Are eggs as bad as smoking? N0 – but that didn’t stop a lot of news sources from using that headline.

The headlines stem from a recent article published in Atherosclerosis (a peer reviewed journal -) entitled Egg yolk consumption and carotid plaque, concluding “our findings suggest that regular consumption of egg yolk should be avoided by persons at risk of cardiovascular disease. This hypothesis should be tested in a perspective study with more detailed information about diet, and other possible confounders such as exercise and waist circumference.”

One of the difficulties with modern science is the disconnect between population studies and science (click here). As seen in previous posts, population studies can be an indicator of an issue if the Relative Risk is greater than 3 – depending upon how the study is performed. In this case, patients were asked about diet history – which, as we have pointed out in a number of other studies, is the most flawed way to collect data regarding what is really consumed.

But, aside from the problems with diet history, what happens when we look at their data: They do show that with an increase in eggs per week there was an increase in the plaque as measured in the carotid arteries (the arteries in the neck going to the brain – easy to measure the plaque using a simple hand held ultrasound). The plaque in those arteries also increases with diabetes, which is why they have one of the conclusions about diabetes.

The main issue is the mechanism of action for increasing plaque. Lets just assume for a second that we cannot count out variables such as: how long the patients were on statins, how long they had smoked, if they smoked, how controlled their diabetes was. The old hypothesis was that cholesterol in eggs leads to increase blood cholesterol that deposits itself on arteries. This hypothesis has been disproven about 30 years ago, but still one has to assume that if the cholesterol is the issue – why isn’t total cholesterol correlating with egg consumption?

For a while lipid science focused on the good v bad cholesterol (HDL being good- think Happy for HDL) and LDL being bad (think Lousy for LDL). Do egg yolks increase either the LDL or the HDL? No. We know from science that it is the lipoproteins that cause damage to the arteries, not cholesterol- and raising HDL with niacin or fish oil capsules does nothing for plaque. The latest theory is that the molecules that the lipoproteins carry- tells us about atherosclerosis. The larger molecules being better (the reason that you want larger molecules instead of smaller ones – well, see my son’s train set to explain that – click here).

To this day people continue to profess polyunsaturated and monounsaturated fats as being better than saturated fats. This based on conclusions made from multiple studies, and ignoring other studies. You can see our review of that here.

What about the white? Are there people who just eat egg whites? There are fewer calories in whites (about 10 per cent of the calories found in a whole egg) but could the proteins in the whites be an issue? Finally, even if the positive yolk correlation holds out- are the hens given flax seed or not- as hens fed flax seed have much higher levels of Omega 3 fatty acids, which are healthy for you.
Those who are “old school” will point out- what about breakfast meats- won’t they be an issue (they won’t, but it is a good point). The Paleo-types would ask- “Well, what if they ate their eggs with toast (I mean who doesn’t eat eggs with toast). ”  Paleolithic diet followers believe that grains, and in particular refined grains, lead to atherosclerosis. In the paleo-diet mind they would argue that, “Maybe the evil gluten-filled, non-evolutionary grain, led to a glycemic load that caused profound damage to the arteries.” Paleo types, of course, believe it is grain, not fats that cause the issue.

The other correlation- plaque increased as the people aged. Not surprising- yolks are just along for the ride.  Or perhaps this means that if you eat eggs you will become older. See how silly this all becomes

Conclusion of this is pretty simple: there is no conclusion, there is nothing that backs up that science – and it is a great example in correlation does not equal causation.

REFERENCE:

Egg yolk consumption and carotid plaque J. David Spencea,  David J.A. Jenkinsb, Jean Davignonc Atherosclerosis Volume 224, Issue 2, October 2012, Pages 469–473 PMID: 22882905