[The following is an exact transcript of this podcast.] 

You’ve no doubt heard that grapefruit juice can greatly increase the effects of some drugs. Even to a dangerous degree. Pharmacologist David Bailey made that discovery almost 20 years ago. A substance in the juice blocks an enzyme that breaks down the drugs. Now Bailey’s back with a fresh finding—grapefruit juice, orange juice, apple juice and other fruit juices can also severely decrease the absorption of certain drugs. He announced this discovery August 19th at the national meeting of the American Chemical Society in Philadelphia.

Some of the drugs that have their dosages effectively decreased by various juices include medications that fight heart disease, infection and even the rejection of transplants. Key ingredients in the juices appear to block a molecule that carries drugs from the small intestine into the bloodstream. So a lot of the medication gets flushed out without ever reaching its target. Bailey says, "This is just the tip of the iceberg.  I'm sure we'll find more and more drugs that are affected this way."  So when taking medications, a sip of H₂O is probably the way to go.

—Steve Mirsky 

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