Nutritional Claim: "Egg yolks contain significant amounts of cholesterol and pose problems to your health."
How many times have you heard the phrase, “egg yolks are bad for your health, the cholesterol clogs up your arteries”? Let’s use another cliché, if I had a penny for every time I heard eggs were bad for my health, I certainly wouldn’t need to be writing this post. This common belief that egg yolks are bad for health has led to the widespread practice of removing the yolks from eggs prior to cooking, but is this justified?
Before we get into the cholesterol debate, let’s take a look at the nutrient content of an egg yolk vs. white. An egg yolk contains nearly half of an eggs protein content (43%), over 90% of an eggs iron, calcium, and many B vitamins, and 100% of an eggs fat soluble vitamins (A, D, E, K) and essential fatty acids. Egg whites on the other hand, contain far fewer nutrients, 57% of an eggs protein, 80% magnesium and 87% of sodium.
The average egg contains between 180 to 215mg of cholesterol, and there is no denying for a single food source this a large amount of cholesterol. However, many of the early studies, linking low-density lipoproteins (LDL; ‘bad cholesterol’) to the risk of heart disease were confounded by foods high in saturated fatty acids. We now know that, although elevated LDL levels do increase the risk of heart disease, saturated fatty acids influence blood cholesterol levels (low-density lipoproteins) to a much greater extent than dietary cholesterol. And it is incorrect to think that the cholesterol we eat converts directly into blood cholesterol. The total fat and saturated fatty acid content of eggs is not high, and the fat in eggs is predominantly unsaturated (44% monounsaturated; 11% polyunsaturated). Even if the dietary cholesterol in eggs does marginally increased blood cholesterol levels, there is no evidence that this has a direct association with an increased risk in heart disease. Additionally, some studies have demonstrated that consuming eggs increases high-density lipoproteins (HDL; ‘good cholesterol’) levels, partially offsetting the effects of egg consumption on LDL levels.
Conclusion: Nutritional Fallacy. The egg yolk is extremely nutrient dense, and recommendations to avoid its consumption are unfounded. Removing the yolk will result in you missing out many important nutrients, such as iron, healthy fats, calcium, B vitamins, and a large portion of an eggs protein content. Consuming eggs within moderation (2-3 eggs per day) poses very little, if no threat, to your health.
About the Author
Mark Funnell holds a BSc (Honours) degree in Sport and Exercise Science and an MSc in Sport and Exercise Nutrition from Loughborough University. He is currently working as a Performance Nutritionist for the England and Wales Cricket Board with both the England Women’s Academy and Midlands Regional Disability Cricket squads. Additionally, Mark is a graduate member of the Sport and Exercise Nutrition Register (SENr), an ISAK Level 1 Anthropometrist and a UK Anti-Doping advisor.