Wednesday, August 15, 2012

Eating Egg Yolks Increases Arterial Plaque, Rivals Smoking

Dr. J. David Spence, professor of neurology at the University of Western Ontario, has returned to the topic of eggs. He and his colleagues had me Rethinking Eggs back in 2010. In his latest study...

Egg Yolk Consumption And Carotid Plaque, Atherosclerosis, August 2012

Here's a press release on the study:
Research Finds Egg Yolks Almost As Bad As Smoking

... Spence and his team looked at total plaque area in 1262 patients attending a vascular prevention clinic.
"Spence found regular consumption of egg yolks is about two-thirds as bad as smoking when it comes to increased build-up of carotid plaque, a risk factor for stroke and heart attack."
So, both smoking and eating eggs was associated with increased plaque. Smoking was worse, but eating three or more eggs a week came close.

People with diabetes who eat eggs have an even greater risk for heart attack than people without diabetes:
"In diabetics, an egg a day increases coronary risk by two to five-fold," said Spence.
In his paper from 2010, Spence said the problem with dietary cholesterol* was three-fold. It:
  1. Increases the susceptibility of LDL to oxidation "by 37% in one study and by 39% in another." (Oxidized LDL contributes to the formation of plaque.)
  2. Increases postprandial lipemia. (Increases triglycerides and other lipid particles after a meal.)
  3. Potentiates the adverse effects of dietary saturated fat. (This is called the "bacon and egg effect" or the "egg and cheese effect." At high cholesterol intake, a high saturated fat diet leads to higher LDL than if you paired the same saturated fat diet to a lower cholesterol intake.)
* Egg yolks are high in cholesterol. Says Spence: "The yolk of a large egg provides more than the 210 mg. of cholesterol in a Hardee's Monster Thickburger, which contains two-thirds of a pound of beef, three slices of cheese and four strips of bacon."

Related: Small Amounts of Dietary Cholesterol Cause Arterial Lesions


Reijo Laatikainen said...

In a Harvard prospective cohort eggs as protein source were not linked to cardiovascular disease whereas red and processed meat were. This particular study by Spence et al. was a cross sectional, ie. weak in showing any causality.

Larger and better designed Harvard study

Anyway, food for thought.

Bix said...

Some differences:

- The Harvard study was in women only, who enjoy the protective benefit of their hormones, prior to menopause at least. The present study was in men and women.

- Women in the Harvard study were healthy, "no known cancer, diabetes mellitus, angina, myocardial infarction, stroke, or other cardiovascular disease." Participants in this study were "patients attending vascular prevention clinics."

- The population in this study was older than that of the Harvard study, a mean age of 61.5 years.

I don't think it's wise to generalize the findings from a younger, healthier, all-female population to an older, less-healthful population of mixed-gender. Eggs yolks may indeed worsen their arterial health.

Bix said...

Reading through the comments here:

Is eating egg yolks as bad as smoking?, CNN


Bix said...

There seems to be a lot of anger about this study. It isn't even a windfall, just a drop in the sea of knowledge. But the comments I've seen ... many are acerbic. I don't understand the emotion.

I was just on a site called Mark's Daily Apple. It doesn't look like the author, Mark Sisson, has formal medical training. Nonetheless, he is dispensing medical advice. As regards this study, he says everyone should eat eggs, "Oh, yeah – eat egg yolks, and lots of them. Doubly so if you’re low-carb."

So, people who have colon cancer, diabetes, hypertension, protein in their urine and kidney disease. People who have had a stroke or heart attack. These are the type of people in this study. He is advising them to eat several egg yolks a day.

RB said...

I avoid eggs because of their high cholesterol. But many people including Dr. Oz extol the health benefits of eggs. Dr. Oz recently tweeted.
"If anti-aging is a priority, these are the foods that should be in your shopping cart. "

Eggs were in the list. Here is what it said about eggs.

"Your favorite breakfast food just got a little bit better! Eggs are rich in iron and biotin, which help keep your skin and hair healthy and full."

There may be healthful nutrients in eggs, but I think its harmful cholesterol outweighs any benefits. I don't understand why some health professionals recommend eggs in one's diet

virginia said...
This comment has been removed by the author.
virginia said...

I noticed a big drop in my LDL (and total cholest.) when I eliminated egg yolks from my diet. I couldn't get my numbers to budge, didn't want to increase Lipitor to 20mg, so as a last resort, I eliminated my 3X/week "runny" egg. I'm where I should be now. (Probably saved myself from a salmonella infection, too)

Bix said...

Dr. Oz recommends eggs? How about that.

When I was in school, eggs were a no-no, the yolks at least, for their cholesterol. Later, the American Egg Board came out with their successfully marketed campaign, "The Incredible, Edible Egg." I believed their claim that "There's no reason you can't enjoy them for breakfast every day."

A couple years ago I read criticisms of their studies. They based their claims on effects on healthy people, and didn't follow them long enough, a time when ill effects would show up.

I also read a lot of literature showing eggs were risky for people with diabetes. Even the Egg Board cited this.

Bix said...

Interesting, virginia. What do you eat instead?

I've been on sites where people say high cholesterol is good for you. I don't know about all these markers. But plaque can't be good.

Claudia said...

The anger is because people want to eat their eggs. That and the internet brings out the worst in people.

virginia said...

I only eat the egg whites, and it's usually a veggie frittata of some sort. Filling. I truly went through withdrawal, but the drop was significant.

Bix said...

So, you still eat eggs. I thought maybe you went for oatmeal. I'm curious what people get together for breakfast when they're working against the clock. I usually grab day-old sweet potatoes. (Not that I don't love them.) Or peanut butter on some fanatic flourless bread.

Anonymous said...

Egg yolks are bad for you if they are cooked and beaten with egg whites, fried in oil, and eaten with fatty bacon. Eaten by itself in its raw original form (without egg whites) is best.