Image Credit: Pulmonary Pathology / Flickr. This image has been modified.

How Tumors Use Meat to Grow

Certain cancers—like breast cancer—can be thought of in part as an autoimmune disease.

When people get heart or kidney transplants, they must be given immunosuppressive drugs to prevent rejection of the new organ. What do you suppose happens to cancer rates in those individuals who have their immune systems suppressed? Well, for some types of cancer, like skin cancer, the risk goes up. This supports the so-called immune surveillance theory—the idea that our immune system acts as a natural defense system for keeping cancer under control (see a cool video of immune cells taking on a cancer cell here). This could explain why, as we age and our immune function declines, our risk of cancer goes up.

The problem with the immune surveillance concept is that for some cancers, suppressing immune function decreases risk. After a kidney transplant, though your skin cancer risk may go up, your breast cancer and rectal cancer risk goes down. Why would people with depressed immune systems have less cancer? This led to a new theory of cancer I explore in my 4-min. video Cancer as an Autoimmune Disease.

The only reason the immune system is even able to pick out cancerous cells from noncancerous cells is because tumors express foreign looking molecules that stimulate our immune system. Why would tumors do that? Why would cancer cells go out of their way to wave a red flag around saying, “Hey, come get me!”? We think it’s because cancer tends to thrive in a setting of low level inflammation. In the video I show a number of examples of chronic inflammation leading to cancer–ulcerative colitis to colon cancer, chronic pancreatitis to pancreatic cancer, chronic hepatitis to liver cancer, and stomach inflammation to stomach cancer. Oftentimes the body’s inflammatory immune response can further cancer’s agenda.

By inciting an immune response, cancer creates its own inflammation, which may stimulate angiogenesis, the formation of new blood vessels to bring blood to the tumor and help it grow. This may explain the mystery surrounding Kaposi’s sarcoma, a cancer affecting those with AIDS. When you start treating AIDS and the immune system starts to recover you can actually see a flare in the cancer.

So what are the dietary implications of this new autoimmune theory of cancer? See my 3-min. video How Tumors Use Meat to Grow: Xeno-Autoantibodies. In short, there’s a molecule called Neu5Gc found in nonhuman animals but not made by the human species. Cancerous breast tumors appear to incorporate this molecule that women consume in meat and dairy to trick their immune systems into creating the environment of low-grade inflammation that breast cancer thrives in. Our own cancer may use what we feed on to get what it feeds on.

For more on Neu5Gc, one of the most fascinating topics of modern day nutrition, see my 4-min. video The Inflammatory Meat Molecule Neu5Gc.

Why else might those eating plant-based diets have lower risk of all cancers combined? Kathy Freston wrote a good summary. It could be due to diminished exposure to IGF-1heme ironinflammation, virusesantibioticssaturated fatnitrosamines, and arachidonic acid associated with animal product consumption. Or it could be the DNA repair,cellular stress defensesanti-inflammatory properties, soylignansphytonutrients, and fiber associated with healthy plant food consumption. It’s probably both, so it may not be enough to just eat vegan—we need to eat our veggies too.

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my videos for free by clicking here and watch my full 2012 – 2015 presentations Uprooting the Leading Causes of Death, More than an Apple a Day, From Table to Able, and Food as Medicine.


Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.

16 responses to “How Tumors Use Meat to Grow

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  1. A fantastic recap of how dietary lifestyles engender cancers.

    I haven’t posted in awhile but that doesn’t mean I’m not out there reading your great work!
    Keep it up!

  2. Very interesting, indeed.

    Inflammation and autoimmune conditions both can be extremely debilitating. I have been struggling with chronic inflammation/lupus in my head area for the past few years. I’ve been a vegan for the past few years, and it has definitely helped the flare ups. But the inflammation is still there, even if not as pronounced all the time.
    Does anyone know of ways that I can get some relief or maybe even remedy the condition? Are there particular foods or treatments I should focus on?

    1. Usually if you eat the foods that our body is evolved with, in the long term at least, these conditions tend to diminish or vanish.

      Our body will tell you what IT has evolved with via the gustatory sensors. If you like it RAW, that’s it. If you don’t, masquerading it with cooking, spices, fermentation and so forth won’t help.

      In your specific case though, in the short term, you could have a look at those foods that are anti-inflammatory (e.g. generally greens, pineapple, guava, kiwis) as opposed to the inflammatory ones (e.g. dates, bananas, oranges, potatoes, grains, squash, pumpking etc.) which you could try to avoid.

      Hope it helps.

    2. Dr. Joel Fuhrman has had considerable success with reversing autoimmune disease through supervised fasts. The body seems to forget its self-conflicts in the process. Don’t remember the name of his book re this. Google his books. Eat to Live is a great book, too.

  3. Dr. Greger First you are a god among men second as a new subscriber I want to thank you for providing us long standing vegheads with data that substantiates what we knew or suspected all along. That chronic diseases are exacerbated by meathead diets incompatible with our original (plant consuming) biological makeup. I always recommend your Uprooting the Leading Causes of Death video to anyone open minded enough to look at the evidence. Many thanks, Martha Helene Jones

  4. Well, consider all angles. For ex if a cat has cancer, you can’t withdraw meat as a treatment, because the cat is subject to going completely blind if it’s taurine deprived. Healthy cells also need protein. You can eat meat in moderation and take boswellia for anti-inflammation, if absorbs better than curcumin, even if piperine is added to curcumin. I wouldn’t count on giving a cat a taurine powder supplement after withdrawing meat because other amino acids may be needed for taurine uptake. In my experience, the thing that stood out like a miracle for my personal health was simple—I’d drink the juice of a lemon in plain water, no sweeteners added, twice daily on empty stomach. This reversed the risky calcified arterial condition I had. Of course I stayed on this daily for six months and thereafter juice one lemon per week. This diluted lemon juice must not be allowed to remain on the teeth longer than two minutes—it will strip enamel off teeth, that should suggest the benefits internally where calcium is unwanted. It will work better than EDTA as it only attacks calcium in the circulatory vessels. It removes it faster than pomegranate and vitamin K-2 combined. Those you can take with meals away from the lemon/water.

  5. I was a strict vegetarian on a natural unprocessed diet and got life threatening colon cancer. My entire diet was nothing but whole grains and produce . restricting meat does not always lower cancer risk. Cancer risk also comes from prescription drugs like statins which are made up of carcinogenic aromatic hydrocarbons!

  6. Hi, I am very confused about which diet to follow. At the moment I am following a paelo diet that claims the same results and effects your vegan diets makes. I have been on this diet for 2 weeks and have lost a bit of weight cutting out sugar, all processed carbs and grains and alcohol. I have been eating a variety of veg and some fruits plus the recommended fats from grass fed free range animal, eggs, organ meat, cooking with coconut oil and using olive oil cold. I am very allergic to nuts so that is not an option which is why I did not choose a vegan diet to follow but I am concerned about eating so much meat and fats. What are your options about a paelo diet? They make the same health benefits you have mentioned in your video. I want to pursue the right diet for optimum health.

  7. I’m glad you’ve found this website which can help you learn more about the best diet using research not marketing gimmicks. It can be confusing when there are all sorts of claims out there about the best diet–not supported by any evidence. I think you might want to start with a few introductory videos confirming that learning about the best diet is important and how to go about doing just that. Please check out these videos taking a broad look at healthy nutrition:

    Then you can focus on both the paleo diet and a healthier option focusing on plant-based whole foods

    ‘Don’t want to overwhelm you, but there are some basic concepts you need to understand.Viewing some videos such as Folks Over Knives (available through most libraries) and reading How Not to Diet by Dr. Greger will provide full explanations so you can choose the best nutrition plan.Then keep viewing this website to learn more…

  8. My Name it’s George three years ago I was diagnosed with Carcinoid Tumor on the wall of my right trachea airway I was a big meat eater and I just switch the next day after the results to a raw vegan for one month then to normal plant base thinking maybe I can stop that tumor or reverse , but after three years still there it’s stable it’s not growing. I need some help I heard if my body produse extra serotonin it trigger this tumor to grow I’m looking at the food and I get confused cus I don’t know wich food to avoid and wich food it’s good.
    With help from God and some knowledgeable people I’m sure I will be good.
    Thank you!

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