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Plant-Based Prevention

Phytonutrients may in part account for the benefits of whole plant foods in cancer prevention.

August 21, 2007 |
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Supplementary Info

Sources Cited

M. C. Hughes, J. C. van der Pols, G. C. Marks, and A. C. Green. Food intake and risk of squamous cell carcinoma of the skin in a community: The nambour skin cancer cohort study. Int. J. Cancer, 119(8):1953-1960, 2006.

J. E. Cade, V. J. Burley, and D. C. Greenwood. Dietary fibre and risk of breast cancer in the uk women's cohort study. Int J Epidemiol, 36(2):431-438, 2007.

W. H. Xu, Q. Dai, Y. B. Xiang, G. M. Zhao, Z. X. Ruan, J. R. Cheng, W. Zheng, and X. O. Shu. Nutritional factors in relation to endometrial cancer: A report from a population-based case-control study in shanghai, china. Int. J. Cancer, 120(8):1776{1781, 2007.

E. T. Chang, V. S. Lee, A. J. Canchola, C. A. Clarke, D. M. Purdie, P. Reynolds, H. Anton-Culver, L. Bernstein, D. Deapen, D. Peel, R. Pinder, R. K. Ross, D. O. Stram, D. W. West, W. Wright, A. Ziogas, and P. L. Horn-Ross. Diet and risk of ovarian cancer in the california teachers study cohort. Am. J. Epidemiol., 165(7):802{813, 2007.

G. L. Austin, L. S. Adair, J. A. Galanko, C. F. Martin, J. A. Satia, and R. S. Sandler. A diet high in fruits and low in meats reduces the risk of colorectal adenomas. Journal of Nutrition, 137(4):999, 2007.

McCann SE, Kulkarni S, Trevisan M, Vito D, Nie J, Edge SB, Muti P, Freudenheim JL. Dietary lignan intakes and risk of breast cancer by tumor estrogen receptor status. Breast Cancer Res Treat. 2006 Oct;99(3):309-11. Epub 2006 Mar 16.

Grivetti, Louis E. PhD; Corlett, Jan L. PhD; Gordon, Bertram M. PhD; Lockett, Cassius T. PhD. Food in American History Food in American History: Part 10. Greens: Part 1. Vegetable Greens in a Historical Context Nutrition Today: March/April 2007 - Volume 42 - Issue 2 - pp 88-94.


Image thanks to Ted Major.


Skin cancer. You know how there’s like good skin cancer and bad skin
cancer? This aint the good kind. Two and a half times the risk if you eat dairy—
milk cheese yogurt, but they did find something so incredibly powerful as to cut
cancer risk about 50%??? Yes, greens! Eat dark green leafy vegetables and cut
your risk in half!. Yeah, but how many greens did these poor women have to eat?
Well, here’s the data. These are the women that ate the most greens and had
half the cancer risk of these women who ate the least greens, averaging only 6 grams of greens a day. That’s the weight of 6 paper clips. They must have like accidentally ate the garnish—some sprig of parley next to their steak or something. OK, but what about the highest tier of greens intake cutting their squamous cell skin cancer risk in half? 31 grams of greens day. 31 paper clips. That is the equivalent of just 3 leaves of spinach. Count them one two three leaves a day. Half the risk of skin cancer. That’s how powerful greens are. Eat your greens, every day. In fact this year there was even a review of greens in American history. General George Washington, in 1777 gave the general order that American troops go out and pick their wild greens growing around their camps to protect them from “all putrid disorders.” This is from Thomas Jefferson’s garden diary.

Beans, broccoli, kale. These were smart men. Then they looked to the future of greens. How are we going to feed astronauts on flights to Mars? According to NASA, on a… plant based diet. “For the majority of the journey to the red planet… the astronauts would be vegetarians.” Figs in space. Just as eating meat increases your risk of cancer; eating plants decreases your risk. Eating a lot of plant foods could cut your risk of getting breast cancer in half. Dietary fiber. Remember fiber is only found in plant foods. Animals have bones to hold them up; plants have fiber to hold them up. But only unrefined plant foods—white flour, white bread, white rice, white pasta: they take
all the fiber away. Eat whole plant foods. Same with endometrial cancer. Lots of animal protein and animal fat, you get nearly twice the risk; lots of plant protein and plant fat nearly half the risk. Another huge study. Journal of the National Cancer Institute. More plants; less cancer. Why? Dietary lignan intake. Lignans are one class of thousands of compounds called phytonutrients. Phyto- means plant—these are special plant
nutrients. Best source of lignans on the planet??? Yes, Flax seeds. 97,000 women studied. Ovarian cancer. Lots of isoflavones and cut your risk in half. Ovarian cancer is a horrific cancer. What’s the top source of isoflavoes. Yes, soy foods. No brainer—high fruit, low meat prevents tumors. Duh. This is not just me being selective—I have for years challenged anyone to find me a single study showing more cancer on a plant-based diet. As far as I can tell such studies just don’t exist.

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.

To help out on the site please email

Dr. Michael Greger

Doctor's Note

Please feel free to post any ask-the-doctor type questions here in the comments section and I’d be happy to try to answer them. And check out the other videos on cancer. Also, there are 1,449 other subjects covered in the rest of my videos--please feel free to explore them as well!

For more context, check out my associated blog posts: Stool Size and Breast Cancer Risk and Breast Cancer and Diet.

  • Matt Wendt

    Plant-Based Prevention

    • Michael Greger M.D.


  • Michael Greger M.D.

    Please feel free to post any ask-the-doctor type questions here in the comments section and I’d be happy to try to answer them. And check out the other videos on cancer. Also, there are 1,449 other subjects covered in the rest of my videos–please feel free to explore them as well!

  • SuperNurse

    Why did the Veggie bacon in the diagram show to have saturated fat? Although it was only 0.2g, I thought that saturated fat only comes from animal based products?

    • Toxins

      This is not entirely accurate. Trans fat is the only natural fat found in animal products, specifically beef and dairy. Saturated fat is also found in nuts and seeds but is in much higher concentrations in animal products.

  • wickedchicken

    I eat a LOT of spinach. But, I use those pre washed, ready-to-eat bags. Now I hear that these could have no antioxidants left due to the pre-wash solution??? Devastating, as I am so lazy and hate washing spinach [always end up crunching grit!]. Whatdya think doc?

  • Ccj5036

    Four years ago I had a small skin cancer (basal cell) removed and was told to use a lot of suntan lotion and that I would possible have a reoccurrence within five years. I have been avoiding the sun ever since, trying to never spend more than a few minutes in the sun without lotion on. Fifteen months ago we switched to a plant-based, no added fat diet and I have been wondering about lack of sun exposure and Vitamin D3. Does the plant based diet give me a “get out of jail free card” so that I don’t need to worry about a few minutes of sun exposure each day? Any studies on vegans and skin cancer?

  • Traportka

    Please help, please.  My son, 14.5 yrs old has Crohn’s.  I am trying to slowly fade out of the SAD, Standard Amer. Diet, and introduce a semi-vegan.  Everytime I research it, I get bits and pieces of the info. and then a lot of tapes and books to buy.  Our budget doesn’t allow for me to indulge much, if at all.  How do ,I not only learn quickly, but teach two teenagers how to eat healthy when they are literally hungry all of the time?  I grew up on the SAD, so I am a bit behind the 8 ball on this one.  With that being said, I’m eager to learn for the sake of my boys.   My biggest dilemna is they both go to boarding school and are literally living on processed food 4 days out of the week.  I have resolved to supply them with their food for the week with homemade whole food.  Where and how do I begin?

    • WCabrera

      I’m so sorry to hear about your son’s diagnosis!  You are in a great place to get help.  I’d highly suggest hunkering down and watching all of these videos and read the blogs.  You will educate yourself and learn how to care for your son quickly. When you’re in a crisis, nothing is too difficult.  I’d highly suggest cutting out ALL fast food with no exceptions.  If it does not grow in the ground, don’t eat it.

      Another resource that will help you in your quest to heal your son of Crohn’s is  He has some specific protocols for Crohn’s patients.  It’s tricky.  

      The inflamed bowel desperately needs the phytonutrients to heal from the very thing that causes them to react.  BUT….it will work.  Join his member board and ask him directly AFTER you read his book, Eat to Live.

      There is much hope. 

      Keep your head down and move forward!  What seems so foreign now will be second nature soon, and your son will be living a thriving, healthy life!


      • Traportka

        WC, it was very kind of you to take the time and share your knowledge and this info.  Can’t thank you enough or tell you how much I appreciate it, but I really do. 
        Thank you for the blessings.  I’ll make sure I pass it on  : )

  • green smoothie lass

    I blend & drink many green veggies & fruits daily. Can you please recommend the best way to ensure the greens are free of harmful bacteria (just read that raw greens are responsible for half the cases of food borne illness-can’t imagine rinsing is effective on bacteria hiding in the nooks & crannies of curly kale) and advise as to the possibility of thyroid damage from too many oxalates. How much is too much kale/spinach/chard?
    Also–is the blackberry gel used in oral cancer studies available or purchase? Thank you.

  • Ram

    hello Dr.
    Hope you are doing well.
    I would like to have your comments on herbal treatment of poly cystic ovarian syndrome

    • Don Forrester MD

      It has been several years since I did an educational presentation involving nutrition and PCOS so I did a brief pub med search. It is a complex and fairly common syndrome. Not much has changed. Insulin resistance is an important aspect of PCOS and the best approach is a low fat diet… eliminate animal products because that is where patients typically get 80% of their fats but also plant fats such as processed oils. It is the fats that interfere with the insulins ability to get glucose into the cells and also down regulate genes interfering with the mitochondria’s ability to metabolize glucose. Low fat diets also increase steroid binding globulin in the blood thus lowering free hormones. High fiber diet also helps remove steroids from the gut so they are not reabsorbed into the body. Phytosterols and fiber seem to be a helpful factor as well. I would suggest you review the four videos on fiber and phytosterols beginning on August 13 with Higher body fat is associated with worsening of PCOS. Fat loss is best accomplished by reducing your diets Calorie Density. For fat loss I recommend two resources. The DVD by Jeff Novick called Calorie Density: How to Eat More, Weigh Less and Live Longer and the presentation by Dr. Doug Lisle, How to Lose Weight without Losing you Mind, can view for free on internet, I would emphasize a sound nutritional approach before using medications. I am not aware of any herbal remedies which are supported by sound peer reviewed scientific articles.

  • Ruben

    Can hypothyroidism be reverse with plant-based diet (the type of Hashimoto’s or autoimmune)