The team fed apples to rats over a six-week period, and the more apples the rats ate, the less likely they were to develop cancer. Rats that ate the human equivalent to six apples per day saw a 44 percent cancer rate reduction.
The lead researcher attributes the cancer risk reduction to antioxidants found in the fruit. Those chemicals have been shown in other studies to slow the growth of a number of types of cancer cells.
"Our findings suggest that consumers may gain more significant health benefits by eating more fruits and vegetables and whole grain foods than in consuming expensive dietary supplements, which do not contain the same array of balanced, complex components, the lead researcher said.
An apple a day can help keep breast cancer away, according to a study in rats by food scientists at Cornell University.
"We found that tumor incidence was reduced by 17, 39 and 44 percent in rats fed the human equivalent of one, three or six apples a day, respectively, over 24 weeks," says Rui Hai Liu, Cornell associate professor of food science and lead author of the study.
In an article in the journal Nature five years ago, Liu and his colleagues credited phytochemicals -- antioxidants -- in fresh apples with inhibiting human liver and colon cancer cell growth.
Antioxidants help prevent cancer by mopping up cell-damaging free radicals and inhibiting the production of reactive substances that could damage normal cells.
"Studies increasingly provide evidence that it is the additive and synergistic effects of the phytochemicals present in fruits and vegetables that are responsible for their potent antioxidant and anticancer activities," Liu says.
"Our findings suggest that consumers may gain more significant health benefits by eating more fruits and vegetables and whole grain foods than in consuming expensive dietary supplements, which do not contain the same array of balanced, complex components," says Liu.
"This balanced natural combination of phytochemicals present in fruits and vegetables cannot simply be mimicked by dietary supplements," he explains.
Says David R. Jacobs, professor in the Division of Epidemiology, School of Public Health, University of Minnesota: "Dr. Liu is in the forefront of a group of investigators, including myself, who find extensive evidence that extremely important health aspects of food work through the combination of substances that make up that food, a concept we call food synergy.
Risk of many chronic diseases in modern life appears to be reduced by whole foods, but not by isolated large doses of selected food compounds.
Dr. Liu's current work on apples and breast tumors in rats is a perfect example of this principle."