Women in the study who ate the recommended five servings or more a day of vegetables and fruits and exercised moderately cut their risk of death in half, according to the study authors.
The benefits were seen both in obese and normal-weight women.
Moderate exercise was defined as the equivalent of taking a brisk, 30-minute walk a day, six days a week.
“Even in the women who were overweight, the combination of a fruit and vegetable-based diet and exercise lowered their risk of dying from breast cancer by 50%,” researcher John Pierce, PhD, tells WebMD.
Combination Was Key
Studies examining the impact of diet or exercise on breast cancer survival have been mixed, with some suggesting a benefit and others finding little evidence of an association.
Three to five hours of moderate exercise a week were was associated with a 50% reduction in the risk of dying from breast cancer in a study from Harvard Medical School, reported in 2005.
The new study by Pierce and colleagues from the University of California, San Diego, is the first to look at the combination of physical activity and diet on breastcancer survival.
The study included 1,490 women with early-stage breastcancer who were participants in a larger trial examining diet and breast cancer survival.
None of the women were told what to eat or how much to exercise, but they all were interviewed about their diets and physical activity levels when they entered the study between 1991 and 2000.
They were then followed for an average of 6.7 years.
About half as many obese women as lower-weight women reported eating five or more servings a day of fruits and vegetables and exercising regularly (16% vs. 30%).
But regardless of weight, women who ate the healthiest diets and exercised the most had roughly half as many breast cancer-related deaths during the follow-up period as the rest of the study population, including women who ate healthy diets but did not exercise regularly and women who exercised but didn’t eat five or more servings of fruits and vegetables a day.
The study appears in the June 10 issue of the Journal of Clinical Oncology.