MAKING CHANGES to the diet of normal-risk individuals could have a much greater impact on their health and life expectancy than screening for a single condition like colon cancer, according to a UK expert.
Professor of Medicine at Liverpool University, Jonathan Rhodes, said that a screening programme specifically targeting colon cancer won’t increase life expectancy more than four months and usually by only a half or a third of this.
“Many of the risk factors for colon cancer including high calorie intake, low intake of leafy green vegetables and lack of exercise are important risk factors for a lot of other cancers as well as for heart disease, stroke and diabetes. If we could persuade people to address their diet and lifestyle, it would potentially have a much bigger impact on mortality, increasing life expectancy by nearly a year,” he said.
The gastroenterologist will outline his views this evening at the annual De Pazzi lecture, hosted by the Alimentary Pharmabiotic Centre and the Department of Medicine at University College Cork.
“I think at the moment there is a tendency among the public and media to put an enormous amount of faith into screening with the expectation that people can carry on with their lifestyles in the hope that they will be protected by screening,” said Prof Rhodes.
“Although I do support screening programmes, their impact will never be enormous and we need to be doing more to encourage appropriate lifestyle changes.”
He is somewhat critical of the “five a day” fruit and vegetable message, pointing out that more scientific research is needed to find out exactly which foods protect against which specific diseases.
Along with his team in Liverpool, he is currently involved in researching the potential benefits of soluble fibre. Their recent findings that broccoli and plantain could reduce bouts of the painful bowel disorder, Crohn’s disease, were published in the British Medical Journal.
Cancer of the colon and rectum affects about 6 per cent of western populations and carries a mortality approaching 50 per cent. Approximately 20 per cent of colorectal cancer causation is due to genes and 80 per cent is due to environment, particularly diet.
Prof Rhodes said that while individuals with a strong family history of colorectal cancer were likely to benefit substantially from regular colonoscopic screening, the case for screening the “normal risk” population is less straightforward.
“Screening of stool samples for non-visible [‘occult’] blood reduces mortality from colorectal cancer by about 15 per cent and is cost-effective. Such screening is currently offered for all adults over 60 in England and Wales.
“It is undoubtedly saving some lives, but it is likely that most people greatly overestimate its likely impact on life expectancy,” he said.
