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Eating Green to Prevent Cancer

Chlorophyll, the most ubiquitous plant pigment in the world, may protect our DNA against mutation by intercepting carcinogens.

October 16, 2012 |
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Supplementary Info

Sources Cited


Images thanks to: Gigillo83 and Jynto via Wikimedia Commons.


Why do people who eat more plants get less cancer? We've talked about some phytonutrients that can act as antioxidants to douse free radicals, how some can boost our liver's own detoxification enzymes, and some that even boost our DNA repair enzymes to patch-up any damage done. But twenty two years ago the interceptor molecule hypothesis was postulated. Serving as a first line of defense interceptors bind to mutagens and carcinogens and thereby block them from coming in contact with our DNA.

Many carcinogens, shown here in blue, have a flat ring system narrow enough to slip into the spine of our DNA causing mutations, but if the interceptors glom onto the carcinogen first, it may no longer fit. So the search was on, combing for the existence of carcinogen-binding molecules, and in 2007 we discovered one such amazing molecule was … chlorophyll! The most ubiquitous plant pigment in the world, that which makes dark green leafy vegetables dark green.

In subsequent years, the ability of chlorophyll to “totally abolish” DNA damage of human cells exposed to carcinogens was documented in a petri dish, but what we really need is to see if it works in people, but you can’t just give people carcinogens—unless, you pay them enough. “Effects of Chlorophyll on Low-Dose Aflatoxin in Human Volunteers.”

They had people drink a solution of radioactive aflatoxin, the carcinogen that used to be a problem in peanut butter, with or without spinach chlorophyll . Here’s the big spike in their blood stream of aflatoxin without spinach in their stomach, and this is with. Apparently the chlorophyll bound to the aflatoxin and preventing its absorption into their systems. “In sum, these studies provide substantial evidence that chlorophylls can strongly inhibit uptake of aflatoxins in the whole animal,” which in this case, was us.

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 Kerry Skinner.

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Dr. Michael Greger

Doctor's Note

For more on the antioxidant mechanism, see Antioxidant Power of Plant Foods Versus Animal Foods. For boosting our liver's ability to detoxify carcinogens, see The Best Detox, and for boosting our DNA repair enzymes,Kiwifruit and DNA Repair. These are but a few of the various beneficial roles played by Phytochemicals: The Nutrition Facts Missing From the Label, and it's not just the green pigments. There are the yellow onesorange onesred ones, and blue ones. Sounds like a Dr. Seuss book! That's it for volume 10—thanks for everyone's continued interest in my work. Volume 11 starts tomorrow!

For some context, please check out my associated blog posts: Eating Green to Prevent CancerPrevent Breast Cancer by Any Greens Necessary, and Foods That May Block Cancer Formation

  • Michael Greger M.D.

    For more on the antioxidant mechanism, see Antioxidant Power of Plant Foods Versus Animal Foods. For boosting our liver’s ability to detoxify carcinogens, see The Best Detox, and for boosting our DNA repair enzymes, Kiwifruit and DNA Repair. These are but a few of the various beneficial roles played by Phytochemicals: The Nutrition Facts Missing From the Label, and it’s not just the green pigments. There are the yellow ones, orange ones, red ones, and blue ones. Sounds like a Dr. Seuss book! That’s it for volume 10—thanks for everyone’s continued interest in my work.

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

    • Jo

      Can’t wait! Have been looking forward to “Saffron for PMS.” Already purchased squash seeds, based on one of your videos, for the same reason.

    • HemoDynamic, M.D.

      I’m Green with Envy!

    • Strix

       I don’t know, Dr. G.

      .To the villagers of Whoville he’ll serve up red meat
      You recall the holiday table offering “roast beast”
      And surely the green eggs paired with fat ham
      would not be the green we want to feed to our fam.

      The heart of the Grinch was enlarged with compassion,
      or so says Dr. Seuss
      but perhaps it was that serving of browned butter moose.

      Dr. Seuss may be colorful be he needs to “green up.” Love the Lorax, but he’s got to do better ;^) Maybe a New Seuss book is in order.

  • Maria

    This is great! 
    However, is this saying that we have to consume the chlorophyll and carcinogens, simultaneously?  Or is it not enough to have the chlorophyll in our bodies so that when we do eat carcinogens it is there to protect us??

    • Strix

       Good question! Absorption is always a concern. There are so many “what-if’s” that my philosophy is to just load up on the greens and assume the best. But, yea, I would like to know all the details. We are all so different, that no matter what studies or facts show, there are always variables that can change it for certain people.
      all I know is, Greens have been the #1 healing food for me.

      GO Greeeeeeeeeeeeeeeeens!!!!

      • Valnaples

        Strix, I have a pot of flat leaf parsley always growing out front and I try to grab a bunch of it *every day* to eat…sometimes even on my way to work…LIVE greens with their beautiful chlorophyll are even nicer! But folks, DO what you can to heed Doc’s advice…great video here! *EAT*GREEN*EVERY*DAY!

        • Strix

           Awesome! Instead of grabbing a doughnut, right? I bet you have the best morning breath in your town.
          My favorite living food is broccoli sprouts. Those are a staple for me.
          I like parsley. It’s a little underrated, don’t you think? I used to juice it all the time, but find I like a big handful in my salads too.

  • BPCveg

    Thanks Dr. Greger for this excellent video. I appreciate that we come away learning something new about why plant-based diets work.

    Interestingly, this study looks at preventing the initiatiation step of cancer by chlorophyll binding to aflatoxin – the same carcinogen that Dr. Campbell (from ‘The China study’) discussed in connection with studies on cancer promotion.

  • Boblehnberg

    In the aflatoxin-chlorophyll study, did they consider intake of animal protein (or was it plant based diet only)? The China Study reported increased animal protein intake increases carcinogenic effects of aflatoxin. Thanks for the great videos you post!

  • Bruno

    Dr. Greger, you make my day. It is so refreshing to listen to someone with common sense contributions re. nutrition.
    Thank you!,
    You make a difference for me.

  • John La Puma MD

    Powerful piece: I wonder if the results would hold true if leafy green vegetables (or those densest in chlorophyll) were fed to subjects, instead of the isolated compound. Ditto for the aflatoxin.  

    Because of the complex interactions, it’s possible that green vegetables with less chlorophyll and more of a different detoxifier would have a more neutralizing affect.  Real foods are harder to study than the compounds we think are active…but ulitimately, it’s what people eat!  

    Keep up the great work.JL

  • R Ian Flett

    There are also studies showing that strongly pigmented foodstuffs like chlorophyll,   beetroot, turmeric, red grapes, etc., stain not only your shirt-front, but also selectively stain any cancer cells thus acting as markers and better attracting anti-cancer defences..This is a secondary benefit of strongly coloured plants.along with their higher antioxidant values.


    Now I can safely eat my aflatoxin

  • Peter Bell

    there is no way I am eating chloroform. that stuff is dangerous!

    • Gabrielle

      Chlorophyll and chloroform are not the same thing.

  • Simon

    is there any proof that liquid chlorophyl sold at health store is doing the same as the green ? any risks at taking it? some ppl at my work swear by it, and i find it kind of weird.

  • Gabrielle

    Were they taking capsules or eating a certain amount?

  • Francis Fong

    What about chlorophyll in an IV drip?

  • Mindaugas Raulinaitis

    What about the fact that vegan diet being rich in nuts in itself is a potential threat? Many studies conclude that the presence of aflatoxins in nuts (pistachios, almonds, cashews, of course peanuts) is a huge hazard for human health :( It’s scary that the incidence of molds, producing aflatoxins in nuts varies between 30% and as much as 91%, according to different studies.