By FIONA MACRAE

Last updated at 09:58 31 March 2008

Just one sausage a day could dramatically increase the risk of bowel cancer, experts say (picture posed by model)

One sausage a day can significantly raise the risk of bowel cancer, one of the deadliest forms of the disease, experts have warned.

Eating 1.8oz (50g) of processed meat a day - the equivalent of one sausage or three rashers of bacon - raises the likelihood of the cancer by a fifth, research shows.

The sobering statistic adds to growing evidence that too much meat in the diet can be deadly.

Bowel cancer claims 16,000 lives a year in Britain, with lung cancer the only form of the disease which kills more.

However, fewer than one in three Britons is aware of the danger posed by favourite foods such as bacon and sausages, the World Cancer Research Fund warned.

Professor Martin Wiseman, the charity's medical and scientific adviser, said: "We are more sure now than ever before that eating processed meat increases your risk of bowel cancer and this is why WCRF recommends that people avoid eating it.

"The evidence is that whether you are talking about bacon, ham or pastrami, the safest amount to eat is none at all.

"When you consider that eating 50g of processed meat a day can increase your risk of bowel cancer by about a fifth, it is clear that you can make a positive difference by cutting out as much as possible."

Processed meats - those preserved by smoking, salting and any other method apart from freezing - include bacon, ham, pastrami, salami and hot dogs.

Sausages, hamburgers and mince fall into the bracket if they have been preserved with salt or chemical additives.

Those who can't bear to cut out processed meats will still benefit from eating smaller quantities, said Professor Wiseman.

"We do recommend that people avoid it completely, but it is not a case of all or nothing," he added.

"Cutting down the amount of processed meat you eat can also reduce your risk of developing bowel cancer.

"But we need to do more to get this message across because if two-thirds of people don't know about the link between processed meat and bowel cancer, then they are not in a position to be able to make informed decisions about whether to eat it or not."

A survey of 2,000 Britons carried out for the World Cancer Research Fund ahead of the start of Bowel Cancer Awareness month tomorrow found that only 30 per cent were aware of processed meat's role in the disease.

The poll follows a landmark report from the charity last year which blamed putting on weight, drinking and a whole range of everyday foods, including processed meats, for causing cancer.

Among the findings of the analysis of thousands of studies on lifestyle and cancer was that small amounts of processed meat raise the risk of bowel cancer by 20 per cent.

Processed meats may also trigger cancer in the prostate, lung, stomach and oesophagus.

The analysis, published last November, also found that red meat raises the risk of the disease, but to a lesser extent.

Both types of meat can be high in fat and iron, both of which are linked to cancer.

However, processing raises levels of cancer-causing chemicals called N-nitroso compounds, making bacon, sausages and the like more deadly.

It is estimated that if everyone cut down on red and processed meat, one in ten cases of bowel cancer could be prevented.

The charity's warning coincides with the discovery of three genetic flaws behind bowel cancer, taking the number of known mutations to seven.

Pinpointing more rogue genes could lead to the development of a genetic test for the disease.

Edinburgh University researcher Professor Malcolm Dunlop said: "It is important to catch bowel cancer at an early stage when it is more likely to be treated successfully."

Three steaks a week - but no more

Meat is a good source of protein as well as vitamins B and D and minerals such as iron and zinc.

However, these benefits have to be balanced against increasing evidence that red and processed meats raise the risk of cancers including bowel cancer.

Experts say red meat need not be eaten every day and that 18oz (500g) a week in cooked weight (or 27oz/750g uncooked weight) is sufficient.

That is the equivalent of three steaks, although the definition of red meat covers pork and lamb as well as beef.

Processed meat's stronger links to bowel cancer have led to advice that it should be avoided altogether.

The World Cancer Research Fund advises that any meat bought should be as lean as possible, with any visible fat trimmed before cooking.

Fish, low-fat poultry and plant sources of protein such as beans or lentils are convenient and healthy alternatives to red meat.

When making a chilli with mince, the quantity of meat can be halved and extra kidney beans added in its place.

Chops or sausages can be swapped for fish, with a chicken or tuna sandwich providing a healthy alternative to bacon.

Diets rich in fish and fibre-loaded fruit and vegetables may also cut the risk of the cancer, as could cutting down on alcohol, exercising more and losing weight.

Bowel cancer is one of the most easily treated cancers if caught early.

However, embarrassment over discussing tell-tale signs such as diarrhoea or rectal bleeding leads to thousands of victims a year not seeking help until it is too late.

The disease is most prevalent in the over-60s and is slightly more common in women than men.

Women have a one in 18 risk of bowel cancer in their lifetime, while for men the figure is one in 20.