The government study found no benefit from a diet that included far more than recommended servings of five fruits and vegetables a day.
The study appears in this week’s Journal of the American Association.
"It sends us back to the drawing board," said Susan M. Gapstur of the Feinberg School of Medicine at Northwestern University, who was not involved in the new study but was a writer of an accompanying editorial in The Journal.
"Should we really have focused on dietary components like fruits, vegetables and fat?" Dr. Gapstur asked. "Or should we be focusing, in addition to diet, on lifestyle factors including physical activity and weight."
For now, the message for the 2.4 million breast cancer survivors in the United States is that they do not need to go overboard on vegetables, researchers said.
Earlier research on whether a healthy diet prevents breast cancer has shown mixed results. The new study was designed to be more rigorous.
In this experiment, all the women has been successfully treated for early staged breast cancer. Their average age was 53 when the study began.
A group of 1,537 women were randomly assigned to a daily diet that included five vegetable servings, three fruit servings, 16 ounces of vegetable juice and 30 grams of fiber. In most cases, a serving equaled a half cup. French fries and iceberg lettuce could not be counted as vegetables.
The women were allowed to eat meat but were told to get more than 15percent to 20 percent of their calories from fat.
As a comparison, an additional 1.551 women were assigned to get educational materials about the importance of eating five servings of fruits and vegetables a day.
During the next seven years, the cancer return in about the same proportion of women in both groups. About ten percent of both groups died during that time, most of them from breast cancer.
source: Manila Bulletin
Health & Science