Cancer rates would fall dramatically if people ate a healthier diet and made better lifestyle choices, according to a researcher, who also said scientists were learning more about the kinds of food which prevented cancers.
Prof Alan Conney, director of the Laboratory for Cancer Research at Rutgers University, was speaking yesterday in Washington DC on the potential of functional foods and "nutraceuticals" to reduce disease and improve health.
He said the use of foods in disease prevention dated back at least 1,000 years in medical texts recovered in China. The question was: "What is it in our diet that is protective?"
His main research was ways of preventing cancers by changing diet.
"Although a person's genetic make-up is an important cause of cancer . . . a big proportion of it is environmental and lifestyle-related," he said.
Studies suggested that between 70 per cent and 80 per cent of all cancers could be avoided by adopting a changed lifestyle, i.e. not smoking or avoiding too much sun. "About a third of cancers are related to dietary factors," he said.
It was known, for example, that there were health benefits in taking up to five servings a day of green/yellow vegetables and fruit, with a 40 per cent to 50 per cent reduced risk.
Other substances had also been shown in animal studies to reduce cancers. Tea could reduce cancer rates in mouse models, as could the herb rosemary and the chemical which produced the yellow colour in curry.
"We don't know if these chemicals are protective in humans, and that is the problem," he said.
More studies were needed because while a general population might benefit from a dietary choice, an individual within that group might see no benefit, or might even be at greater risk, by pursuing that choice.
"We need to understand the mechanisms of cancer," he said.
Prof Paul Lachance, executive director of the Nutraceuticals Institute at Rutgers, described the work of his institute.
He said nutraceuticals were foods that had substances which could reduce disease risk or give some health benefit. They came in various forms, including dietary supplements, natural functional foods, such as garlic, or foods which had been fortified. Foods contained thousands of chemicals.
He said the flavonoids in tea had been shown to provide a health benefit in tests, but there were at least 4,000 different versions of this chemical and little was known about them.
"We are a pill culture and we are always looking for that golden pill," he said.
He said the benefits of nutraceuticals would not help the 80 per cent of US people who made bad dietary choices.
