Grapefruit and statin drugs

[Fat Guy]

When you go on a statin drug for cholesterol you're told not to eat grapefruit. Then if you Google it you find hundreds of references saying it's fine to eat a grapefruit just don't go on a grapefruit-juice binge. So what's the deal? Can somebody give us an evidence-based primer on grapefruit and statins?

[haresfur]

NIH appears to recommend not drinking more than a quart of grapefruit juice a day Atorvastatin.

However, in the the Health and Human Services publication Medicine by Design they say some people can show an effect at lower levels:

Did you know that, in some people, a single glass

of grapefruit juice can alter levels of drugs used

to treat allergies, heart disease, and infections?

Fifteen years ago, pharmacologists discovered

this “grapefruit juice effect” by luck, after giving

volunteers grapefruit juice to mask the taste of a

medicine. Nearly a decade later, researchers figured

out that grapefruit juice affects

medicines by lowering levels of a

drug-metabolizing enzyme, called

CYP3A4, in the intestines.

More recently, Paul B. Watkins of

the University of North Carolina at

Chapel Hill discovered that other juices like Seville

(sour) orange juice—but not regular orange

juice—have the same effect on the body’s handling

of medicines.

My personal, non-medical practitioner thought, would be to avoid those juices completely when going on a drug with possible interaction and then introducing them slowly (in consultation with your doctor) only after you have established your response to the drug. But then, I didn't have a good experience with statins, anyway.

[ElsieD]

The only thing I have to add to this is to say that I am very interested in this topic. I used to love broiled grapefuit but have also been told not to eat it due to the statins I take. So, I haven'touched grapefruit at all since I started taking this drug. Yesterday I was at a large Asian supermarket and they had something called orange grapefruit. I had never seen one before and bought one. So now it's sitting on the counter looking at me and I'm wondering: Can it really hurt to eat this thing?.

[JasonW]

If you are taking CYP3A4 metabolized drugs, its pretty crucial you do not eat grapefruits because it can inhibit the enzymes responsible for metabolism possibly leading to build up of toxic compounds.

Some people have more CYP3A4 than other can therefore can drink more grapefruit juice before seeing any effects, but in the elderly or those with liver cirrhosis, these enzyme levels could be much more vulnerable to grapefruit.

Definitely consult your doctor before eating that orange grapefruit!

[Alex]

This is a great question, with some intriguing posts so far. Ever since starting Lipitor (atorvastatin) I've been extrememly careful about not eating even a little bit of grapefruit. I don't miss it terribly, but it would be nice to have that option if the occasion arose.

The official Lipitor web site has a link to a pamphlet that says grapefruit juice "Contains one or more components that inhibit CYP 3A4 and can increase plasma concentrations of atorvastatin, especially with excessive grapefruit juice consumption (>1.2 liters per day)."

However, it also says that consumption of 240 ml of grapefruit per day produced a 16% increase in the maximum plasma concentration of the drug and a 37% increase in bioavailability (unaltered drug in the bloodstream)

Regarding JasonW's comment, according to the Wikipedia entry for CYP3A4, "Variability in CYP3A4 function can be determined noninvasively by the erythromycin breath test (ERMBT). The ERMBT estimates in vivo CYP3A4 activity by measuring the radiolabelled carbon dioxide exhaled after an intravenous dose of (14C-N-methyl)-erythromycin." IV erythromycin doesn't sound "noninvasive" to me, but what do I know?

The NIH pamphlet that haresfur mentioned says, "Watkins and his coworkers have found that a chemical common to grapefruit and sour oranges, dihydroxybergamottin, is likely the molecular culprit." According to Wikipedia, regular old bergamottin also is found in grapefruit juice and shares responsibility for this enzyme effect. The entry adds, "To a lesser extent, bergamottin is also present in the essential oils of other citrus fruits." So now I'm wondering about Earl Grey tea. The amount of oil of bergamot probably is miniscule enough to not cause any untoward effects, but it still might be worth investigating.

[ensete]

when my husband's dr prescribed crestor for a low hdl/ldl ratio, we read up on it and decided to try the 8 week cholesterol curenew 8 week cholesterol cure instead. the oat bran, phytosterols and slow-release niacin program worked SO well, his dr assumed he was taking the crestor and had a very good response to it!

[gfweb]

Be careful w the niacin. Changed dose or even supplier of niacin can give hepatitis if the niacin is given in effective dosages.

If you want to do it naturally, fish oil is a safer thing. Two grams or so a day is the dose.

[JasonW]

haha IV ethryomycin is just a needle! Be brave!

[David Ross]

I've asked my Doctor in the past about the effects of grapefruit on one who takes Lipitor. He wasn't at all concerned, probably because I rarely drink much grapefruit juice and I usually only eat one grapefruit a week and that's only this time of year when it's in season.

[prasantrin]

Your best bet is to ask your doctor for a bibliography of studies regarding grapefruit and statins. I'm sure he would be a much better resource than a bunch of non-doctors on a food forum.

But should you choose to believe the internet is a better resource, take a look at this thread started by Gifted Gourmet. docsconz, who plays a doctor in real life, chimes in.

[Mjx]

I have to agree, this isn't something you'd want to take hearsay advice on. According to this article on the Mayo Clinc's website, there can be serious interactions between at least some statins and grapefruit juice. For a more in-depth discussion, 'Drug-grapefruit juice interactions' goes into the biochemistry and physiology. The bibliography given here may be useful, if the previous article isn't as relevant as you'd like, or you're interested in the way the research has developed in the last decade.

[cdh]

More gastronomically... anybody know anything about how grapefruit and natural statin-y compounds in stuff like oyster mushrooms play together?

[Fat Guy]

I've now read through just about every publicly-and-freely accessible article and paper on this issue, and I still don't feel all that much closer to an answer. But I do think that, especially at low doses of statin drugs, and talking about whole fruit rather than juice, it's hard for me to find a documented problem with having a grapefruit or two on any given day.

The two physicians I asked about this disagreed. One, an internist, took the hard line: stay away from grapefruit anything, in any amount, just in case. The other, a cardiologist, said you'd have to consume an abnormal amount of grapefruit products before being at risk. I'm not really sure either of them knows more about the subject than a literate person who has read the relevant material. In general, I don't buy into the notion that we should defer to doctors solely on account of their credentials. It's the content of what they say that matters.

I'm also wondering when furanocoumarin-free grapefruit juice is going to hit the market, if it hasn't already.