Phew! Good News About Grapefruit and Breast Cancer

It's become one of those emails that people seem to forward obsessively, along with the ones about waking up with a kidney missing and anti-perspirants leading to breast cancer (there's no proof of that, either). Except this one was true: almost a year ago there appeared a study in the British Journal of Cancer that seemed to link eating more than 1/4 of a grapefruit each day to an increased incidence of breast cancer. A lot of women we know - patients and colleagues among them - quit eating grapefruit completely.

Good news! Recently another study appeared in the British Journal of Cancer (2008;98(1):240-41) with completely different conclusions.

The authors of this study made use of information gathered during the Nurses' Health Study, a large-scale, long-term study which has been following the lives of thousands of women in the United States since 1976. (This is a much larger study than the one I reported on last year.) Starting in the mid 1980's, the participating women reported on their diet every four years. Questions included information about their consumption of grapefruit.

The researchers analyzed the diets of those women in the study who were diagnosed with breast cancer and found no link between grapefruit intake and incidence of breast cancer. This was true regardless of their Body Mass Index, whether they smoked, or other variables.

What's especially interesting is that when they split those women with breast cancer between those women who were on hormone replacement therapy and those who were not, they found that eating more grapefruit (at least 1/4 grapefruit or more per day, on average) was related to a reduced risk of breast cancer in those women who had never been on hormone replacement therapy.

The scientists further note in their report that for those women whose cancers were estrogen and progesterone negative, an increased consumption of grapefruit (the fruit, not the juice) was also related to a reduced risk of breast cancer.

What this means for you

When the older study was published, I had advised those women at an increased risk of breast cancer to consider cutting back on eating grapefruit or drinking grapefruit juice. This newer study, however, indicates just the opposite—it may even help you avoid breast cancer. If you've stopped eating grapefruit because of the earlier study, consider this your permission to start again. Enjoy!

First posted: July 23, 2008