The Grapefruit Effect: Have Your Meds and Grapefruit Too

Posted on March 10, 2014

Here's how to have a grapefruit without keeling over dead.

by Liz Jackson

The ‘Grapefruit Effect’ or ‘Grapefruit Juice Effect’ refers to the interaction many medications have when taken within 24-72 hours of grapefruit consumption. After discovering a fruit from Trader Joe’s called a Minneola Tangelo, I was surprised to learn about the chemistry of this hybrid fruit.


The Minneola which is genetically 1/2 grapefruit and 1/2 tangerine does not produce ‘The Grapefruit Effect’. And this fact has absolutely blown my mind.

I couldn’t resist contacting Compound Interest about this phenomenon. My new friend ended up writing a fascinating post about the Chemistry of a Grapefruit. With his help, this is what I learned about ‘The Grapefruit Effect’:


The grapefruit contains compounds called furanocoumarins. When grapefruits are ingested, these f-words will slow down how quickly your body can break down certain medications. So when this happens a few times, the levels of these drugs reach toxic levels and you can poison yourself. I’m considering renaming ‘The Grapefruit Effect’ to  ‘Death by F’n Grapefruit’.

The most recent ‘Grapefruit Effect’ study was done by the Canadian Medical Association Journal. They found that there are at least 85 medications that interact with grapefruit. You can click on the link or you can just glance at this awesome infographic I made on Wordle.

Wordle Grapefruit Effect

You can be rest assured that none of these 85 medications will interact with a delicious Minneola Tangelo. Or any tangelo for that matter.

On the other hand, a pomelo, which is a hybrid of an orange and a grapefruit will produce ‘The Grapefruit Effect’. But get this (prepare yourselves, your mind will be blown) if you take a pomelo (1/2 orange and 1/2 grapefruit) and ask it to make sweet, sweet love with a grapefruit… their offspring (a pomelo tangelo) will not produce ‘The Grapefruit Effect’.

I asked Compound Interest if eating a Pomelo Tangelo would give me the flavor and nutrition equivalent of three-quarters of a grapefruit without any drug interactions. He said that while there are no drug interactions, he could not state definitively that the exact chemical composition would amount the taste and nutrition of 3/4 of a grapefruit. Well this is what he said:

“I suppose you could argue that you’d gain a lot of the same health benefits as you would with grapefruits. I can’t say I can state much more on that authoritatively, but as the exact chemical composition of the two will differ despite their close relation, I imagine it’d be hard to quantify definitively how many tangelos you’d need to eat to obtain the equivalent health benefits from a grapefruit.”

This is truly Fascinating Medicine. My mind is blown and I hope yours is too. Let’s raise our glasses of Pomelo Tangelo Mimosas and cheers to safe medication consumption! (Kidding, don’t do that)


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