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How Much Broccoli Is Too Much?

Four cups of broccoli sprouts a day may exceed the safe dose of the cruciferous phytonutrient sulforaphane.

March 16, 2012 |
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Supplementary Info

Sources Cited


Image thanks to adactio.


It’s nice to know there were no apparent adverse effects even at 27 cups of broccoli a day’s worth of these cruciferous phytonutrients, but has to be some point at which it becomes toxic, and indeed there is. Some researchers in Italy tried to push the envelope,. They’re trying to come up with an infusion dose to use as actual chemotherapy and so wanted to know how high they could go. And yes, there is a level at which you can cause DNA damage at the equivalent of about 100 cups of broccoli a day or actually just 4 cups of broccoli sprouts. They conclude no sign of DNA lesions could be observed at nutritionally attainable concentrations. But that’s not really true. I mean you could eat four cups of sprouts a day. See they don’t know health nuts like I know some health nuts.
Someone came up to me after a lecture a few years ago and said how he heard that wheatgrass juice was good for you, cleans you out, and so he wanted to try stuffing himself with it. So he told me he calculated the volume of the human digestive tract—all ten yards or so—and proceeded to drink that amount continuousy—quart after quart—until, it started coming out the other end. So I asked him, well, what happened ? And he looked up at me, with an expression that I can only describe as rapture, and said—no joke, It was volcanic.

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring watch the above video. This is just an approximation of the audio contributed by veganmontreal.

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Dr. Michael Greger

Doctor's Note

This video is a follow-up on yesterday’s video Liver Toxicity Due to Broccoli Juice? and is video #7 of my 13-part series on the latest science on cruciferous vegetables. See Kale & Immune SystemSmoking vs. KaleDNA & BroccoliBroccoli vs. Breast CancerSulforaphane and hundreds of my other videos on more than a thousand subjects.

For some context, please check out my associated blog posts: The Best DetoxBroccoli Boosts Liver Detox Enzymes, and Nutmeg Toxicity

  • Michael Greger M.D.

    This video is a follow-up on yesterday’s video Liver Toxicity Due to Broccoli Juice? and is video #7 of my 13-part series on the latest science on cruciferous vegetables. See Kale & Immune System, Smoking vs. Kale, DNA & Broccoli, Broccoli vs. Breast Cancer, Sulforaphane and hundreds of my other videos on more than a thousand subjects.

  • Poxacuatl

    Lol! Volcanic. NOT a good visual to start my morning, Doc ;^)

    But, seriously, wasn’t he putting his life in danger? I recently recall a person died consuming water like that — continuously. Some self-experimentation is just insane.

  • Marc Slavin

    Some people like to climb mountains and others like to push the envelope overdoing wheat grass! I guess that it takes all kinds! :)

    • John Galt

      “Dr.” Ann Wigmore advocated wheatgrass “implants”. Since broccoli sprouts are nutritionally superior to wheatgrass and it deters prostate cancer (according to John Hopkins doctors; look for the smiley face in the produce dept.) and since it would be very close to the prostate, what about “broccoli sprout implants” for prostate cancer self-treatment???

  • newvegan

    My daughter told me that Turnips are a super food. Very low in calories and contain almost all vitamins. Is the turnip all that?

  • GeorgeI

    Dr. Greger, I laughed so hard at your line “they don’t know health nuts the way I know some health nuts”.

    I’ve met so MANY of those people over my life and your delivery was great.

  • sodium

    Is one cup of broccoli sprouts about 70-80grams?

    • Michael Greger M.D.

      No, I think 70-80 grams would be more like 2 and a half cups.

  • Bret Iron

    So, is 4 cups of Broccoli sprouts not good??