Why the Egg Cancer-link?

Image Credit: Christopher Craig / Flickr. This image has been modified.

Why the Egg-Cancer Link?

Two million men in the U.S. are living with prostate cancer — but that’s better than dying from prostate cancer. Catch it when it’s localized and the five-year survival is practically guaranteed, but once it really starts spreading, chances drop to one in three. “Thus, identification of modifiable factors that affect the progression of prostate cancer is something that deserves study,” noted Dr. Erin Richman and colleagues at Harvard. So, they took more than a thousand men with early stage prostate cancer and followed them for a couple years to see if there was anything in their diet associated with a resurgence of the cancer, such as spreading to the bone.

Compared to men who hardly ate any eggs, men who ate even less than a single egg a day had a significant 2-fold increased risk of prostate cancer progression. The only thing worse was poultry consumption, with up to four times the risk of progression among high-risk men. They think it might be the cooked meat carcinogens that for some reason build up more in chicken and turkey muscle than in other meats. For more on these so-called heterocyclic amines, see my videos: Heterocyclic Amines in Eggs, Cheese, and Creatine?, Estrogenic Cooked Meat Carcinogens, and PhIP: The Three Strikes Breast Carcinogen.

But what about the eggs? Why would less than once-a-day egg consumption double the risk of cancer progression? “A plausible mechanism that may explain the association between eggs and prostate cancer progression is high dietary choline,” the researchers suggested.  Egg consumption is a determinant of how much choline you have in your blood, and higher blood choline has been associated with a greater risk of getting prostate cancer in the first place. So the choline in eggs may both increase one’s risk of getting it and having it spread.

Studies have associated choline consumption not just with getting cancer and spreading cancer, but also with significantly increased risk of dying from it. Those who ate the most had a 70% increased risk of lethal prostate cancer. Another recent study found that men who consumed two and a half or more eggs per week — that’s just like one egg every three days — had an 81 percent increased risk of lethal prostate cancer.

Maybe that’s why meat, milk, and eggs have all been associated with advanced prostate cancer—because of the choline. Choline is so concentrated in cancer cells that doctors can follow choline uptake to track the spread of cancer throughout the body. But why may dietary choline increase the risk of lethal prostate cancer? Dietary choline is converted in the gut to trimethylamine (see my video Carnitine, Choline, Cancer and Cholesterol: The TMAO Connection), so the Harvard researchers speculated that the TMAO from the high dietary choline intake may increase inflammation, which may promote progression of prostate cancer to a lethal disease.

In one of my videos, Eggs and Choline: Something Fishy, I talked about what trimethylamine might do to one’s body odor.

In the New England Journal of Medicine, the same Cleveland Clinic research team that did the famous study on carnitine repeated the study, but instead of feeding people a steak, they fed people some hard-boiled eggs. Just as they suspected, a similar spike in that toxic TMAO. So it’s not just red meat. And the link between TMAO levels in the blood and strokes, heart attacks, and death was seen even in low-risk groups like those with low-risk cholesterol levels. Thus, because of the choline, eating eggs may increase our risk regardless of what our cholesterol is.

It’s ironic that the choline content of eggs is something the egg industry actually boasts about. And the industry is aware of the cancer data. Through the Freedom of Information Act, I was able to get my hands on an email (which you can view in my video, Eggs, Choline, and Cancer) from the executive director of the industry’s Egg Nutrition Center to an American Egg Board executive talking about how choline may be a culprit in promoting cancer progression. “Certainly worth keeping in mind,” he said, “as we continue to promote choline as another good reason to consume eggs.”

 

With regard to the prevention of prostate cancer progression, chicken and eggs may be the worst foods to eat, but what might be the best? See my video Prostate Cancer Survival: The A/V Ratio.

To prevent prostate cancer in the first place, see videos such as:

What about reversing cancer progression? See Dr. Ornish’s work Cancer Reversal Through Diet?, followed up by the Pritikin Foundation: Ex Vivo Cancer Proliferation Bioassay. Flax may help as well (Flaxseed vs. Prostate Cancer).

-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.

Discuss

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.


23 responses to “Why the Egg-Cancer Link?

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    1. KWD: Thanks for that link.

      Sam: I can provide a little more info on the topic. A good reference book for our nutritional needs is the book, “Becoming Vegan, Express Edition” By Brenda Davis and Vasanto Melina. They did a *ton* of research to write that book, and they have a lot of experience behind them.

      Here is a quote from the book concerning choline:
      “Choline has hopped back and forth across the line between vitamin – and therefore essential – and nonvitamin. That’s because the body can produce sufficient choline unless a person’s diet is short on folate, vitamin B12, and the amino acid methionine. People seem to need significantly different amounts depending on genetics and diet.”

      You can learn more about the topic by reading the book itself. I just wanted to share that really interesting bit. I interpreted the above to mean: As long as you are generally healthy and eating a healthy diet, you don’t have to worry about choline intake.

      Dr. Greger does not appear to be particularly concerned about focusing on choline intake. Here are Dr. Greger’s nutritional recommendations. Notice the lack of concern about choline for people on a Whole Plant Food Based Diet:

      http://nutritionfacts.org/2011/09/12/dr-gregers-2011-optimum-nutrition-recommendations/




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  1. fish also contain choline. However reports say if u dont eat fish u double the risks of dementia.

    Maybe that why Previously choline has been touted as brain food !




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    1. Peter Smith: I know there are articles out there that say that fish is good for the brain. But the overall science does not seem to support this theory. Here is an example report from PCRM:

      “Fish Oil Supplements No Help to Heart or Brain

      Two new studies found that omega-3 supplements, often sold in the form of fish oil, do not improve the health of the brain or heart.
      After following more than 12,500 type 2 diabetes patients over the age of 50 for an average of 6.2 years, researchers saw no difference in heart health between those taking an omega-3 supplement versus a placebo. Diabetes patients are two to four times more likely to suffer from heart disease or a stroke, compared with people without diabetes. Another recent meta-analysis came to the same conclusion for people with a history of heart problems.
      Additionally, in a new review looking at omega-3 supplementation for brain health, researchers found no link between omega-3 supplements and the prevention or improvement of dementia.
      Bosch J, Gerstein HC, Diaz R, et al. n–3 fatty Acids and cardiovascular outcomes in patients with dysglycemia. N Engl J Med. Published online June 11, 2012.

      Kwak SM, Myung SK, Lee YJ. Efficacy of omega-3 fatty acid supplements (eicosapentaenoic acid and docosahexaenoic acid) in the secondary prevention of cardiovascular disease: a meta-analysis of randomized, double-blind, placebo-controlled trials. Arch Intern Med. Published ahead of print, April 9, 2012.

      Dangour AD, Andreeva VA, Sydenham E, Uauy R. Omega 3 fatty acids and cognitive health in older people. Br J Nutr. 2012;107:S152-S158.”

      Also, if you read Dr. Barnard’s book, “Power Foods For The Brain”, you can see that he does not recommend eating any fish. (He explains why.) I’ll also refer you to my reply to Sam previously on this page. The Becoming Vegan book mentions that lots of plant foods are also rich in Choline. My take-home message is: there really is no need to eat fish, most especially if you are concerned about your brain.




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      1. I don’t think one should use data about omega-3 supplements to argue a point about eating fish. Various studies have shown omega-3 supplements do not “track” fish-eating results e.g. as reported in the Berkeley Wellness Letter v30, issue 13, July 2014 in summarizing the findings of the recent meta-analysis on fat intake that’s caused such a stir, fish-eating but neither omega-3 supplements or plant-provided ALA is associated with lower coronary risk. The two studies you cite refer to omega-3 supplements, not fish eating.




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    2. Choline is the precursor to acetylcholine, one of our primary ‘thinking’ neurotransmitters. There are many individuals who supplement choline in a variety of forms (Alpha-GPC, Citicoline, and phosphatidylcholine) to increase cognition. Acetylcholine deficiency is linked to Alzheimer’s disease.




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  2. I’m always suspicious of these correlation studies. Maybe it’s something else in eggs, rather than the choline, that causes prostate cancer.

    As it turns out, there is: Egg yolks contain a lot of arachidonic acid, of which the body rids itself by producing a dangerous enzyme called 5-lipoxygenase (5-LOX), and 5-LOX directly stimulates prostate cancer cell proliferation.

    In addition, arachidonic acid is metabolized by 5-LOX to 5-HETE, which prostate cancer cells use to escape destruction. See: http://www.lef.org/magazine/mag2007/feb2007_cover_prostate_01.htm

    Fortunately, there’s an Ayurvedic herb — boswellia serrata — which is sold under various trade names, one of which is “5-Loxin” — that helps to counteract the dangerous effects of 5-LOX. If one has prostate cancer, this particular herb may be worth considering in addition to eliminating egg yolks from one’s diet.




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    1. Egg whites are only water,protein,sodium,selenium.Nothing wrong with egg whites.All the (possible dangers) are with the yolk.If you wanna consume just eggs from the animal byproducts then go only with the egg white.




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      1. Heisenberg: The devil is in the details. That protein you mention is animal protein, and one that is particularly linked to cancer risk through it’s high methionine content (the highest). Here is some info on methionine.
        http://nutritionfacts.org/?s=methionine

        So, there are at least two known mechanisms (the first being IGF-1 which Rami mentions above and links to more info) by which egg whites raise the risk for serious disease. There’s the rub.

        As Dr. Barnard says, there are only two problems with eggs, the yolk and the white.




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    1. Most organic/free range operations use the same breeds, which have been bred to grossly overproduce eggs. “Real” hens live in the jungle and produce about 15 eggs a year. And I don’t know if any of this affects choline amounts.




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  3. The study sited here (“Choline intake and risk of lethal prostate cancer: incidence and survival”) does not explicitly say how the men with the “highest quintile of choline intake” obtained their choline, although it strongly implies that they got it strictly by eating “Meat, milk, and eggs”. To say that choline is the reason for their being in the ‘highest quintile’ requires a study involving supplemental choline intake alone, rather than getting choline from meat, milk and eggs, which contain a lot more than just choline.

    For me, it won’t make any difference. I intend to continue taking supplemental choline as it is the only nootropic substance I take that noticeably improves my memory. If doing so increases the risk of prostate cancer, the thing to do is to also supplement with Vitamin D3 and Saw Palmetto and other substances that decrease the risk of prostate cancer. In any case, going around in a choline-deficient stupor for the rest of my life is definitely worse than shortening it by a few years via prostate cancer.




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    1. Hi Dean,

      I am a volunteer for Dr. Greger. Thanks for your question. Cancer may be the most difficult disease to show causality for. While cohort studies (the ones analyzed by the papers you cited) are very useful, they can also be very limiting. Only after seeing a consistent change over a long period of time can we begin to conclude that something causes cancer.

      Only time and further research will tell, but food is a package deal (eggs contain vitamin D, vitamin B-12, selenium, lutein, etc., but also contain animal protein, cholesterol, and saturated fat). Lifestyle choices may also have mixed outcomes on our health. For example, smoking actually prevents Parkinson’s disease, but obviously increases cancer and heart disease risk. Perhaps eggs are in the same boat–they may decrease certain cancers, but increase others. Ideally, we should only be putting foods in our mouths that have little to no harmful nutrients in them, and have little to no negative influence on our health. Therefore, it is hard to make the argument for eggs as part of an optimal diet.




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    1. I am a moderator for NutritionFacts.org and want to comment on your question: Are egg whites okay? While some plant-based physicians okay egg whites, you are better off to avoid eggs in their entirety, whites and all. Egg whites are still very much animal protein. While there are many NutritionFacts.org videos on eggs you can view, I think the following one which mentions Eggbeaters (mostly egg whites) clarifies the point; https://nutritionfacts.org/video/antioxidant-power-of-plant-foods-versus-animal-foods/




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  4. I eat about 4 dozen raw eggs a week. I guess I really should watch out for prostrate cancer? I have done this for several years. I am 61 years.




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  5. Garry- If you are serious about wanting to minimize your risks, you really need to focus on the research and how the consumption of that many eggs is so clearly associated with prostate cancer (not to mention the contamination risks from raw eggs). Because you have not experienced negative consequences yet does not make you immune; it may just mean your body has managed to escape the consequences so far. Why test your luck? Again use the SEARCH bar to read about health risks of eggs– then can surely answer your own question about watching out for prostate cancer.




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