c0nc0rdance: Hopefully you know that GRAPEFRUIT JUICE can inhibit liver enzymes that break down the active ingredients in certain therapeutic drugs, which can result in DANGEROUS OVERDOSING with certain drugs. A few surprising insights 🧪:

Hopefully you know that GRAPEFRUIT JUICE can inhibit liver enzymes that break down the active ingredients in certain therapeutic drugs, which can result in DANGEROUS OVERDOSING with certain drugs. A few surprising insights 🧪:

1. This was only discovered in 1991, and mostly by accident. A Canadian team were studying the impact of alcohol consumption on a hypertension drug, Plendil, and needed a "mixer" base for the control (water) and treatment (alcohol) so they mixed both into grapefruit juice.

The bioavailability of Plendil was higher than expected in the study, in both arms, but lower in a water-only control group. That study (conducted in 1989, to clarify) led to this 1991 Lancet paper, but it wasn't well publicized until after more study. https://pubmed.ncbi.nlm.nih.gov/1671113/

Interaction of citrus juices with felodipine and nifedipine - PubMedpubmed.ncbi.nlm.nih.gov Six men with borderline hypertension took felodipine 5 mg with water, grapefruit juice, or orange juice. The mean felodipine bioavailability with grapefruit juice was 284 (range 164-469)% of that with...

2. Metabolism of almost every drug is affected to some degree. The polyphenols in grapefruit juice can strongly interfere with Cytochrome P450 enzymes in your liver, the same enzymes that can either *activate* a "pro-drug" or deactivate active compounds over time.

Everything from Tylenol to Viagra to birth control to caffeine have different pharmacokinetics in individuals for up to three days after drinking a glass of grapefruit juice.

3. It's not just grapefruit juice. All citrus plants can produce the types of furanocoumarin, and all citrus derives from genetic hybridization of three ancestral plant lineages. Grapefruit juice has the highest specific effect on certain enzyme, orange juice the lowest.

4. Grapefruit juice, indirectly, likely causes thousands of deaths every year in the US. People continue to take their medications with grapefruit juice, especially among the elderly, and the result can be an effective dose 10-20 times safe levels. Link to CBS News article about CMAJ warning:

Drinking grapefruit juice with some medications can be deadly, study warnswww.cbsnews.com Grapefruits, Seville oranges, limes and pomelos contain chemicals that may affect an increasing number of medications

On the bad old site I saw a literal Nobel laureate organic chemist, who had mentioned being on medication, raving about the pomelo his trainee brought him… who assured him his hometown’s varietal was lower in furanocoumarins.

Shit. I will have a lot to ask my doc next time.

Is this just fresh grapefruit juice, or does processed/bottled juice do it too? And what about THIS stuff, to which i'm hopelessly addicted? I remember asking my cardiologist about it & he wasn't sure, but for the (thankfully brief) time i was on Atorvastatin, i avoided it just in case

Proceed with caution! "Grapefruit marmalade and crystallized grapefruit peel contained similar amounts of FCs to 100% grapefruit juice, but FCs were not detected in pomelo (buntan) marmalade or crystallized iyokan peel." pubmed.ncbi.nlm.nih.gov/21532264/

[Furanocoumarins contents and cytochrome P450 3A (CYP3A) inhibitory activities of various processed fruit peel products: outflow of 6',7'-Dihydroxybergamottin during processing treatment of peel] - Pu...pubmed.ncbi.nlm.nih.gov Furanocoumarins (FCs) such as bergamottin (BG) and 6',7'-dihydroxybergamottin (DHBG) contained in grapefruits are known to be cytochrome P450 3A4 (CYP3A4) inhibitors. These are contained in larger qua...

Huh. Grapefruit's gotta be one of my top favourite fruits. i miss those really sour white ones you used to be able to get. I guess they've gotten rare outside of Florida & Texas because "the market" wants the ruby reds.

why does it have to be so damn delicious

So hypothetically, if you wanted a more long lasting edible, you take it with grapefruit juice?

Is the small intestine also a factor, beyond liver enzymes, or is the infographic just weird?

I think that's meant to be the whole gut: stomach to colon, where absorption of furanocoumarins occurs.

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