柑橘好，但是西柚(grapefruit)可能會提高乳腺癌發病率30% ZT

Researchers at the University of Southern California followed the women from 1993 to 2002. When they analyzed their data, they found that those who ate the most grapefruit (about one quarter per day or half a grapefruit every other day) had a 30 percent higher risk of breast cancer than women who ate no grapefruit. This risk did not change even after researchers controlled for such factors as weight, family history of breast cancer, and use of hormone replacement therapy after menopause.

The investigators noted that estrogen (the hormone that promotes most breast cancers) interacts with grapefruit and that at least two earlier studies found higher levels of estrogen in women who eat a lot of grapefruit or drink a lot of grapefruit juice. This is such a well known effect that the FDA requires hormone replacement products to carry a label warning that grapefruit juice may increase their potency. We also know that grapefruit increases the potency of some other prescription drugs.

It's much too soon to conclude that grapefruit and grapefruit juice increase the risk of breast cancer. We need to know how long grapefruit's effects on estrogen last in the body, whether grapefruit itself or grapefruit juice is responsible for the change and what effects grapefruit and grapefruit juice have in premenopausal women. In the meantime, if you're worried, you might want to substitute other citrus fruits for grapefruit.

Andrew Weil, M.D.