RECENT PIONEERING research into the cumulative results of cancer studies over the last 50 years reveals that changes in people’s nutrition and lifestyle can reduce the risk of cancer by 30 per cent.
While developed countries tend to have higher cancer rates, as a result of longer life, the ongoing research project into the relationship between nutrition, body weight, lifestyle and cancer shows that people and governments can actually help reduce the risks by encouraging a specific diet and physical activity.
Professor Elio Riboli and Dr Teresa Norat from Imperial College London presented these findings at the 11th Marianna Lordos Lecture last Friday at the Cyprus Institute of Neurology and Genetics.
The two are leading scientists in research projects related to the role of nutrition in cancer. They came to Cyprus to present the findings of research funded by the World Cancer Research Fund (WCRF) and American Institute for Cancer Research (AICR).
Norat explained what makes the project so important: “What we do is to collect all the scientific evidence from epidemiological studies on the relationship between diet, lifestyle, nutrition, body mass index, body weight and cancers. And we summarise the results from all those studies.
“Using statistical methods, we provide estimates of the overall association, and using this scientific evidence, experts can provide dietary recommendations for policy makers, the food industry and public in general,” she said.
In 1997, scientists collected and assessed decades of cancer research results from which they drew certain conclusions and issued recommendations for cancer prevention. They did the same ten years later.
But from 2007, a group of scientists based at Imperial College London have been working on the WCRF Continuous Update Project, which basically takes any new published research on cancer and adds it to the existing body of work.
Evidence on the association between nutrition, obesity, physical activity and cancer is computed and analysed continuously, allowing scientists to assess the cumulative results of thousands of studies from around the world dating from the 1960s to the continuous present.
The project is unique in terms of its scope and long-term funding for continuous scientific evaluation on what really helps prevent cancer. It is considered “the most important summary of existing evidence” on nutrition and cancer published so far, said Norat.
“We are currently updating continuously all the existing evidence published on an ongoing basis. We included all data in one database which is the most extensive existing databases on lifestyle and cancer,” she added.
The aim is to avoid “mixed messages” going to members of the public about what actually helps prevent cancer and what doesn’t.
“One of the problems regarding information to the public is that the results and messages are sometimes contradictory. Our aim is to produce periodically a summary of all the information to avoid this constant invasion of messages saying, ‘an apple is protective’ (against cancer) or ‘an apple is not protective’,” she said.
The researchers then take the average of results that are weighted by the size of each study. Most studies come from America and Europe, though other countries are contributing more and more to the database.
“There are fluctuations in science. Sometimes you find that A causes B, sometimes that A doesn’t cause B. But if you look at 50 studies, rather than one at a time, you can honestly say at the end that the majority of studies found that A causes or prevents B. It’s called cumulative scientific evidence,” said Riboli.
The media plays a weighty role in the mixed messages given out, often reporting on any new study saying one thing is good for you and the next day, another saying it’s bad. This ongoing project aims to provide a solid base of information which can positively influence the public’s understanding of what preventive measures to take.
The 2007 report made a number of recommendations on preventing cancer through physical activity, nutrition and maintaining body weight. “It’s estimated that approximately one third of the cancers in developed countries could be avoided if individuals adhere or follow those recommendations,” said Norat.
After four years of continuously updating the database with new research results, the findings of the team of scientists in London confirm and strengthen the recommendations issued in 2007.
And what are they?
It is recommended that one tries to be as lean as possible within the normal range of body weight; is physically active as part of everyday life; limits consumption of energy-dense foods and avoids sugary drinks; eats mostly foods of plant origin; limits their intake of red meat and avoids processed meat; limits alcoholic drinks; limits the consumption of salt and avoids mouldy cereals (grains) or pulses (legumes), and aims to meet their nutritional needs through diet alone.
Further special recommendations are for mothers to breastfeed and children to be breastfed, while cancer survivors are encouraged to follow the recommendations for cancer prevention.
While scientists emphasise the importance of not smoking and avoiding exposure to tobacco smoke, tobacco is not included in the research.
“We are now mainly working on physical activity, body weight and nutrition. But of course we understand the importance of avoiding tobacco smoking in prevention,” said Norat.
The recommendations refer to all cancers in general rather than specific recommendations for each cancer. The panel of experts chose to give general recommendations because individuals want to prevent any and all cancers.
Also, Norat added: “They have been systematically checked with recommendations for the prevention of other chronic diseases so they are consistent with other recommendations.”
Riboli noted the importance of general recommendations “because often you see things like ‘to prevent this cancer you should do this, to prevent that other disease do that’ but in the end you only have one life, one breakfast, one lunch and dinner.
“The idea is to move towards a healthy behaviour, healthy environment that maximises our chances of preventing chronic diseases, like cancer, cardiovascular disease, respiratory diseases, neurological diseases, which tend to occur from middle age to older age,” he said.
And the recommendations are not limited to individuals but to the food industry and governments too that play a massive role in formulating policies to provide populations with access to good food and areas for physical activity as well as allocating resources for prevention and not just treatment.
For more detailed information on the study and recommendations for reducing the risks of cancer, go to www.dietandcancerreport.org, and click on ‘Expert Report’.
