Doctor's Note

Another benefit of not taking drugs? You don’t have to worry about grapefruit consumption! See Say No to Drugs by Saying Yes to More Plants.

We don’t want to take cholesterol-lowering drugs unless we need to. See Statin Muscle Toxicity. To get cholesterol down naturally, see:

Another video on the risks associated with taking estrogens: Plant-Based Bioidentical Hormones

Other videos on citrus include:

Can’t eat grapefruit without sprinkling sugar on top? Try erythritol instead just to avoid the empty calories: Erythritol May Be a Sweet Antioxidant.

For more context, check out my associated blog post: How Grapefruit Affects Prescription Drugs.

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  • A Mother And Her Calves

    Please check out the petition below (link included) petitioning Whole Foods

    Market to provide to the consumer a different line of dairy products.

    While the likelihood of Whole Foods doing this is slim, the awareness it will raise will possibly create a lot of people getting off dairy. The average consumer has absolutely no idea that 99 percent of US dairy comes from mother cows separated from their calves, denied what they gave birth to. Please let me know what you think of the petition, and please pass it on if this resonates with you.

  • Southlander

    I tend to try to always err on the side of caution. I can and will do without the grapefruit.

    • Roy Strachan

      Better to do without Lipitor!

  • Adrien

    Interesting, I suppose we could use grapefruit to have a better buzz from tea instead of coffee. Correct me if I’m wrong, but it seems that is the opposite effect of broccoli ! Is that overall great ? Could it decrease the benefice of broccoli ?

    • Darryl

      Bergamottin from grapefruit juice is one of many direct inhibitors of the CYP3A4 enzyme. Sulforaphane is not metabolized by CYP3A4, so there doesn’t appear to be any inhibition in that direction. In vitro, extraordinarily high sulforaphane levels can reduce transcription of the CYP3A4 gene. The tested 10μM concentration is much higher than that seen from broccoli ingestion (< 0.1 μM peaks from 200g broccoli is typical), and even that just resulted in 30% reduction of CYP3A4 transcripts. Very high doses of broccoli sprouts might have a minor and additive effect upstream of grapefruit on CYP3A4 drug metabolism.

      • Adrien

        Thanks Darryl.

  • Steve

    Does this mean mixing grapefruit with alcohol will get me more drunk?

  • Pres

    The dear doctor has it mostly just backwards. Grapefruit will enhance the adsorption of many foods. For example, if you need to eat a cup of broccoli you can get about the same effect by eating 1/2 cup along with grapefruit. Also, most oral medicines can be significantly reduced (25-75%) by taking some grapefruit with them. Saves money and you a quicker effect from the consumption.

    • Toxins

      What evidence do you have supporting this statement?

    • Thea

      Pres: I thought Dr. Greger did an excellent job of explaining *how* grapefruit can be of both benefit and of harm (ex: when combined with certain drugs). And he has the studies to back up his statements. Just what is it that you think Dr. Greger got wrong?

  • Plantstrongdoc M.D,

    I guess the point is to eat grapefruit, other fruit, vegetables, beans and grains (98% of the time) in the first place, in an attempt to avoid prescription drugs.

  • Ra

    Lately the videos are coming through but not the voice part. I get other videos so I am not sure it is me. Has anyone complained about that. thanks.

    • Coacervate

      No problems here Ra.

    • Thea

      Ra: I am having the same problem. The solution is to click the Volume symbol that is right next to the play symbol.

      For some reason, YouTube is setting the volume to “mute” by default for several of us. I have no idea why. I first noticed this problem for myself yesterday and it persists through today. At least there is an easy work around.

      Hope that helps.

  • Gui Leal
  • Thanks for this! Just eat a healthy, plant-based diet, and we should be fine….

  • Enola Knezevic

    Does grapefruit also lower the effectiveness of oral contraceptives like St. John’s wort does?

  • RM

    Not trying to be a stickler about it, but at 3:09 in the video it should be “blood concentrations *to* 137%”, not *by* 137%. I was listening to the audio and this had me do a double take.

  • fineartmarcella

    I’m a student NP, I would like to keep the last chart entitled ‘Grapefruit-Drug interactions and alternative therapies’ handy, but I cannot see the reference, could you please direct me to the origination of this chart?

  • Broccoli Lover

    So . . . does grapefruit consumption enhance the bioavailability or blood levels of natural nutrients such as alma, broccoli sprouts, etc.?

  • You always seem to have the latest info. I just read about the drug interaction on another site. This got me wondering if a plant based diet could actually reduce/eliminate the dependency upon the type of drugs that cause the interaction. Thanks.

    • Roy Strachan

      I was only on beta blockers, but now I’m on a plant based diet and have normal blood pressure without the beta blockers.
      I take no drugs prescription or otherwise and feel great.

  • Lawrence

    Dear Doctor, Have you seen any studies on recombinant apoA-Im and are you aware of any plant based food sources? Thanks.

  • intrigued

    I have been able to find studies of Chloroform extract of Papaya Seed being used as a MALE CONTRACEPTIVE conducted on animals but was intrigued to know if there were any further studies that have been conducted on actual humans. A male contraceptive with no adverse side effects derived from a Whole food, what a concept!!

  • Darryl

    Suggested related topic for a future video: Tell Your Doctor if You take St. John’s Wort

    The active compound in the herb St. John’s Wort, hyperforin, is a potent inducer of the pregnane X receptor and subsequent cytochrome and drug transporter expression, and hence dramatically speeds metabolism and reduces tissue levels of many drugs. Undisclosed St. John’s Wort self-medication has resulted in transplant rejection and unwanted pregnancy with oral contraceptives, and is common enough that a video covering the topic would be a public health service.

    • Joseph Gonzales R.D.

      NOTED! Thanks, Darryl.

  • dorange

    I would appreciate your comments (or maybe a new video…) on this chapter, Dr. Greger: Fruit/Vegetable-Drug Interactions: Effects on Drug Metabolizing Enzymes and Drug Transporters []

    • Joseph Gonzales R.D.

      Hi Dorange. Thanks for your note. Anything specific you’d like to know about the paper?

      • dorange

        Hi, thanks for the reply!
        Well, I found it very confusing… it seems anything we eat has a potential bad effect, particularly if a person is taking any drugs. I have particular interest in how to make the enzyme Cyp3a4 work in our benefit (through diet), helping in estrogen detox. It seems that eating grapefruit, grapes and even leafy vegetables, for example, deplete the enzyme, increasing circulating estrogen!? Cranberry juice seems to have the opposite effect, though. Could you clarify this, please. I believe this is very important for people with estrogen dominance, and estrogen induced cancers. I wonder how these would also relate to young females taking contraceptives.

        • Joseph Gonzales R.D.

          Plant’s do not contain estrogen. Only in isolated and concentrated forms could be they be problematic. Doctor’s are pretty good about discussing potential drug-nutrient interactions. Grapefruit is perhaps the most common. Also, too much vitamin K from dark leafy greens can effect warfarin, but to my knowledge doses can be adjusted so folks can still eat greens. Other Doctor’s may be able to help me answer this question in more depth. I really like your link, thanks for sharing! Especially table 1 describing traditional uses for plants. I think you’re onto something, as “food is medicine” and it will have thousands of biochemical reactions in the body. Still, plant-based diets seem to offer the best protection for health and wellness.

          • dorange

            Thanks! I am onto plant based diets! :) Now, my question would be which foods, besides cranberry juice (which has too much sugar…), would help enhance Cyp3a4 enzyme and estrogen detox?