The Lancet reported last week that a "constellation of potential risk factors" had almost cost a woman in Olympia, Washington her leg.  Dr. Lucinda Grande reported that the woman had started a "grapefruit diet", while taking birth control pills and having a previously undiagnosed genetic condition, while remaining immobile in her car for an extended period.  The result of this "perfect storm" of bad facts was a blood clot that eventually turned her left leg purple.  Not just an ordinary blood clot, according to the BBC:

When doctors examined her, an ultrasound scan confirmed the woman had a large blood clot within the veins of her left leg, which stretched from her hip down to her calf and she was deemed to be at risk of losing her leg because of gangrene.

The culprit, according to the Lancet article, is apparently the grapefruit.  The woman had not previously eaten much grapefruit, but had eaten about a half pound a day for three days.  Whatever the weight-loss advantages of the grapefruit diet, one of the effects of eating a lot of grapefruit is that is changes the effects of certain drugs.  In this case, it may have stopped a key enzyme from breaking down the estrogen from her birth control pills.  Combined with her genetic predisposition, the clot may have resulted.

It has been reported previously that grapefruit or grapefruit juice has an effect on other drugs.  It apparently enhances the effects of some, like certain antihistamines, and diminshes the effects of others, like Viagra.  The Mayo Clinic has a specific list:  Other studies have indicated no effect despite indications from others, such as with caffeine.  The evidence in many cases is inconsequential and subject to interpretation

I happen to love grapefruit and have drunk grapefruit juice for breakfast for years.  I don’t drink caffeine with breakfast, but I do take over-the-counter antihistamines.  My doctor has told me not to worry about any side effects.  She did warn that if I took statins, we might have to rethink this.  Grapefruit is a good source of Vitamin C

Grapefruit growers should not have to worry about liability from the natural effects of grapefruit or the interactions between it and drugs.  This is quite similar to the naturally occurring mercury in tuna; courts are not eager to find liability for someone growing or selling an unadulterated, legal product in a safe manner. 

In other news, a horse named The Pamplemousse was scratched from the Santa Anita Derby over the weekend.  He won’t be competing in the Kentucky Derby, either.  What does "Pamplemousse" mean in French?  Grapefruit.