Are Egg Yolks Bad For You? Fact Vs. Myth


Eggs are high in cholesterol, and cholesterol causes heart disease, right? It doesn’t quite work that way.

Before we get into how eggs impact your health, let’s first clarify some common misconceptions about dietary cholesterol (the kind you eat in eggs and other animal products) and blood “cholesterol,” commonly referred to as LDL and HDL.

Much confusion begins with the names, since LDL and HDL are actually proteins (low-density and high-density lipoproteins). This is not the same as the free cholesterol that is present in food. Contrary to what you might expect, eating food cholesterol has a negligible impact on your total blood cholesterol for the majority of the population (though some people are sensitive). Therefore, avoiding cholesterol-concentrated foods like egg yolks for fear of raising your blood cholesterol does not make sense.

But what about the saturated fat? Aren’t eggs still bad for your heart?

Though the official recommendation for the past several decades has been to limit egg (particularly egg yolk) consumption, the vast majority of studies conducted have shown no correlation between eating eggs and heart risk. This held true even when eggs were eaten in relatively large quantities. Some studies have even suggested an overall benefit to eating eggs, yolks and all.

In one large prospective study, people who consumed more than seven eggs per week were not at increased risk of heart-related mortality, and actually had a decreased risk for stroke mortality.

Another study examined the effect of a low-calorie diet of two eggs per day (high-protein, high-cholesterol) versus an equal amount of lean animal protein (high-protein, low-cholesterol) on patients with type 2 diabetes. While both groups showed improvements with LDL, the high-cholesterol egg condition resulted in improved HDL, whereas the low-cholesterol group showed worsened HDL levels.

Eggs may be important for more than just the heart, as well. Since egg yolks are rich in lutein and zeaxanthin, vitamins that are important for eye health, researchers at the University of Massachusetts tested whether consuming two or four egg yolks per day could improve retinal health. They found that more egg yolk consumption may help protect against macular degeneration in those at risk for this age-related eye disease.

To summarize, eating eggs, and particularly the yolks, is not associated with an increased risk of heart disease. In some cases, it may actually be protective of both cardiovascular health and eyes. However, it is important to remember that a small percentage of the population is sensitive to dietary cholesterol, and you should keep in regular contact with your doctor to moderate risk.

When it comes to the science of wellness, distinguishing the facts from the urban legends can be tough. That’s why we’ve enlisted Darya Pino – a scientist, foodie, and self-proclaimed geek girl. Check out the ZocDoc Blog every Tuesday to see her bust the biggest myths in health.

Image: telecommuter breakfast: 4 minute fried eggs, a Creative Commons Attribution (2.0) image from mccun934’s photostream.