer “food that everyone in the family can eat, not something precious”.

The recipes also aim to avoid foods that may worsen risks for prostate cancer, including dairy products, processed or overcooked meats and saturated fats.

There is no need to cut out milk in your tea, Professor Rayman say, but “you shouldn’t be pigging out on milk or yoghurt”.

Every year 35,000 men in Britain have prostate cancer diagnosed, and the condition accounts for 22 per cent of all cancers. However it is responsible for only 12 per cent of cancer deaths in men, and in older patients doctors often recommend “watchful waiting” rather than radical surgery, which can have serious side-effects including erectile dysfunction.

Managing such patients’ diet more effectively will allow them to take control of their treatment, Professor Rayman said.

“There’s also a psychological benefit to doing something about your own condition,” she added.

Roasted tomato and sweet potato soup (Serves 4) 450g sweet potatoes, peeled and sliced 1.2kg tomatoes, halved Two tablespoons olive oil One large onion, chopped into wedges Two garlic cloves, sliced Salt and pepper One small bunch of basil leaves, torn, plus extra to garnish One tablespoon of tomato puree

1 Preheat the oven to 200C/400F/gas 6

2 Parboil the sweet potatoes in a saucepan for five minutes, drain and leave to cool

3 Place all the ingredients except the tomato puree on a roasting tray and drizzle with the oil

4 Roast in the oven for 30 minutes, turning the vegetables halfway through

5 Once removed from the oven, pick any burnt skins off the tomatoes, which will come away easily

6 Whizz all the ingredients, along with 600ml water and the tomato puree, in a blender or processor

7 Reheat to serve and garnish with basil leaves

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