Toxins in Raw Mushrooms?

Toxins in Raw Mushrooms?
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Agaratine, a natural toxin found in mushrooms, is destroyed by cooking.

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Harmful, harmless, or helpful? Raw mushrooms. I got an email from someone last year saying that Dr. Joel Fuhrman told his patients to stop eating raw mushrooms, out of fear of a natural toxin in regular white mushrooms called agaritine, which is essentially destroyed by cooking.

Now, I get crazy emails all the time about doctors spouting all sorts of nonsense, but I have tremendous respect for Dr. Fuhrman, so I took it seriously enough to research the topic. And what do you think I found? Raw mushrooms: harmful, harmless, or helpful?

Has Furhman just drank one too many of his blended salads, or is he really onto something? He’s right. Mushrooms have all sorts of amazing health benefits, but eat them cooked.

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 tombothetominator via Flickr.

Harmful, harmless, or helpful? Raw mushrooms. I got an email from someone last year saying that Dr. Joel Fuhrman told his patients to stop eating raw mushrooms, out of fear of a natural toxin in regular white mushrooms called agaritine, which is essentially destroyed by cooking.

Now, I get crazy emails all the time about doctors spouting all sorts of nonsense, but I have tremendous respect for Dr. Fuhrman, so I took it seriously enough to research the topic. And what do you think I found? Raw mushrooms: harmful, harmless, or helpful?

Has Furhman just drank one too many of his blended salads, or is he really onto something? He’s right. Mushrooms have all sorts of amazing health benefits, but eat them cooked.

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 tombothetominator via Flickr.

Doctor's Note

What else do mushrooms do for us? Check out:
Breast Cancer Prevention: Which Mushroom Is Best?
Why Do Asian Women Have Less Breast Cancer?

And check out my other “HHH” videos – Harmful, Harmless, or Helpful? – listed below the post, as well as my other videos on mushrooms

For more context, see my associated blog posts:  The Most Anti-Inflammatory MushroomMushrooms for Breast Cancer PreventionErgothioneine: A New Vitamin? and Mushrooms and Immunity.

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

62 responses to “Toxins in Raw Mushrooms?

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    1. I eat raw white mushrooms all the time. Switching to cooked would be easy enough. Sometimes I microwave them for 30 seconds to make them soft and juicy. Is that sufficient to kill the toxins? What’s the best method, and minimum length of time to cook them to kill the toxins?




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      1. Hello Eric,

        Taking a look at the study, when microwaving, it appears that if you microwave for 30 seconds you lose 51% of the agaritine and after 45 seconds 60% of the agaritine is lost.

        To answer your question about the absolute best method to reduce agaritine, if you boil in water for 1 hour you lose 88% of the agaritine and if you freeze them for 30 days then allow them to thaw out on their own for 1 hour without microwaving you lose 77% of the agaritine. These are by far the best 2 methods it seems to reduce this toxin.
        https://mycotopia.net/forums/attachments/fungi-all-edible-medicinal-other-mushrooms/78237d1203797227-carcinogenesis-button-crimini-portabella-mushrooms-processingstoragedegradationagaritine.pdf

        You should note that there is also no “safe” level of agaritine as it is known as a human carcinogen, the tolerance should be 0. Of course, one could assume that reducing as much agaritine as possible would be not nearly as destructive as full exposure.
        http://books.google.com/books?id=vMDRLMP-FC4C&pg=PA26&lpg=PA26&dq=safe+level+of+agaritine&source=bl&ots=5b5tajAnBV&sig=mugP0fgo2HTM3_V1jNDiZDwHT-o&hl=en&ei=hIydTu75IOa1sQLv1KXgCQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBoQ6AEwAA#v=onepage&q&f=false

        For more on some typically consumed toxins, check out this video on Blue-green algae and Spirulina http://nutritionfacts.org/videos/blue-green-algae-spirulina/

        Hope this helped!




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          1. I see no problem in that as long as the sodium content is low. If its very salty, we might be able to reduce the sodium, at best, by 30%.




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          2. signmanbob: I have another thought for you concerning canned mushrooms – toxins leaching from the cans. I’m sure you’ve heard of the problems with BPA. But even if you can find a brand free of BPA, I have to wonder what else is in there that might be bad. What are they replacing the BPA with???? (That last part is just speculation on my part.)

            My tip on convenient mushrooms – get the pre-washed, pre-sliced mushrooms from the store. I know that Trader Joes and Market of Choice sell mushrooms this way. Then throw the mushrooms in the microwave (no oil or anything need be added) for a good 4-6 minutes. They come out perfect and you don’t have to deal with opening a can, draining, salt, BPA or anything else.

            Just a thought for you. Good luck.




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            1. Thank you Thea! That does sound good. I’ll have to see if I can find those around here.
              So if microwaving 4-6 minutes will get rid of the toxins in the mushrooms, that won’t be much trouble at all.




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              1. signmanbob: So glad the tip appeals to you.

                FYI: the reason I give such a large range of times is that cooking time depends on all these factors: your microwave power, how many mushrooms you are cooking, whether or not the mushrooms comes from the refrigerator or were sitting on your counter, and how thick/thin the store sliced them. (Trader Joes ones are thicker than Market of Choice. Depending on what I’m doing, both come in equally handy.)

                I just cook until it gets that cooked mushroom consistency. Once you get a brand you are familiar with, you will know exactly how long to cook them each time. It will be a snap.

                Another tip: The mushrooms naturally release their “water” into the cooking bowl. I scoop out the mushrooms, but leave the mushroom water. Then I add the chopped broccoli or cauliflower or whatever to the same bowl and cook it in the mushroom water. Yum! I usually do 3 minutes for broccoli. 4-5 minutes for cauliflower.

                Hope you can find those pre-sliced mushrooms I am talking about because it is so fast and comes out tasting so good. Good luck!




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      2. A good way to cook the mushrooms is by leaving them in the sun. This also helps them create more vitamin D. check this link www . therawadvantage.com/2013/02/ways-to-get-vitamin-d/




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  1. If agaritine is so toxic and cooking mushrooms does not remove all of it, wouldn’t it be healthiest to not eat mushrooms at all?  
    It seems the exposure to agaritine is more dangerous than any health promoting effects of mushrooms, right?




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    1. Although yes agaratine is toxic and yes agaratine is not completely eliminated, mushrooms are still higihly nutritious and the minute amounts we are exposed to when eating cooked mushrooms is not of a concern.




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          1. Vitamin C counteracts the carcinogen acrylamide produced by roasting coffee beans. I wonder if Vit C or another antioxidant would counteract agaritine?




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                1. Articles, blog posts, and news stories are not evidence, as this is what you will find when google searching. I need you to link an actual study so we can examine whether this claim you made is true or false.




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  2. http://www.mykoweb.com/articles/EatingRawMushrooms.html

    The kicker with Agaricus species, including the buttons, is
    that one of their primary hydrazine components, along with
    gyromitrin, is “agaritine,” a substance somewhat resistant
    to cooking heat, with a significant percentage (25–75%) of
    agaratine material typically remaining after being subjected to
    various methods of cooking. So, the question as far as avoiding
    hydrazines in Agaricus is concerned, actually becomes whether
    to eat members of this genus at all.

    We need to keep in mind that lab tests and subsequent
    conclusions drawn concerning carcinogenic or mutagenic
    health hazards of hydrazine involve massive doses of isolated
    extracts administered to mice in a concentrated time frame.
    Similarly disturbing test results are likely to be found with many
    substances present in many, many foods humans commonly
    eat without suffering or even worrying about any particular
    health concern. The relatively unblemished human history of
    consuming edible Agaricus species suggests we may continue to
    do so.




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    1. So have many people, and I have never heard of anyone getting sick from raw mushrooms. It’s common sense, if you ask me. I eat raw mushrooms in abundance and am extremely healthy. I literally haven’t gotten sick once since going WFPB vegan. I don’t even get headaches.




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  3. Worth noting that the initial toxicological studies fingering agaritine in mice (but not rats) used rather extreme protocols.

    “Feeding studies using mushrooms and mushroom extracts have in general provided no evidence of toxicological effects of agaritine or mushroom consumption, in contrast to results of studies which have administered non-physiologically relevant concentrations of chemically synthesized hydrazine derivatives to mice. The available evidence to date suggests that agaritine from consumption of cultivated A. bisporus mushrooms poses no known toxicological risk to healthy humans.”

    Roupas, Peter, et al. “Mushrooms and agaritine: A mini-review.” Journal of Functional Foods 2.2 (2010): 91-98. http://www.sciencedirect.com/science/article/pii/S1756464610000241




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    1. I think we can conclude that we have to take Dr Greger advice with a pinch of salt :). He also seems to be demonizing coconuts but very pro soy. Go figure!




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  4. Hello. I love you Dr. Greger!

    Yesterday I ate several raw white button mushrooms (even after viewing your mushroom video) so I was a little concerned. I went to “sources cited”, and saw evidence of the agaritine content, but I wanted to know why agaritine from mushrooms was considered so toxic.

    I found this 2010 “mini review” from Australia that concluded there was no evidence of toxic effects from eating raw mushrooms:

    Roupasa P, Keoghb J, Noakesb M, Margettsa C, Taylorb P. Mushrooms and agaritine: A mini-review. Journal of functional foods. 2010;2(2):91-98.
    According to the conclusion:

    “Direct administration of chemically synthesized hydrazine compounds, including agaritine, to mice has been reported to be associated with potential carcinogenic effects in some studies, but contradicted by other studies. No carcinogenic effects have been scientifically validated in studies with mice, rats or humans where mushrooms have been consumed…A critical analysis of the studies to date leads to the conclusion that consumption of A. bisporus and other edible
    mushrooms does not result in any known toxicological or carcinogenic
    effects in healthy humans.”

    Please note that the review was funded by Mushroom and Health Global
    Initiative (MHGI).

    Do you happen to know if there are any studies on consumption of edible mushrooms that have found toxic effects?
    Thanks for being a fantastic resource!




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  5. The source cited seems to be about the agaritine content not about its level of harm. Also, agaritine doesn’t seem to be all bad, e.g. the article “Agaritine purified from Agaricus blazei Murrill exerts anti-tumor activity against leukemic cells.” http://www.ncbi.nlm.nih.gov/pubmed/20347942

    Which states “The results indicate that agaritine from ABM has direct anti-tumor activity against leukemic tumor cells in vitro. This is in contrast to the carcinogenic activity previously ascribed to this compound.”
    Is there conclusive evidence that agaritine is harmful if consumed in raw mushrooms? I couldn’t find it.
    Thanks.




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  6. Is there a difference between “Fresh Cooked” and Canned Mushrooms? In other words is the efficacy of the mushroom diminished by the canning process? Or are canned and cooked on par?




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  7. This review found that there is no evidence that consumption of agaritine in mushrooms leads to any toxicological effects.
    http://www.sciencedirect.com/science/article/pii/S1756464610000241

    Most of the animal studies that found toxic effects resulting from agaritine used an isolated form in very high doses that are not representative of whole mushroom consumption. Given that agaritine is a known toxin, it’s a decent precaution to cook mushrooms. But given the lack of evidence of any real toxic effect from human consumption of whole raw mushroom, I’m not going to lose any sleep over it.




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    1. Well I put raw mushrooms in my smoothies all the time… in high amounts sometimes. I’ll eat a cup of raw mushrooms or more sometimes. I literally never get sick, never get head aches, and so on… I haven’t experienced any ill effects. I adore Dr. Greger but I do find it horribly annoying to red light such a healthy food with such little explanation. I’d say that’s his only flaw. For example, due to a petri dish occurrence when human cells were drenched with avocado, he red lighted this healthy fruit even while admitting the petri dish incident wasn’t necessarily telling about what happens when this fruit is ingested in real humans.
      And he green lighted MSG and while yes, naturally occurring MSG is totally fine, it is COMPLETELY different than the MSG added to enhance flavor in certain foods (mostly junk foods).
      And for that matter, in regards to toxins being present in certain foods… well, there are toxins present in some of the healthiest plant foods in existence. Cyanide is in flax for example. In plants, it seems that any toxins are not absorbed by the body due to fiber and antioxidants and likely their high mineral content as well (as I’ve read that when you have enough minerals, your body is less likely to absorb heavy metals). So why freak out about a relatively newly discovered toxin in another plant when no one is freaking out about naturally occurring toxins in other healthy plants?
      And for the record, anyone concerned about cyanide in fax, I consume 2 tbsp of ground flax a day as a rule, though sometimes more, last summer I would sometimes have a LOT more than that (like a half a cup). I got my blood checked for a lot of things due to a past experience and cyanide was on the list, my results came back perfect.




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    2. Hi, thanks for posng. I was about to comment on the descrepancy between argentine in an undigested mushroom and argentine in a digested mushroom. When subjected to the environment of the human stomach, would the toxin remain?

      There’s also the dosage, as you were saying. Normal dosage in a diet is different exposure to isolating and concentrating the toxin. It’s also possible that there is something in the whole mushroom that counteracts or neutralizes the toxin.

      Studying the effects of a concentrated, isolated toxin is not sufficient to conclude that a low amount of the toxin in a whole food is toxic. More evidence, such as long term studies on mushroom eaters would have to be done to convince me.

      Nevertheless, I will be cooking my mushrooms until I am convinced.




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      1. Why bother cooking? There are countless whole plant foods that contain substances which are harmful at very high doses. In fact, pretty much every substance is harmful at a high dose, even water. For example, solanine is present in small amounts in a wide variety of plant foods that are commonly consumed.

        It makes no sense to make this special consideration for raw mushrooms when there is no evidence that they are actually harmful. Dr. Greger and Dr. Fuhrman’s fear mongering over uncooked mushrooms demonstrates inconsistent reasoning on their part.




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  8. Garcinia kola or bitter kola nut—not to be confused with the regular kola or cola
    nut–is traditionally used by African medicinemen who believe that it
    has purgative, antiparasitic, and antimicrobial properties. The seeds
    are used for bronchitis, throat infections, colic, head or chest
    colds, and cough. It is also used for liver disorders and as a chewing stick. Reports
    say it cures viruses—Even Ebola. What does Dr. Greger say about it?




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  9. I’m reading How Not to Die (amazing book, I want to buy it for everyone I know) and have a question about mushrooms. As an avid mushroom hunter, I am wondering why you would say “all wild-foraged mushrooms should be on the red light list” – are you punishing chanterelles for the sins of the morel?




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    1. Danilo: Until the mushroom has the texture of a cooked mushroom as opposed to a raw mushroom.
      .
      I’ve got this down to a science for my needs. I like to buy the pre-sliced button mushrooms. It takes 5.5 minutes in the microwave for one 8 to 10 ounce package. If I’m cooking two packages, it takes 8.5 minutes. These times are for mushrooms that have been in refrigerator.
      .
      I find that mushrooms are pretty forgiving, so over cooking a bit might make them a bit tougher, but they still work great and sometimes tougher is exactly what you want for an application.
      .
      Good luck.




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      1. doesn’t microwaving kill enzymes in food? would it not be the same with the beneficial nutrient properties of the mushroom – especially if you don’t use the low power setting?




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        1. Danuta: Microwaving does not kill enzymes any more than regular cooking does. And your original question was about how long to cook mushrooms.
          .
          As for “killing enzymes”, that’s not something I usually worry about. (The following video talks about an enzyme that matters, but note the video description “There are a few examples of plant enzymes having physiologically relevant impacts on the human diet…” http://nutritionfacts.org/video/sometimes-the-enzyme-myth-is-true/ ) Plenty of studies show a great deal of healthy outcomes from eating cooked food. So, I eat some cooked food and some raw food. That seems to be a good approach in general. Though when it comes to mushrooms, as explained in the above video, the general advice would be to eat only on cooked mushrooms.
          .
          There are a lot of myths about microwaves out there. Here is a great article for dispelling those myths: http://www.drmyattswellnessclub.com/Microwave.htm So, this is good news! Enjoy your microwave!! :-)




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  10. Is it true that people with kidney disease can’t eat mushrooms because of the phosphorus in it? Ailing kidneys can’t filter it out of the blood hence raising the person’s potassium level causing heart issues and blood pressure issues.




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  11. Perhaps just as nutrients are better sourced in whole foods, the negative effects of toxins are rendered more harmless in whole foods. Does reductionism apply to both? I would like to see studies that show the negative health effects of eating mushrooms rather than agaraitine, (although I do not support poisoning mice for research). Perhaps it is impossible to feed mice enough mushrooms cause problems.




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  12. Gosh, I have been eating a very delicious marinated mushroom dish for many years! A bit concerned, now, or does marinating them in lemon juice/vinegar sort of cook them?




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  13. The only ones that may be toxic are the wild ones found on watershed and pastures.Ask Paul Staments at Fungi Perfect. In Olympia Washington. He is the for most authority on Mushrooms of all kinds. Check out his site. He offers classes and kits. Have fun. He does.




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    1. Ahh ok, then that might explain why despite eating raw mushrooms regularly, I’ve never experienced any ill effects and am in excellent health. Though here he talks about white button mushrooms. But people have been eating these raw since forever and they’ve been fine and probably only benefited. I hate the “red light” on such healthy foods with such little explanation. HATE it.




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  14. I totally disagree. We’ve been eating raw mushrooms for so many years. I put raw mushrooms by the cupful, sometimes, in my smoothies and I have never had anything but positive results. I read about this and have never experienced any symptoms. I would be interested in seeing a study observing people consuming raw mushrooms. Until there is more explanation, I will not be afraid of eating this food raw. Also, mushrooms are so healthy, by being afraid to put them in salads or even smoothes for fellow hard core smoothie makers like myself, it could decrease the amount we eat. Because they also have so many protective compounds, perhaps that’s the reason this relatively newly discovered toxin has never seemed to effect anyone, at least not that I’ve heard of or witnessed.




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    1. But then, I also disagree about regular potatoes being harmful. It seems unnecessarily cautious. If I were in the wild, I’d go by what people seemed to do well on and what I seemed to do well on, I sometimes think these studies can be over concerned and that this amount of worrying is more damaging than anything else.




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    2. I agree, but the only things I disagree are the arguments that because we’ve been eating something for so many years, therefore, it makes it safe, and the argument that if one person can eat something for years and still be alive and healthy, therefore it is a nutritious food. Not every meat eater gets cancer and dies young. Not every food we’ve been eating for years turns out to be beneficial for us, after all. Agreed on the needing a study following people with mushrooms. I suspect and hope that your hypothesis about raw mushrooms is true!




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  15. What heat do I need for the mushrooms to remove the agaratines & make them safe to eat? I’d like to keep them as raw as possible.




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    1. I think some comments above said microwaving them on high for at least a minute, and other comments said boiling them for a couple hours. Mushrooms are a food you probably don’t want raw. Some foods are toxic when consumed raw, while others are very nutritious consumed in their raw or whole forms, so the raw food diet can’t be universally applied to every food. Mushrooms might need to be added to this list.

      https://www.aol.com/food/9-foods-you-should-never-eat-raw/#




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  16. More facts…
    Don’t worry about it!
    Benefits out weigh the risks.
    The amount one would have to eat over a lifetime, to even be a 1 in a 100K risk is absurd.
    Cancer showed in a test tube… Not in human subjects!
    Don’t forget, the sun is a carcinogenic too!
    If you are a worrier…. cook em…. Reducing that stress will have more affect than cooking….
    but why worry??

    A more in depth video on the subject…
    https://www.scientificamerican.com/article/raw-mushrooms-hazardous-or-harmless/




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    1. She also plays down the risks of eating red meat, saying that meat eaters don’t have to give up foods they love in order to be healthy and cancer-free

      http://www.quickanddirtytips.com/health-fitness/prevention/eating-red-meat-causes-cancer-not-exactly

      She seems to have less vigilant approach to nutrition as Dr. Greger, so I’m not sure if you can really use her ideas to refute his. She also says is an article about grass fed vs. grain fed that she still hasn’t figured out where she lies on the vegetarian spectrum. That makes me trust her a little less than Greger. She might be in a habit of playing down the risks of foods she likes or has considered in the past to be healthy.




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