Doubling fruit, veggie intake doesnt reduce breast cancer recurrence risk

Eating double the amount of fruits and vegetables than recommended in their diet will not reduce the risk of breast cancer recurrence for those women whose cancers were diagnosed and treated at an early stage.

Washington, July 18 : Eating double the amount of fruits and vegetables than recommended in their diet will not reduce the risk of breast cancer recurrence for those women whose cancers were diagnosed and treated at an early stage.

The National Cancer Institute has set '5-a-day' dietary goals for women recovering from the disease, and experts conducting a new study have found that eating more than this does not reduce the risk of the disease's recurrence.

The multicenter study was led by John Pierce, PhD, a professor at the Moores Cancer Center at the University of California-San Diego.

In addition to Stanford and UCSD, the other sites participating in the Women's Health Eating and Living trial were the University of California-Davis, M.D. Anderson Cancer Center in Houston, the University of Arizona and Kaiser Permanente in Oakland, California, and in Portland, Oregon.

As a part of the study the researchers documented the effect of diet on nearly 3,100 women previously treated for early-stage breast cancer.

Half of the women were randomly assigned to follow the dietary guidelines from the NCI and the U.S. Department of Agriculture that promote eating five servings of fruits and vegetables daily. The other half were asked to eat almost double that amount of vegetables and fruits while reducing their fat intake.

National guidelines call for eating five daily servings of fruits and vegetables, 20 grams of fiber and getting less than 30 percent of their calories from fat.

Women assigned to the intervention group were asked to limit the amount of fat in their diet to 15-20 percent of their total calories. In addition, they were expected to consume five servings of vegetables plus 16 oz. of vegetable juice, three servings of fruit and 30 grams of fiber on a daily basis.

Researchers recruited women who had been diagnosed with early stage breast cancer while they were between the ages of 18 and 70, and who had successfully completed treatment for the disease.

After following the women for an average of 7.3 years, the researchers found that the breast cancer recurrence and mortality rates were nearly identical for both groups of women.

"For breast cancer survivors who are meeting the '5-a-day' dietary goals set by the National Cancer Institute, there is no benefit to further increasing their vegetable and fiber intake in terms of preventing breast cancer recurrence," said Marcia Stefanick, PhD, professor of medicine at the Stanford Prevention Research Center and the senior author of the study.

"I was really surprised and, frankly, a little disappointed by the results. We expected the two-fold increase in vegetables and fruits, plus the increased fiber and reduced fat to make a difference in the recurrence rates," Stefanick said.

Although the recurrence rates for both groups were the same, the rate for the control group was much lower than the researchers expected at the outset. About 17 percent of the women in both groups had a recurrence of breast cancer during the course of the study, compared with the 30 percent researchers anticipated in the control group, based on previous studies.

However, Stefanick warns that the results of the study don't mean that women who have been diagnosed with the disease stop eating the recommended daily diet.

"I would certainly hope that people don't interpret these results as evidence that eating a lot of vegetables doesn't make a difference in breast cancer. What it shows is that getting more than the recommended amounts doesn't change the recurrence rate for women who have already completed treatment for early-stage breast cancer," she said.

The notion that eating more fruits and vegetables might stave off cancer stems from animal studies showing that plant-derived foods contain anti-carcinogens. There have also been studies indicating that high-fat diets may be linked to an increased risk for cancer. But the association between diet and cancer in humans is not definitive.

The study will be published in the July 18 issue of the Journal of the American Medical Association.

ANI