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Bad Egg

In 2008, the Harvard Physician’s Health Study, which followed about about 20,000 physicians for 20 years, found that those eating just a single egg a day or more had significantly higher total mortality risk, meaning eating just one egg a day was significantly associated with living, on average, a shorter life. Later that year, that same single serving of egg was significantly associated with death and hospitalization from heart failure.

In 2009, it was diabetes. We’d known how bad eggs were for people with diabetes (doubling their risk of death), but it wasn’t until “Egg Consumption and Risk of Type 2 Diabetes in Men and Women”—another Harvard study—that we learned how much eating eggs increases our risk of getting the dreaded disease in the first place. Compared to those eating less than an egg a week, men eating just one a day appear to raise their risk of developing type 2 diabetes 58%, and women, 77% more risk.

That’s all old news I’ve covered before (here and here). What’s the latest? Well, whereas the twin Harvard death and diabetes studies followed mostly middle-aged men and women in their early 50s, the Health, Aging and Body Composition Study, published this summer, found that the risk associated with eggs extends well into one’s seventies. And if eggs raise one’s risk of type 2 diabetes so much, what about gestational diabetes, the loss of blood sugar control affecting up to 1 in 10 pregnancies? It was apparently never researched until this year, when a new study found that women eating one egg a day or more doubled their odds. “In conclusion,” the researchers write, “high egg and cholesterol intakes before and during pregnancy are associated with increased risk of gestational diabetes mellitus.”

The most important study, though, was a landmark review published last fall. It is the subject of my video-of-the-day both today and tomorrow. On Friday I’ll continue the theme of science scrambled by the egg industry. Yesterday’s video-of-the-day concerned the dairy industry’s attempt to mislead the public about milk and mucus. S’not as bad as the egg industry trying to downplay the risks of cholesterol, though, with egg consumption now tied to diabetes, heart failure, and premature death.

-Michael Greger, M.D.


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.

42 responses to “Bad Egg

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  1. Not to mention the 100,000+ Americans poisoned by Salmonella-tainted eggs every year. See the Des Moines Register investigation this week on what our government continues to hide from us about last year’s recall of more than a half billion eggs.

      1. I have been vegan for 9+ years and am almost finished with your book, I’ve tweaked my diet a little to aim for the daily dozens, but I want to make sure I’m avoiding what I need to avoid & ingesting what I need for when I get pregnant.

  2. I have recently read that there is a difference between commercial eggs and farm eggs — I have six chickens that roam freely, and I use the eggs for cooking, for the occasional breakfast, and even for a dinner at least once a week. Am I wrong to think my eggs are healthier? Thanks!

    1. I will let Dr. Greger comment on your question, but in my view, the answer is no, you are not wrong.

      Not all eggs are created equal.

      I had bookmarked from when I used to eat eggs this very interesting article on Mother Earth News:

      “Our testing has found that, compared to official U.S. Department of Agriculture (USDA) nutrient data for commercial eggs, eggs from hens raised on pasture may contain:

      • 1⁄3 less cholesterol• 1⁄4 less saturated fat• 2⁄3 more vitamin A• 2 times more omega-3 fatty acids• 3 times more vitamin E• 7 times more beta carotene ”

      Also, I found a link to full research document on the benefits of pastured eggs:

      Vitamins A, E and fatty acid composition of the eggs of caged hens

      1. My reaction to “1⁄3 less cholesterol” was: “That means that it still has 2/3 the cholesterol of an abused hen’s egg! and isn’t 2/3 amount of cholesterol still quite significant?” Or not?

        Similarly at: “2 times more omega-3 fatty acids• 3 times more vitamin E• 7 times more beta carotene” I think those numbers would only be significant if battery eggs had enough say omega-3’s worth talking about. In other words, 2 times almost zero is still almost zero. I don’t know how much omega-3s battery eggs have. I’m just saying that “better” (pasture egg vs battery egg) is not same thing as “good”/healthy.

    2. That may be true of pasture-raised birds, but a new study published this summer found no significant difference between cholesterol levels in “free-range” compared to conventional eggs (over 200mg per jumbo egg in each case). Free-range eggs are certainly better from an animal welfare standpoint, and also less likely to be contaminated with Salmonella (the leading cause of food-borne illness related death in the United States), but don’t appear to have less cholesterol, the most important health reason to minimize one’s egg intake.

      1. Thanks for clarifying Dr. Greger, I just wanted to jump in and point out that “free-range” eggs are not better in terms of animal welfare. If you have chickens as pets and harvest their eggs, that’s one thing, but “free-range” simply means they’re tortured in a barn before being slaughtered instead of being kept small cages. It’s still disgusting exploitation and none of it is morally acceptable. A topic many don’t want to think about, but I feel it really drives the nail into the coffin for the egg argument. Veg on.

  3. Very helpful blog, Dr. Greger. I would find it helpful if the increased risk were put into context against a quantified baseline risk (“baseline risk” being my own non-scientific term). For example, if one egg per day raises “risk of [men] developing type 2 diabetes 58%, and women, 77% more risk,” what are the risks of type 2 with an egg-free diet? Thank you!

    1. If you look at the study (available free, full text), you’ll see that diabetes risk depends on a number of factors, including your age, weight, smoking status, alcohol consumption, exercise, meat intake, fruit and vegetable intake, saturated fat intake, trans fat intake, polyunsatarated fat intake, your family history of diabetes, and a medical history of high cholesterol or high blood pressure. So there’s no “one” level of risk. However, even after all those factors were taken into account and controlled for there was still a significant increase in risk for those eating eggs. So whatever other risk factors you have, reducing your consumption of eggs would be expected to further reduce your risk.

  4. I had read the article in Mother Earth, I think. I’ll check out the other one. And I do hope to get a response from Dr. Greger as well!

  5. Your information about eggs is very clear to me. However, I was discussing eggs with my mother the other day and she told me that the news said that they have discovered that eggs do not really have all that much cholesterol after all. What do I say to that? Is she referring to a flawed study? An idea to think about: Could you do a video that shows the recent headlines about eggs being healthier than previously thought and then address that? I saw today’s video of the day and it wasn’t clear to me whether or not you were addressing this particular issue. You mention lobbies by the egg industry, but it wasn’t clear to me that you were addressing the new latest study that supposedly showed that eggs do not have as much cholesterol as previously thought.

    A question: suppose I am able to get an egg from a humane source and from a chicken that eats a natural diet. Then, I make a meringue cookie – using only the egg whites. From a health stand point, do we know if there are problems with the egg while, or is it only the yolk?


    1. It is true that the latest USDA Nutrient survey found that eggs appear to have less cholesterol (by 14%), but that’s like all these junk food companies bragging “Now with 20% less sugar.” Junk food with 20% less sugar is still junk food (check out the gall of this). For more on misleading food practices, check out this recent editorial in the Journal of the American Medical Association co-written by one of my heroes, Marion Nestle.

      1. Thank you so much for your reply. That REALLY puts it into perspective. I will be sharing this with my mother.

        It helped me too. I hadn’t realized that it was only 14% less cholesterol. That’s nothing when the original number was so very high.

        1. Yes, it’s important in so many cases to qualify the information we’re gleaning, especially from “news” sources who may be throwing a story out there as prompted by the very industry who wishes to misinform (eg.; the egg-producing industry). As was stated earlier in another response here, one jumbo egg has 200mg of cholesterol. So, doing the math, 14% less would put that same jumbo egg (provided the figure of 14% was derived from the same size egg….see what I mean by qualifying?) at 172mg of cholesterol -still a significant amount from just one source (egg), in my estimation.

  6. I am not a scientist. Reading this article, the first question that sprung to my mind was: How do you know it was the egg that was respondible for increased mortality/risk of diabetes, etc? There could be so many other factors, eg genetics.
    I keep pet chickens. They are free range, have names and lay wonderful eggs which do not compare in any way to the supermarket egg from a battery chicken.
    I really feel that the eggs I use are healthy and think it is a case of all things in moderation.
    I am sure I read a while ago that the type of cholesterol in eggs is good cholesterol. Every new scientific paper seems to cancel out what was stated emphatically in the previous one.
    I think the only thing we can do is apply common sense. :)

    1. You are absolutely right that there are lots of other risk facts (see my reply to jcchavez above). They are able to control for all those listed factors, though, and focus in on the egg consumption. Did they control for everything? No, but Harvard has an excellent record of doing some of the best epidemiology (population-based) research in the world.

      In terms of the free-range issue and health (yours, not your darling pets!), please see my response above to Benjamin.

      And there is no “good” or “bad” cholesterol in foods; it’s all bad (i.e. all in excess of what your body needs). When you hear doctors talk about good and bad cholesterol, they’re talking about protein complexes in your blood. The one that deposits cholesterol in your arteries is understandably called bad (LDL) and the one that removes the gunk is called good (HDL) and eating eggs not only increases your LDL (bad), but unfortunately does all sorts of other nasty things as mentioned in the video today.

      For more on cholesterol, see all the other two dozen or so videos here.

  7. Something for the people with “pet egg laying chickens” to think about: Where are the roosters? Baby male chicks are killed at birth because they are do not lay eggs, and when you buy chicks the hatcheries have already disposed of the male chicks. Also, do you intend to let the chickens live out their full natural lifespan? Did you realise that in the wild, chickens will eat their non fertilized eggs to regain the protein in them? Did you ever stop to think about how weird it is to eat what is essentially a chicken’s “period”? Why not try mixing ground flaxseed in a little water and using that as an egg replacer in baking instead?

    1. I find that a tablespoon of ground flax seeds to 3 tablespoons of water is a great cholesterol-free egg substitute. The secret though is that you whip it up together before you use it so it gets all gooey and “egg-like.” Then I’ve found it works great. Anyone else have any favorite egg replacers?

    2. Thanks for calling attention to the missing roosters. Many municipalities which allow folks to have have chickens don’t extend that invitation to the roosters, citing noise concerns.

  8. Heidi, our chickens are not pets; the only one we have named is the rooster, because he is so gorgeous: Black Beauty. He takes very good care of his hens. When he finds something good to eat, he calls them over, and lets them have it first. Our chickens, dogs, and cats all get along. Why on earth would I make an egg replacer when I have these delicious eggs?

  9. Let’s not forget that eggs can be consumed with or without the cholesterol rich yolk. Eggs can provide a very important and inexpensive source of highly bio-available protein, especially to those choosing a lacto-ovo vegetarian diet.

    Page 2 of the paper describes the survey question asked:
    Participants were asked to report how often, on
    average, they have eaten eggs (one) during the past year”. Possible response categories included
    “rarely/never”, “1-3/month”, “1/week”, “2-4/week”, “5-6/week”, “daily”, and “2+/day”. This
    information was obtained at baseline, 24, 48, 72, 96, and 120 months after randomization.

    There was no option for “I only eat egg whites” or “I do not eat egg yolks or whole eggs.”

    The authors go on to say:
    “…infrequent egg consumption up to 6 eggs per
    week was NOT [my emphasis] associated with MI, stroke, or total mortality in healthy US male physicians. In
    addition, consumption of 7 or more eggs per week was associated with a modest but significant
    increased risk of total mortality in this population.”

    I would argue there are very few Americans eating more than 6 eggs per week, on average, although I have yet to confirm this with the NHANES data. Please correct me if you know those stats.

    Also, the authors reported “the lack of detailed dietary questionnaire prevent us from
    controlling for energy and other major nutrients…” Energy intake, obviously, is a huge factor to consider.

    Lastly, they conclude their article with:
    “…our data suggest that egg consumption up to 6/week has no major effect on the
    risk of CVD and mortality and that consumption of 7+/week is associated with a modest
    increased risk of total mortality in US male physicians.”

    I am not paid by the egg or poultry folks, or anyone from the food industry, for that fact. I just wanted to point out that some readers may mistake your summary as “avoid eggs at all costs” when in reality, that is not what the research indicates. Egg WHITES from free-range and/or small-farm poultry farms are a reasonable, healthy and socially responsible choice — certainly much more so than eating factory farmed eggs, poultry, beef, pork, or fish — which is the main method of protein intake for the largest majority of Americans.

    1. Did you see my coverage of the latest review on the subject (part 1 and part 2), concluding that no one (that isn’t dying from a terminal illness or something) should be regularly eating eggs. It’s true the Physician’s Health Study did not have the statistical power to pick up a significant elevation in risk for eaten less than one egg a day, but from what we know about the effects of dietary cholesterol the ideal upper daily limit of intake is zero (same with trans fats). Having said that, you are absolutely right that there is no cholesterol whatsoever in egg whites.

  10. I also often hear about Salmonella infections from vegetables. The FDA estimates that only 1 in 20,000 eggs is infected.
    Dr. Greger, have you ever studied the history of the hypotheses that dietary saturated fat and LDL are heart health risks? These hypotheses are unproven. No study has shown that reducing LDL levels reduces the risk of heart disease (and I’m including the statin studies).

      1. No, they don’t is the short answer.

        Statin drugs were a dream come true for drug makers: they reduce LDL and they reduce the incidence of cardiac events/death. But that doesn’t prove statins work by reducing cholesterol.

        This is not nit-picking. It is accepted that statins have a “pleiotropic” effect, i.e. they have benefits that are not due to LDL reduction. If you go to a hospital ER complaining of chest pain they will probably immediately give you a statin (Lipitor?) because it has been shown it reduces the risk of plaque rupture. This has nothing to do with LDL reduction: statins take weeks to achieve this. Is it possible that this mechanism explains the benefit in the long term reduction of the incidence of cardiac events/death?

        It is generally claimed that the more one reduces the LDL the greater the benefit. The A to Z study disproved this for simvastatin, see It showed that the degree of LDL lowering has no impact on CHD.

        The benefits claimed for statins are always expressed as relative reductions. The absolute reductions are always small. This invariably means that the “Number Needed To Treat” is a very large number, ~100, which is very poor efficacy for a drug. It means most people taking it will get no benefit. Say for example a study shows that for every 100 people there will be 3 deaths without statin treatment in 5 years but with statins there will be 2 deaths. That is a 33% reduction. One of 100 will survive the 5 years with statins but would have died without. How long will he last after the 5 years. In terms of life expectancy statins add just a few days.

        As far as actually living longer, I think that has only been proved for men with a history of heart attack or unstable angina. There is little benefit from statins for women and none for women without a CHD history.

  11. The issue of cholesterol and lipoprotein fractions as an indicator of CHD risk if far from cut-and-dry:
    Please see:
    The Great Fat Debate: Taking the Focus Off of Saturated Fat
    Journal of the American Dietetic Association – Volume 111, Issue 5 (May 2011)
    Dariush Mozaffarian, MD, DrPH
    Here is an excerpt:
    “The Institute of Medicine (IOM) recently released a systematic review on the use of biomarkers as intermediate outcomes to infer effects on disease risk. For LDL cholesterol, they concluded that the “data supports the use of LDL as a surrogate end point for some cardiovascular outcomes for statin drug interventions,”—that is, if one is evaluating a statin, one can consider effects on LDL as sufficient to infer effects on some cardiovascular endpoints—“but not for all cardiovascular outcomes or other cardiovascular interventions, foods or supplements.” Thus, the IOM concluded that effects of foods on LDL cholesterol alone were not valid for use as a biomarker to determine effects on disease risk. The IOM report recommended that the US Food and Drug Administration (FDA) use the same degree of scientific rigor for evaluation of biomarkers across regulatory areas, including for foods. Based on this recommendation, it should no longer be sufficient to show that a food changes one biomarker—eg, cholesterol levels—and then use these data for a health claim. One really must also show evidence for effects on disease outcomes, in a similar manner as we now recognize we must do for drugs.

    The IOM report also concluded that we must take into account a nutrient’s food source and overall dietary patterns when determining health effects. Thus, focus on a single nutrient such as total fat or saturated fat and its effects on biomarkers, without considering the foods and dietary patterns consumed, can produce misleading conclusions.”

    Am J Clin Nutr. 2011 Apr;93(4):684-8. Epub 2011 Jan 26.
    The role of reducing intakes of saturated fat in the prevention of cardiovascular disease: where does the evidence stand in 2010?
    Astrup A, Dyerberg J, Elwood P, Hermansen K, Hu FB, Jakobsen MU, Kok FJ, Krauss RM, Lecerf JM, LeGrand P, Nestel P, Risérus U, Sanders T, Sinclair A, Stender S, Tholstrup T, Willett WC.
    Free Full Text:

    “The effect of diet on a single biomarker is insufficient evidence to assess CHD risk. The combination of multiple biomarkers and the use of clinical endpoints could help substantiate the effects on CHD. Furthermore, the effect of particular foods on CHD cannot be predicted solely by their content of total SFAs because individual SFAs may have different cardiovascular effects and major SFA food sources contain other constituents that could influence CHD risk. Research is needed to clarify the role of SFAs compared with specific forms of carbohydrates in CHD risk and to compare specific foods with appropriate alternatives.”

  12. I think its interesting that it’s acceptable for a statin to lower LDL to be considered as a surrogate endpoint. Where has it ever been shown that the positive effects of a statin on heart disease are a result of LDL reduction. In fact

    ‘Munich, Germany – The Z phase of the Aggrastat to Zocor (A to Z) study has shown disappointing results…Treatment with high-dose simvastatin (Zocor®, Merck) failed to show a significant reduction in the primary composite end point of cardiovascular death, MI, readmission for ACS , or stroke. In addition, the high-dose statin regimen was associated with a higher rate of myopathy and rhabdomyolysis.’

    That contradicts the hypothesis because LDL was lowered more with the high dose without benefit!

    It is widely accepted that statins have ‘pleiotropic’ effects, i.e. benefits that have nothing to do with LDL reduction. So it’s nonsense to claim that LDL reduction is an acceptable surrogate endpoint.

  13. It would have helped if you had included a citation originally. The link also refers to regulation to reduce the incidence, so that number may now be out of date.

    From the CDC:

    “Salmonella causes an estimated 1.2 million U.S. illnesses annually, approximately 1 million of which are transmitted by food consumed in the United States (2). Salmonella can contaminate a wide range of foods …”

    So the incidence from eggs is <10%. I wonder what percentage is from non-animal sources. You give me the impression of quoting numbers out of context to advance your agenda.

    Also, the studies about eggs you refer to only established a statistical correlation with eggs, certainly not proof of cause and effect. The studies were controlled for egg consumption and the Harvard Physicians study appears not to have any information about the diets in general. It's a big leap to blame it on eggs.

  14. Well, what are you to make of this “little” meta-analysis (263,932 participants) from the BMJ (1/7/13)?:

    “Higher consumption of eggs (up to one egg per day) is not associated with increased risk of coronary heart disease or stroke. The increased risk of coronary heart disease among diabetic patients and reduced risk of hemorrhagic stroke associated with higher egg consumption in subgroup analyses warrant further studies.”

    “Reduced risk of hemorrhagic stroke associated with higher egg consumption in subgroup”! This is a significant finding and it contradicts many of your videos and posts. You can’t only post articles that reinforce your beliefs, doing so smacks of fanaticism not science. I’m not saying eggs are some panacea food but I am saying this site too often conveniently overlooks other valuable information. If you’re simply touting an ideology because you prefer it, than just be more transparent about it. We all have preferences. But don’t hide your preferences in “science.” That’s deceiving.

    This aside, I do enjoy this site-even if I don’t always agree with its content.

    1. I just read this BMJ study, too, and it contradicts much of what Dr. Greger has established regarding the impact of eggs on heart disease, based on the science he has presented. I would love to see Dr. Greger and other knowledgeable people respond to this huge study. I’m not about to go back to eggs just yet because of the other risks posed by eggs such as increased risk of type 2 diabetes, increased IGF-1 levels, and heterocyclic amines. I look forward to the thoughtful responses of this community.

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