Researchers at the Harvard School of Public Health studied the diets of more than 83,000 women who entered the Nurses’ Health Study in 1980. By 1994, 2,697 of those women were diagnosed with breast cancer. One of the key findings was that premenopausal women who had an immediate family member with breast cancer, that consumed at least 5 servings of fruits and vegetables per day, had a 70% lower risk of developing breast cancer compared with those that consumed less than 2 servings per day. The interesting component of the study was that only premenopausal women with a family history were protected. A hypothesis presented by one of the researchers (Shumin Zhang) was that these women may have a higher requirement for the carotenoids in fruits and vegetables, since their cells may proliferate more, and carotenoids may inhibit cell proliferation.
Source: Journal of the National Cancer Institute, 91: 547,1999.