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News Release

For immediate use

Oct. 27, 2004 -- No. 523

Fruits, vegetables may decrease some women’s risk
of specific type of breast cancer tumor, study finds

CHAPEL HILL -- A team of researchers led by epidemiologists at the University of North Carolina at Chapel Hill found that eating 35 or more servings of fruits and vegetables each week decreased postmenopausal women’s risk of a specific type of breast cancer tumor – estrogen-receptor positive – by 36 percent.

Estrogen-receptor positive tumors represent approximately 63 percent of breast cancer diagnoses.

The results came from an analysis of the dietary habits of women who participated in the Long Island Breast Cancer Study Project, a multidisciplinary, multi-institutional collaboration to identify environmental risk factors for the disease.

The Long Island study was funded by the National Cancer Institute and the National Institute of Environmental Health Sciences and includes more than 3,000 residents of New York’s Nassau and Suffolk counties.

The diet study is the first to examine the influence of diet on breast cancer by grouping women with breast cancer by estrogen and progesterone status, said Dr. Marilie Gammon, professor of epidemiology in UNC’s School of Public Health and the Long Island study’s principal investigator.

"By including these hormone status measurements, we are better able to identify women who would best benefit from eating lots of fruits and vegetables," she said. "However, what type of tumor a woman may be diagnosed with in the future is unknown. Therefore all women, particularly perimenopausal and postmenopausal women, should include five servings of fruits and vegetables in their diet each day since hormone-sensitive tumors are the most common tumors among American women."

Gammon also is a member of the UNC Lineberger Comprehensive Cancer Center and is deputy director of UNC’s Center for Environmental Health and Susceptibility.

Other investigators have shown that the international variation in breast cancer rates is most striking among postmenopausal women. The high rates of breast cancer found in Westernized countries, such as the United States, are due primarily to the large number of women with estrogen-receptor and progesterone-receptor positive tumors.

Thus, identification of specific foods that may help to reduce a woman’s chance of developing this type of breast cancer is an important public health finding, Gammon said.

Because the Long Island study sample size was so large, scientists were able to adequately consider whether association among intake of fruits, vegetables and antioxidants varied with menopausal status, or with clinical characteristics of the cases’ disease, including a joint measure of estrogen-receptor and progesterone-receptor status.

The reduced risk did not apply to premenopausal women. The study included data from 2,963 women: 1,463 breast cancer cases and 1,500 women without the disease. Women completed a food frequency questionnaire that included assessment of the frequency and portion size of 13 fruits and fruit juices and 16 vegetables and the use of multiple and single vitamin supplements.

Such results may help postmenopausal women decrease their risk of contracting the most common type of breast cancer, said Mia Gaudet, a doctoral student in the department of epidemiology and first author of the study.

"We know that eating more fruits and vegetables is an effective way to maintain good health for anyone," said Gaudet. "These findings can be particularly helpful to postmenopausal women looking for ways to decrease their risk of breast cancer."

Eating leafy green vegetables such as spinach or greens, and colorful vegetables such as carrots, squash, sweet potatoes, tomatoes or peppers can help since these foods are high in nutrients such as the carotenoids, lutein, lycopene and alpha and beta carotene.

"The more colors on your plate, the better," said Gaudet, "because the more colorful the fruit or vegetable, the more packed it is with nutrients."

Study results appeared in the September issue of Cancer Epidemiology Biomarkers & Prevention and are available at

Other study scientists are from the Mount Sinai School of Medicine, Stony Brook University’s School of Medicine, Pfizer Inc. and Columbia University.

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