Much has been written about eggs that has cast doubt on their nutritional value. As a result, most people are not aware of what is true and what is not. Misconceptions abound: are they healthy? How many daily servings are recommended? Who should avoid eating them? And probably the most common: will eating them increase my blood cholesterol levels?
While it is proven that eggs do contain a significant amount of dietary cholesterol, there also still remains a plethora of misinformation regarding eggs' true nutritional value, which has prevented many from enjoying them as part of a healthy diet.
Is there a limit to how many eggs I can eat a week?
Health Canada does not have a specific daily limit on dietary cholesterol. It recommends that you consume as little as possible while still maintaining your daily nutritional intake. Considering that one egg yolk contains around 215 mg of cholesterol, a two-egg omelette would contribute a significant amount of cholesterol to your day's consumption. But before you do away with omelettes, soufflés, and the like, consider that only a small amount of cholesterol in food will actually work its way into the bloodstream.
Studies show that saturated and trans fats are the real culprits behind elevated levels of blood LDL (bad) cholesterol. In fact, the Heart and Stroke Foundation of Canada stresses the importance of limiting foods containing trans and saturated fats, over limiting dietary cholesterol, since foods containing trans and saturated fat raises your blood cholesterol the most. Worth noting, eggs contain little saturated fats and no trans fats, and the cholesterol that comes from eggs is from the egg yolk; egg whites have no cholesterol.
What is the link between eggs and heart disease?
While it is true that elevated LDL blood cholesterol levels do cause the hardening of arteries, a factor associated with coronary heart disease (CHD), studies have consistently shown that there is no definite linkage between egg intake and CHD in healthy people. One study from 1999 looked at the egg consumption of 117,000 nurses and health professionals over a 14-year period and found that eating up to one egg a day did not increase the risk for CHD.
A study published in the American Journal of Clinical Nutrition in 2008 followed 21,327 male physicians over a 20-year period and found that consuming up to 6 eggs a week was not linked with a greater risk of developing cardiovascular disease.
It is important to note that the same research does draw a link between egg consumption and cardiovascular disease risk for men who have diabetes. Those who ate 7 or more eggs a week had double the risk for death (most likely from heart disease) than those who consumed less than one egg a week.
What are the nutritional values of eggs?
Eggs are a good source of 11 nutrients that include folate, riboflavin, selenium, vitamin B12, and vitamin A. Eggs are also an excellent source of choline, a nutrient that is necessary for nerve and brain development. Women who are pregnant or breast-feeding require increased intake of choline.
Eggs are one of the few whole foods that contain vitamin D, a nutrient that is important in maintaining optimal bone health. Eggs are also rich in lutein, an antioxidant that can protect against the development of age-related macular degeneration or cataracts.
Additionally, studies have shown that lutein intake may actually reduce the risk for CHD by minimizing the formation of plaque on the artery walls. Moreover, research has demonstrated that eggs enriched with omega-3 from fish oil helps lower triglyceride levels - fats found in the bloodstream that is linked to CHD.
Eggs are also an excellent source of high-quality protein. They contain all the essential amino acids needed by the body to build valuable proteins. Eggs also provide a greater amount of the branched chain amino acids (BCAA), the amino acids that regulate muscle growth and control the release of insulin. Leucine, a BCAA, was found to help to reduce loss of muscle tissue, promote loss of body fat, and stabilize blood glucose levels. Researchers explain that eating high-quality protein, especially at breakfast, seems to be the key to long-term weight loss and maintenance.
When looked at as a whole food and not merely as a source of dietary cholesterol, the positive benefits associated with eggs being a part of a healthy diet are overwhelming. As research attributing egg consumption to CHD is lacking, one whole egg a day seems safe and beneficial.
If you have diabetes, talk to your doctor or dietitian about your concerns of eating eggs. If you are still worried about the amount of dietary cholesterol in eggs or the role it may play in increasing levels of blood cholesterol, consider enjoying your eggs without the yolk.
Brennan Robertson, Hon. B.Sc. (Nutrition)
With updates by the MediResource clinical team