Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
15 Aug

Are Eggs Really as Bad for Your Arteries as Cigarettes?

This past weekend, amidst all the Ancestral Health Symposium madness, I caught the headline while flicking through my phone for a few brief seconds. Didn’t open it up, though. Just cruised on past. I’d hoped to just forget about it, to ignore it, to banish it to the back of my mind where half truths and junk studies go to die. And truth be told, I pretty much had forgotten about it until I checked my email to find a ton of frantic emails from readers wondering if their beloved and dependable egg yolk breakfasts were killing them faster than the cigarettes they don’t smoke. What? You didn’t hear?


Followed by (with less hysterical capitalization) “May increase carotid plaque build-up.”

So what are we looking at here?

We’re looking at a study in which a trio of researchers (two of whom with extensive ties to the statin industry) quizzed a group of middle-aged and elderly stroke patients about their lifelong egg intake and smoking history, making sure to stress the importance of accuracy and honesty in their answers. Yes, you heard me right: they expected people to remember every last egg they ever ate. Still, everyone in the study was assumed to have supernatural memory, so I guess it evens out.

Those who ate the most eggs were the oldest – almost 70 years old on average, compared to the relatively sprightly 55 year-old egg avoiders. It’s pretty well accepted that with age comes the progression of atherosclerosis, a process that takes, well, time to occur. Plaque doesn’t just snap into existence; it develops. All else being equal, the older you get, the more plaque you’ll have.

Those who ate the most eggs also smoked the most and were the most diabetic. To their credit, the authors tried to control for those factors, plus several others. Although they tried to control for sex, blood lipids, blood pressure, smoking, body weight index, and presence of diabetes, the study’s authors didn’t – couldn’t – account for all potentially confounding variables. In their own words, “more research should be done to take in possible confounders such as exercise and waist circumference.” Hmm. “Possible” confounders, eh?

Exercise reduces inflammatory markers of atherosclerosis.

Exercise even reduces markers of atherosclerosis in pre-pubertal obese children!

Exercise reduces thickness of the carotid arterial wall. It doesn’t get much clearer than that. Exercise is a massively confounding variable that the authors failed to take into account.

What about waist circumference?

A high waist circumference predicts atherosclerosis of the carotid artery.

Or how about stress, which also wasn’t considered?

Perceived daily psychological demands – the amount of crap you perceive to be heaped on your plate – are associated with progression of carotid arterial plaque.

Yeah, it’s not like the size of a person’s waist, whether or not they move of their own volition or sit in an easy chair all day, and how much stress they endure have any impact on their risk of developing atherosclerosis. Those things may be linked, and I’m sure the authors would have loved to include them in their analysis, but there just wasn’t enough space on the questionnaire. Besides, it’s not like a little physical activity and mediation could even undo the damage wrought by 4.68 sinful egg yolks per week. Why, that’s nearly a half dozen!

Seriously, though, the subjects were all stroke patients who’d lived to tell the tale. They’d been in contact with the medical community (you generally don’t just shake off a stroke without medical attention), who no doubt gave them the standard required advice to prevent another event, which includes “a reduction in saturated fat and cholesterol intake…and a boost in physical activity.” Since the egg-eaters obviously didn’t listen to their doctors’ recommendations to cut back on cholesterol intake, I’d wager they treated the exercise recommendations with similar levels of disdain. What do you think?

Here’s what I think: this is an observational study whose already limited worth depends entirely on the memory of an inherently fallible creature being infallible. As such, it cannot assign causality, contrary to what the media (“Egg Yolks Can Quicken Hardening of the Arteries“) and authors (“It has been known for a long time that a high cholesterol intake increases the risk of cardiovascular events”) say. Furthermore, why single out egg yolks? I mean, I get it – the authors sort of have a vendetta against eggs – but what about other foods? Were those even analyzed or asked about? What about the stuff that people generally eat with eggs, like pancakes and vegetable oils, or the foods that contain egg yolks, like baked goods and mayonnaise? For all we know, egg yolk intake could have been a marker for eating garbage; most people aren’t tossing raw yolks into post-workout shakes, gently poaching eggs with coconut vinegar, or horrifying co-workers with a bag full of hard-boiled eggs like we Primals are wont to do. They’re getting Grand Slams at Denny’s, eating bologna sandwiches with mayo on white bread, and overcooking scrambled eggs in canola oil until they’re rubber.

For fun, though, let’s look at what some other studies have found with regards to the artery-clogging capabilities of whole eggs:

Egg consumption and endothelial function: a randomized controlled crossover trial. Two eggs daily did not impair endothelial function (the flow of blood through the arteries), nor did it increase total or LDL cholesterol. Overall, eating two eggs a day elicited no change in cardiovascular health when compared to eating oatmeal (a cardiologist’s pride and joy).

Daily egg consumption in hyperlipidemic adults – effects on endothelial function and cardiovascular risk. In patients with high cholesterol, eating several hard-boiled eggs a day had no effect on endothelial function.

Effect of a high-saturated fat and no-starch diet on serum lipid subfractions in patients with documented atherosclerotic cardiovascular disease. Obese patients with heart disease ate lots of saturated fat, zero starch (including zero grains – sound familiar?), and tons of vegetables, and saw massive weight loss without any negative effects on their blood lipids. Once upon a time, I had access to the full study (it was freely available at the website for the Mayo Clinic, who’s since taken it down…wonder why), and I remember seeing that they ate three or four eggs a day. If egg yolks were bad for all heart disease patients, these guys would have felt the effects.

Okay, despite all those confounders and other egg studies that support yolks as harmless and the fact that this was merely an observational study without the power to assign causation and whose authors failed to even propose a potential mechanism of action, let’s entertain the notion that something was going on with this population of egg eaters. What if the egg yolks did have something to do with the atherosclerosis?

In a previous post on “Human Interference Factor,” I highlighted a study showing hens given an unnatural industry-standard diet high in omega-6 containing grains (soy and corn) produce less healthful eggs than hens on a more natural diet of grains lower in omega-6 with supplementary antioxidants. When subjects ate two of the soy/corn-fed eggs a day, which were high in omega-6 fats, their oxidized LDL levels were increased by 40%. Subjects who ate two of the other eggs each day, which were low in omega-6 fats, had normal levels of oxidized LDL (comparable to subjects in the control group, who consumed between two and four eggs a week). Since the oxidation of LDL particles is strongly hypothesized to be a crucial causative factor in atherosclerosis, it’s conceivable that eating normal, industrial eggs could have a negative effect on carotid plaque.

Anyway, what are the takeaways here?

Exercise, practice stress reduction, and get your waist circumference checked.

Don’t smoke.

Don’t age.

Don’t pay too much attention to ridiculous observational studies (this is part of stress reduction).

Oh, yeah – eat egg yolks, and lots of them. Doubly so if you’re low-carb (remember the starch/grain-free high-egg diet referenced above). Make ’em pastured, if possible, or at least from hens that ate something besides soy and corn. They’re more nutritious and probably “safer” than industrial eggs.

(In retrospect, that mention of the authors’ ties to the pharmaceutical industry was a low blow. After all, I myself am a direct benefactor of my local pastured egg industry; they pay me in delicious golden yolks.)

I hope you found this post helpful. Have at it in the comments.

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. Thank you for posting this Mark. I saw this study posted and all I wanted to do to respond is channel your brain. Now I can. Copy/paste link. Thank you!

    Ryan wrote on August 16th, 2012
  2. “Don’t pay too much attention to ridiculous observational studies (this is part of stress reduction).”

    That got a chuckle outa me. =)

    Joedetroit wrote on August 17th, 2012
  3. I was an avid egg eater until I got tested for food sensitivities, of which egg whites were just one of many things I have to stay away from. I haven’t had eggs since Jan. 29,2012. I am a lab tech so checked my cholestrol levels 3 months later. All my levels where normal. I have always had elevated chol and LDL levels. My doctor said to keep doing whatever I have been doing, as she was very happy to see my levels. Just saying……

    tori wrote on August 17th, 2012
  4. egg yolks: make them pasteurized??? Not sure I like that recommendation. Any explanation? I’ve been working for years to get my MD husband to eat eggs/yolks (strong family history of heart disease) without clutching his chest (coconut oil, too). Even *he* laughed at this study.

    Pam wrote on August 17th, 2012
  5. The poor old egg getting a bad rap again. Eat eggs, don’t eat eggs, eat eggs – for god sakes make up your minds! It seems like a perfect package to me, after all it sustains life (the yolk that is). I’ll keep eating them.

    mamab wrote on August 17th, 2012
  6. As a healthy 75 year old….eat everything but in moderation. Simple, huh.

    Arnold Orgolini wrote on August 17th, 2012
  7. Good article. I missed the correlation between eggs and age in my criticism.

    Erin Kaplan wrote on August 17th, 2012
  8. I was unable to read through this very lengthy chain – but to add my own suggestion – eat your eggs raw. I have 4 raw eggs every day. There is nothing better for you. For those worries about pathogens, keep in mind that every shopping mall in America used to have an “Orange Julius” which would sell an orange frothy shake made of orange juice, sugar and a raw egg. And millions of these drinks were consumed each and every day. Just make sure that your eggs are of the highest quality – non-soy fed if possible.

    Eric wrote on August 17th, 2012
  9. Hmmm…
    From the footnotes section of the study:

    “CONFLICT OF INTEREST: None of the authors receives funding from purveyors of margarine or eggs. Dr Spence and Dr Davignon have received honoraria and speaker’s fees from several pharmaceutical companies manufacturing lipid-lowering drugs, and Dr Davignon has received support from Pfizer Canada for an annual atherosclerosis symposium; his research has been funded in part by Pfizer Canada, AstraZeneca Canada Inc and Merck Frosst Canada Ltd.”

    Susan wrote on August 17th, 2012
  10. I heard about this study on Wait Wait Don’t Tell Me on PBS and guessed it was bogus. Whenever I hear about this kind of stuff I think, “Uh huh, but what else were they eating.”

    To put the blame for a health problem on one thing is ridiculous.

    And if eating egg yolks has the same effect as smoking cigs then how is it I can sprint and do high intensity exercise without falling over and gasping for air?

    Richard Bienvenu wrote on August 18th, 2012
  11. There is more research that points to health hazards associated with egg (hen) consumption called the Harvard Nurse’s Study.
    This study was started in 1976 and was conducted over 30 years involving over 100,000 women, many of whom have now died. It is a study of risk factors for death. The number one killer of women is cardiovascular disease. Comparing risks, they came to the conclusion that consuming one egg a day had the equivalent risk of consuming 5 cigarettes daily for 15 years.

    You can see more information regarding this study at, Google, or YouTube by entering “What women should eat to live longer”

    It does not matter if the eggs are free range, organic, from Safeway, or produced in a lab.
    All eggs have an enormous amount of cholestrol that was meant to sustain an embryo for a long time.
    They were not meant to be consumed by humans on a regular basis

    Bill Morten wrote on August 18th, 2012
    • bwhahaha, ok dude.

      That same study is where they got the headlines “HRT will save women’s lives” 10 yrs later when actual studies were done they found out HRT caused heart attacks.

      Mark wrote on August 23rd, 2012
  12. It amazes me the way that people respond to information like this. It is the same reason that cigarette smoking killed so many people in the years priors to the late 1960’s.

    Smoking, like food habits are hard to change. I guess that people’s will will have to be broken down by disease and / or deaths in one’s family.

    Bill Morten wrote on August 18th, 2012
  13. Thanks, Mark, for changing your mind and tackling this egg yolk panic inducing media blurb.

    I looked up some sources and foun an enormous list of international names with no background data attached. I know Europeans don’t use the MD after their names, but I am wondering if this was a list of miscellaneous people, all with a vested interest in pharmaceutical companies.

    All I did about it was to comment: “check out Paleo/Primal scientists’ findigs.”

    Hope they did. Hope they checked out YOURAS!

    Susan Holland wrote on August 18th, 2012
  14. I actually just did an interview with Tom Naughton of Fathead fame for my blog and near the end he brought up this very point. “Don’t pay attention to the sensational headlines because they’re based on bad science.” I’m paraphrasing.

    But he’s right. These “scientists” do a very limited observational study and consider it gold.

    JB Primal wrote on August 18th, 2012
  15. Today was my last day at work before I head to college. One of my customers asked me what I was majoring in, and so I told her, Dietetics and Exercise Science. Upon hearing that I was interested in nutrition her eyes popped out of her head and she said “Did you hear that egg yolks are as bad for you as cigarrettes?!” I simply rolled my eyes and said, “Yes, that’s a bunch of bull. I’m still eating eggs.” :) On top of that, a few months back, my dad was diagnosed with high blood pressure. the doctors wanted to put him on high blood pressure medicine but he refused. After that doctors appointment, I introduced him to low carb primal eating and helped him with an exercise plan and he lost about 30 pounds. That being said, he eats eggs and bacon every morning for breakfast. Today was a follow up appointment to see if his blood pressure got better. Needless to say it did. Guess cigs aren’t that bad for us after all? lolol. CW makes me so mad.

    Sarah wrote on August 18th, 2012

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