Diet could cut cancer ratesFebruary 26, 2009
THE CANADIAN PRESS
A huge proportion of many common cancers could be prevented through diet, exercise and healthy weight maintenance, but it will take co-ordinated efforts by all sectors of society to reduce the burden of cancer worldwide, a sweeping international report says.
The report by the American Institute for Cancer Research and the World Cancer Research Fund, released Thursday in London, makes dozens of recommendations for governments, public health organizations, schools and industry that would help support individuals' efforts to cut their risk of developing the disease.
Those recommendations include government-mandated walking and cycling paths that encourage physical activity, policies that support the supply of well-priced, healthier food choices for consumers and schools providing built-in exercise opportunities for children.
"The report is saying that there is overwhelming evidence that diet and nutritional factors are related to cancer causation," said Dr. Shiriki Kumanyika, a professor of epidemiology at the University of Pennsylvania and one of 23 international cancer experts who penned the report.
"This report actually starts the process of doing something about it at a serious level," she said Wednesday from Philadelphia.
The document is a followup to an October 2007 report by the two groups that laid out how eating certain foods, being overweight or obese and having a sedentary lifestyle contribute to the development of a number of cancers.
While that message for individuals bears repeating "over and over," said Kumanyika, such lifestyle changes can be difficult to achieve and maintain – and require support by other sectors of society.
She said the report makes a strong case for other actors in society "that don't think they have anything to do with public health – they think that's the building down the street – to understand that every decision they make affects infrastructure where people live, which then affects how they walk, how they eat, where you put the store."
"There are a lot of decisions at different levels of different sectors that are actually influencing cancer prevention."
Commenting on the report, Heather Logan of the Canadian Cancer Society said a number of reports over the years have talked about what people can do to cut their risk of cancer.
"What this does is marry individual choice and public policy – and that's really important," said the society's director of cancer control policy, noting that a meeting in Halifax next month will bring together experts to evaluate the report in a Canadian context.
Kristan Aronson, a cancer epidemiologist at Queen's University, said this report is different than others because it doesn't just repeat what might seem the same old message.
"So we've heard before that you and I should probably drink less alcohol and exercise more and not be obese and maintain a healthy weight, etcetera," she said from Kingston, Ont. "But that has been directed at the individual level."
"This is much more far-reaching than in the past, saying that we're recognizing that all of us may be relatively weak when it comes to individual efforts, but if we're all encouraged as a society and if the governments are required to put in walking and cycling routes ... it's going to make things easier for people like us who are struggling with a job and kids and everything else."
"And (it says) governments should encourage healthy food – and discourage unhealthy food – through legislation and pricing. Oh my God, that's huge."
If the recommendations aren't acted on, the prognosis could be grim, Kumanyika predicted.
"If low-income countries continue to aspire to things that are considered fashionable and a sign of wealth or success, then we're going to see in huge populations throughout the world, a rise in cancer," she said.
"In countries like the U.S. and Canada, we're going to see more cancer."
The report includes prevention estimates for many types of cancer in the United States, the United Kingdom, China and Brazil.
About 45 per cent of colon cancer and 38 per cent of breast cancer cases in the U.S. could be prevented through eating healthy foods, keeping active and staying trim.
That three-pronged approach would prevent, for instance, 75 per cent of esophageal cancer in the U.K., 52 per cent of endometrial cancer in Brazil and one-third of stomach cancers in China.
In fact, the report found that one-quarter to one-third of all global cancer cases are related to diet, body weight and physical activity levels. The use of tobacco, which was not dealt with in this report, accounts for another third of all cancers worldwide and remains the Number 1 preventable cause of the disease.
Dr. Tim Byers, a professor in the school of public health at the University of Colorado, said one thing that surprised him is how ``global" the nutritional risk factors for cancer have become.
"A lot of these factors that we tend to stereotype as being only factors relevant in North America or in Europe are really increasingly relevant globally," Byers, one of the report's authors, said from Denver.
"People (in developing countries) are beginning to get fat and sedentary just like, unfortunately, we've been used to ourselves in North America for a long time."
"If we don't take advantage of improving our nutritional risk factors for cancer, we're always going to be swimming upstream. We're never going to achieve the kinds of improvements and the kinds of declines in death rates that are truly possible."
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