Among fruit juices, grapefruit has the strongest effect, but lime juice and orange juice made from Seville oranges similarly inhibit the CYP 3A4 enzyme. With some drugs, apple juice may interact in the same way.
Posted on 03/21/2006 11:20:30 PM PST by neverdem
In 1989, a group of Canadian researchers studying a blood pressure drug were astonished to discover that drinking a glass of grapefruit juice dangerously increased the drug's potency.
They were testing the effects of drinking alcohol on a medicine called Plendil. The scientists needed something that would hide the taste of alcohol so that subjects would know only that they were taking the drug and not know whether they were drinking alcohol with it.
"One Saturday night, my wife and I tested everything in the refrigerator," said David G. Bailey, a research scientist at the London Health Sciences Center in London, Ontario, and the lead author on the study. "The only thing that covered the taste was grapefruit juice."
So they used it in their experiment, expecting the grapefruit juice to be irrelevant to their results. But blood levels of the drug went up significantly in the control group that drank just grapefruit juice, without alcohol.
"People didn't believe us," Dr. Bailey said. "They thought it was a joke. We had trouble getting it published in a major medical journal."
Eventually the paper was accepted and published by Lancet, in February 1991.
Finding why juice had that effect was the next question.
The answer, it turned out, lay in a family of enzymes called the cytochrome P-450 system, in particular one known as CYP 3A4. This enzyme metabolizes many drugs, and toxins as well, into substances that are less potent or more easily excreted or both.
Grapefruit juice interferes with the ability of CYP 3A4 to do that, increasing...
(Excerpt) Read more at nytimes.com ...
I love grapefruit juice, it's too bad it is not sold in frozen concentrate around here. I have not seen it in 3 years. The Ocean Spray in bottles is too expensive.
is that a grapefruit in your pocket or are you happy to see me? doh! :)
How old is this chart/table/whatever? Baycol has been removed from the market since about 2002, because it kills people(Bayer Co.).
Make that August 8, 2001.
They are considered useful in several weight-loss diets.
I am not a medical person, but I think that a daily grapefruit might help prevent kidney stones, but would be a slow "cure" for existing stones.
Interesting, anyone else heard of that? I could see where my grandmother would have forced herself to perhaps eat it herself to make him stay with it in hid diet. That could make sense, thanks! Just seems so tart when I try them, that I never got the attraction for breakfast.
Grapefruit juice is a diuretic - promotes urine flow. For that reason as well as being slightly acidic it would help prevent kidney stones.
Wow, I guess I'm glad I mentioned my grand dad's ailment in my post.
Seems the kidney stones were the issue for them.
I am a big fan of grapefruit for general health. You grandparents were certainly on to something. Try researching Grapefruit Seed Extract. I've been taking it twice a day for six years now. The stuff is great but fresh grapefruit with the seeds and rind ground up is the best. I've also used it as a topical anti-baterial for cuts, burns, infections, athletes foot, even a tarantula bite. I make a paste then apply that to the infected area a few times a day or under a bandage. The longest I've ever had to use it topically was 3 days.
Ask the NY Times. What does that have to do with the interaction of gut CYP 3A4 and other drugs taken by mouth with grapefruit and juices which were mentioned?
Actually try WalMart, that is the cheapest place to get the Ocean Spray juice.
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For that matter Seldane is out of the US market too. (Overly high doses of Seldane can stop the heart.)
The science is legit here. They're teaching us this in med school.
The reason that everyone reacts to drugs differently is precisely because of these Cytochrome P450 enzymes. Drug companies will abandon a drug that interacts with certain Cyt.P450s because there is a huge variation in how people will respond to them. Some will overdose on just a very small quantity and others will require monstrous doses to have any effect. The more active your particular enzyme, the larger the dose of the drug you're going to need. The less active, naturally, the smaller the dose. Listen to your body; it will tell you what's going on.
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