How Much Broccoli is Too Much?

How Much Broccoli is Too Much?
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Four cups of broccoli sprouts a day may exceed the safe dose of the cruciferous phytonutrient sulforaphane.

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It’s nice to know there were no apparent adverse effects at even 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 IV infusion dose to use as actual chemotherapy, and so wanted to know how high they could go.

And yes, there was a level at which you can cause DNA damage—at the equivalent of about 100 cups of broccoli a day—or actually just four 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 the 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 down in Florida, and said how he heard that wheatgrass juice was so 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 continuously—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—no joke—said: “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.

Please consider volunteering to help out on the site.

Image thanks to adactio / flickr

It’s nice to know there were no apparent adverse effects at even 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 IV infusion dose to use as actual chemotherapy, and so wanted to know how high they could go.

And yes, there was a level at which you can cause DNA damage—at the equivalent of about 100 cups of broccoli a day—or actually just four 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 the 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 down in Florida, and said how he heard that wheatgrass juice was so 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 continuously—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—no joke—said: “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.

Please consider volunteering to help out on the site.

Image thanks to adactio / flickr

Doctor's Note

This video is a follow-up on yesterday’s video Liver Toxicity Due to Broccoli Juice? and is video number seven of my 13-part series on the latest science on cruciferous vegetables. See Kale and the Immune SystemSmoking vs. Kale JuiceDNA Protection from BroccoliBroccoli Versus Breast Cancer Stem Cells; and Sulforaphane: From Broccoli to Breast.

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

If you haven’t yet, you can subscribe to my videos for free by clicking here.

 

34 responses to “How Much Broccoli is Too Much?

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  1. 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.

    1. “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???

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

  3. 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.

      1. Hello Dr Greger

        How much sulphoraphane does that represent?
        Dr Rhonda Patrick advises 100/140g per day to get 40/60mg of sulphoraphane which is the amount of sulforaphane that was used in studies to bring all the health benefits observed.
        Are her calculations wrong when converting sprout weight to sulphoraphane weight?
        Nowhere on the net is this conversion rate available and I’d say its the key information when trying to control our sulforaphane intake.

        Thanks!

        1. Hi, Denis. As I mentioned in a previous reply, the amount of sulforaphane in broccoli or broccoli sprouts can differ across varieties and with alterations in growing conditions. For that reason, it is not possible to give a conversion that will be accurate for all plants. If you want to follow Dr. Patrick’s advice, then use the amounts that she suggests. I think the idea here is to consume reasonable amounts of broccoli or sprouts, and not to try to push the envelope toward the level at which toxicity could occur. I think 100-140g of broccoli sprouts is a lot, and could potentially be too much. I certainly would not exceed 100g myself. I hope that helps!

  4. Dr. Gregor, I find use of cups as a form of measurement too confusing to translate into scientific terms. Could you please translate 4 cups or 1.25 cups into ounces or grams? Thanks

  5. Dr. Greger, I find the use of cups as a unit of measurement confusing and unsciencific. Could you rephase your references using grams or ounces please? Thank you! (So how many ounces or grams is 4 cups or 1.25 for that matter?)

  6. I’ve taken to eating raw broccoli, which has much more sulforaphane. So this upper limit would decrease to what value?

  7. Based upon a chart in the video here https://www.youtube.com/watch?v=zz4YVJ4aRfg., showing the glucosinolate precursor levels of the various cruciferous vegetables I calculate the upper limit Dr. Gregor is talking about here as 1285 mg glucosinolate precursor.

    In a comment above he gives 70-80 g as equalling 2.5 cups of sprouts. This means 4 cups of sprouts equals 128 g (80 g ÷ 2.5 cups = 32 g per cup), and based on the table in the video cited above this equates to 1285 mg of glucosinolate precursor a day (128 g ÷ 28 g = 4.57 x 281 mg glucosinolates = 1285 mg). I personally eat raw Brussels sprouts, and this equates to 6 cups or 543 g of them (1285 ÷ 104 mg glucosinolates = 12 x 1/2 cup or 44 g). This is a little over a pound which is the size they usually come in, so don’t eat more than a whole bag a day!

  8. I agree with most comments saying this leaves an uncomfortable question mark on how much actual sulphoraphane is too much.
    Rhonda Patrik talks about taking 100g-140g of broccoli sprouts per day, which according to her equates to 40-60mg of sulphoraphane. This is the dose used in many experiments on the effects of sulphoraphane and leads to all the improvements talked about when talking about sulphoraphane.
    Are her calculations off?

    Thank you in advance

      1. Hi! Thank you for your answer
        Would you please share with is how to calculate sulforaphane content in broccoli sprouts? This calculation seams to differ wildly with that pf Dr. Patrick and I’d like to understand the unlying reasonings

        Thank you again!

        1. Hi, Denis. As shown in this article, the amount of sulforaphane or, for that matter, just about any compound in a plant, will differ depending on the variety and growing conditions. For that reason, it is impossible to provide a conversion calculation that will be accurate for every broccoli plant or batch of sprouts. We can get a ballpark estimate from research that has been done, but Dr. Patrick may be quoting different research, and the plants or sprouts used in another study may have yielded different amounts of sulforaphane. I think the idea is to eat reasonable amounts, and not to try to reach the level at which toxicity occurs. In other words, if some is good, more is not necessarily better. I hope that helps!

  9. So I’ve purchased Broccoli sprouts to replace the broccoli I eat each day. Does anyone know how much broccoli sprouts I need to consume to achieve the nutritional equivalent of a cup of raw chopped broccoli?

    I remember watching one of Dr. Gregers videos…something about 2 Tablespoons of broccoli sprouts per day is sufficient, but i can’t honestly remember.

  10. I’ve purchased Broccoli sprouts to replace eating broccoli every day. Does anyone know the nutritional equivalence of Broccoli sprouts to 1 cup of chopped Broccoli?

  11. Hi,I am so grateful to you all. I have switched to a whole plant based diet and believe it has saved my life.
    My question is related to getting too much broccoli.
    While trying to save time cooking: suppose that I bought broccoli in season, washed a huge bunch with salt water and then put it all through the blender in one big batch. Then waited for an hour, cooked it and froze it in little glass containers to pull out of the freezer on my rush to work and use year round.
    Is it possible that having it wait that long (wait in frozen form for months…) would cause too much sulforaphane to be born? Could the same toxic effect of eating too much broccoli stumps be caused by having it wait in pureed or blended form for too long a time?
    God bless you all

    1. Hi I’m a health support volunteer. That is a very interesting question that I just don’t think has been studied. I don’t think we know how much sulforaphane would be produced in the situation you described because it hasn’t been tested. My suspicion is no, you are not going to have too much sulforaphane but I don’t think we have actual data on this. Here is some more information Dr. Greger has done on frozen broccoli and cooking broccoli which may give you some more time saving ideas with your vegetables.
      https://nutritionfacts.org/video/second-strategy-to-cooking-broccoli/
      https://nutritionfacts.org/2016/02/09/how-to-cook-broccoli/
      https://nutritionfacts.org/2012/04/12/the-best-detox/

      NurseKelly

  12. In other words is there a reason why Dr. Greger chops broccoli every morning and DOESN’T chop a big batch for a week’s use in one chop to save time?

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