Eggs in general and egg yolks in particular have gotten a bad rap for raising cholesterol and increasing the risk for heart attack and stroke. This is not the case and in fact US Dietary Guidelines have been changed as per this quote from the Dietary Guidelines Advisory Committee (DGAC) “cholesterol is not considered a nutrient of concern for overconsumption.”
Not only are eggs and egg yolks not bad for your health the fact is that egg yolks are full of essential nutrients including cholesterol! That’s right you heard it here – cholesterol is an essential nutrient. In fact it is so essential that every human being manufacturers cholesterol in their liver every day. The more cholesterol you take in from food the less you have to make because make no mistake if we eliminated all cholesterol from your body you would soon die! For the vast majority of people intake of cholesterol and saturated fat have little impact on circulating levels of cholesterol and of the “bad” types of cholesterol including LDL. In fact high egg consumption (including the yolk) has been linked to increases in the HDL (good cholesterol).
Egg whites are primarily albumin which is a highly absorbable from of protein, but unlike egg yolks, no one worries about egg whites being unhealthy. Besides cholesterol egg yolks contain several key micronutrients. For example, yolks (but not whites) contain vitamins A, D, E and K along with omega-3 fatty acids. Egg yolks also contain more beneficial folate and vitamin B12. The yolks also contain far more of the nutrient choline than the whites, and all of the antioxidants lutein and zeaxanthin.
So why all the negative press on egg yolks and why do bodybuilder always choose egg whites only? It all started with the research of a guy named Ancel Keys. In his famous “7 Countries Study” Ancel Keys deliberately elected to only base his analysis and conclusions on 7 countries vs the 22 countries he actually looked at. Why? Because this is the only way he could show a link between dietary fat intake and coronary artery disease aka heart disease. Once you add in all 22 countries the supposed link disappears!
This deception is a fact and easy enough for anyone to verify by taking a little time to look at Key’s research and the research refuting his conclusions including long term longitudinal research studies like the Framingham Study which are the gold standard. Even in the case of the Framingham Study people tried to twist the facts. However this quote from William Castelli, the former director of the Framingham Heart study, says it all: "In Framingham, Mass., the more saturated fat one ate, the more cholesterol one ate, the more calories one ate, the lower the person's serum cholesterol. The opposite of what… Keys et al would predict…We found that the people who ate the most cholesterol, ate the most saturated fat, ate the most calories, weighed the least and were the most physically active." It has taken a while but the facts are finally starting to penetrate the American Nutritional Recommendations. Now we are in no way suggesting you deliberatly eat more saturated fat and cholesterol or that eating more will make you more healthy - but clearly cholesterol is not something to be afraid of!
As to body builders not eating egg whites they are focused on maximizing protein and minimizing calories so while yolks are not bad for you they do have more calories and fat than the whites which are mostly protein. However you should keep in mind that a whole egg (yolk and whites) has about 78 calories with the vast majority coming from the yolks. Make no mistake calories DO count, and a little fat goes a long way because fatty foods contain twice the calories of non-fatty foods!
Eggs are a very healthy food choice with high levels of protein and nutrients (if you eat the yolks!), and if you choose free range, organic eggs you are eating a veritable nutrition powerhouse. Another good compromise is to eat say one whole egg and mix in more egg whites to maximize protein without loading up on fat! Like all things it is probably best to eat them in moderation, but egg yolks are not something to be afraid of!