Surprisingly Entertaining Article of the Day

Grapefruit juice. In the list of “things to talk about at a dinner party,” it comes just after raisins and just before ocular disease.Free Image Hosting at

But in today’s New York Times, an article promises to reveal the Secret Powers of Grapefruit Juice, so I immediately read through, hoping to stumble across invisibility, or maybe the power to turn ordinary permanent markers into the kind that smell nice. It turned out to be nothing so exotic, but still interesting, if not a little dated. The gist is that in the early ’90s, researchers discovered that the juice interacts with certain medicines in crazy ways, which could pose a danger to some patients.

What makes this simple idea stand out is that it’s a very good example of how science works. It starts with an experimental drug being tested on patients. Researchers needed to find out how alcohol interacts with the drug, so they set up a double-blind experiment. For those of you who are new to science, this just means that they needed to give some patients just the drug, some patients just the alcohol, and other patients the drug plus alcohol so they could isolate what it is that the alcohol does. However, the patients can’t know which they’re getting, since that could skew the results. So, the scientists needed to figure out a way to give people alcohol without them knowing they were getting alcohol. From the article:

“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.”

Not a bad job, huh? Good old fashioned trial and error science. That was interesting factoid #1: science is fun!

“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.”

And that is interesting factoid #2. A lot of peddlers of junk pseudoscience like to say that the scientific community just isn’t ready for their big, crazy idea. Here’s a good example of something that seemed crazy — simple fruit juice having such a big effect. I’m guessing that Dr. Bailey’s research was subject to some pretty close inspection, and if he had screwed up on the blinding or fudged some numbers, the study would have been tossed. But the results held up and were probably corroborated by further testing, and now the idea is well-accepted.Free Image Hosting at

So the researchers noticed something they hadn’t expected — the grapefruit juice had a huge impact on how patients processed the drug. They took this new info and used it to explore exactly what the effect was and why it happened. An accidental discovery quickly led to new research that saved lives, since they can now warn people not to mix grapefruit juice with some medications. Interesting factoid #3.

Interesting factoid #4 is that they did not immediately declare grapefruit juice the new all-natural wonder drug to replace cholesterol-lowering drugs (the most common drugs found to increase in potency when combined with the juice). Instead, they performed more tests and found that:

“The problem is the unpredictability of the effect,” he said. “You can’t just lower your dose of Lipitor and increase your consumption of grapefruit juice. There’s no uniformity from one individual to another or from one bottle of grapefruit juice to the next.

This is a big problem with a lot of “natural” remedies: when taken in their natural state, you have no idea how much benefit you’ll get, if any at all. One of the things scientists do is figure out what in nature is helping us, strip away the stuff that isn’t helping us, and create a controlled dose that is as safe as possible.

So, bring this up at your next dinner party. Grapefruit juice has moved up as an interesting topic of conversation, to just after current trends in beachwear to just before the pros/cons of daylight savings time.

Oh, and I apologize for the above nearly pornographic photo of the grapefruit interior.

Rebecca Watson

Rebecca is a writer, speaker, YouTube personality, and unrepentant science nerd. In addition to founding and continuing to run Skepchick, she hosts Quiz-o-Tron, a monthly science-themed quiz show and podcast that pits comedians against nerds. There is an asteroid named in her honor. Twitter @rebeccawatson Mastodon Instagram @actuallyrebeccawatson TikTok @actuallyrebeccawatson YouTube @rebeccawatson BlueSky

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  1. On a related note, today's Quaker Instant Strawberry Oatmeal "Brain Teaser" is: "Why are grapefruits called grapefruits when they don't look or taste like grapes? . . . A: Because they grow in clusters that look sort of like bunches of grapes."

    I choose to see the correlation between today's blog and today's delicious brunch as a sign from God that I'm blessed, as is my oatmeal.

  2. I thought a double-blind study was one in which the researchers and the patients don't know whether they've administered (or have been administered) a placebo or a real drug. A blind study is one in which the researcher knows, but the patient doesn't.

  3. Jewel, of course you're correct . . . rereading, what I wrote doesn't make that very clear as I was just emphasizing the fact that the patients couldn't know which they were getting. Thanks.

  4. Hmm.. I didn't get to see the pornographic grapefruit, I don't think your image hoster likes me. :-(

    I was told years ago that grapefruit juice could enhance the effects of various antidepressants, to the point that if the patient made (or broke) a habit of daily imbibing, it could affect the needed dose.

  5. Grapefruit juice can be lethal when mixed with appropriate amounts of gin, and served in a salt rimmed glass….

  6. "Oh, and I apologize for the above nearly pornographic photo of the grapefruit interior. "

    No you don't.

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