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Last Updated: Monday, 3 December 2007, 13:26 GMT
Should we listen to cancer scare stories?
Innes Bowen
Series Producer, More or Less, BBC Radio 4

Red meat
Red meat has been linked to cancer
Giving up smoking is a good idea if you want to avoid cancer. But is it worth giving up anything else?

In the past few weeks alone we have been warned of the potentially carcinogenic qualities of coffee, alcohol, red meat and bacon.

The latest dietary 'bad boy' under the spotlight is fried food - apparently a risk for ovarian and womb cancer.

The media keeps us supplied us with a steady stream of these stories.

But among some specialist journalists there is a growing scepticism.

We cannot predict at the level of individuals what the benefit will be
Professor David Shuker
World Cancer Research Fund

Michael Hanlon, the Daily Mail's science editor, said he has no intention of giving up any of the foods identified as risky - despite the fact that his own newspaper has carried plenty cancer warnings over the years.

On Radio 4's numbers programme More or Less, he challenged cancer expert Professor David Shuker to tell him how many months or years he might add to his life by following the World Cancer Research Fund's recent advice to limit red meat intake and avoid processed meats altogether.

"There are a few years to be gained by following this advice," according to Professor Shuker, an adviser to the WCRF expert panel member.

"But we cannot predict at the level of individuals what the benefit will be. We can only advise individuals how to join the group that has a lower risk."

'Worth the effort'

Joining that low risk group is worth the lifestyle changes in Professor Shuker's view, even if the benefits are not clear at an individual level.

He said red meat and processed meat were associated with bowel cancer - "a pretty nasty disease to have and you don't want to get it".

Hanlon is convinced that there are significant health benefits associated with giving up smoking, but he is not convinced the same applies to giving up certain foods.

Ben Goldacre, the medical doctor behind the Guardian newspaper's Bad Science column agrees that there is a vast difference between the link between smoking and lung cancer and the links between certain foods and cancer.

He believes that epidemiologists - the scientists who study factors that influence the occurrence of disease - were emboldened by the discovery by Sir Richard Doll in the 1950s of the strong link between lung cancer and smoking.

There was an expectation that epidemiology would produce many similar breakthrough discoveries.

Diet seemed to be a likely cause of cancer, but Goldacre has written in his column, "beyond the most basic sensible dietary advice, and despite some promising early leads, the evidence simply didn't back up any of the more specific culprits".

Sensible approach?

But although the links between certain foods and cancer are not as strong as those between smoking and cancer, are people like Hanlon really sensible to ignore them?

Most cancers are diseases of old age
Michael Hanlon
Daily Mail

Let's take one example of an allegedly risky food: processed meat.

Hanlon admits that regularly eating processed meat increases the risk of developing bowel cancer: The lifetime risk increases from one in 18 to between one in 15 and one in 16.

That means for every 100 people who follow Hanlon's lead and continue to eat processed meat, one additional person will get bowel cancer.

To many people this will seem like too big a risk to ignore.

Hanlon disagrees: "Most cancers are diseases of old age.

"Most people who live to 80 or 90 will have had some form of cancer."

He believes that by abstaining from certain foods throughout his entire life, he would probably add nothing to his current life expectancy of 80.

No simple tests

Professor Shuker would like to see more research done into the causes of cancer to enable doctors to identify individuals who have an increased level of risk.

But he said: "For most cancers, we don't have the kind of simple tests we can do for heart disease."

GPs can measure blood pressure and cholesterol levels and intervene with medications to help those identified as being at a high risk of heart disease.

But in most cases it remains difficult to predict who will and who will not get cancer.

The work of scientists like Professor Shuker indicates that if more people followed the dietary advice of organizations like the WCRF, millions of cancers could be avoided.

At a whole population level, the figures are impressive.

At an individual level however the statistics are less impressive - there is no guarantee that cancer will be avoided even by a lifetime of abstention.

For those unfortunate enough to get cancer, however, the benefits of treatment are tangible at an individual level.

The government's decision to improve services for those who already have the disease - outlined in its new Cancer Reform Strategy for England - is likely to be appreciated more than additional advice about how not to get ill in the first place.

  • More or Less, Radio 4's weekly look at the numbers behind stories in the news, is broadcast on Mondays at 16.30 GMT and is also available as a pod cast.



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