Of the many nutritional misconceptions I come across during my consultations, eggs are by far and away the most commonly misjudged food among my health-conscious clients. Many reason that eggs contain cholesterol, cholesterol causes heart disease, and therefore eggs are bad. However, you may be surprised to learn that the scientific evidence for this link is far from clear (Gray & Griffin, 2009), and that current health guidelines suggest an egg a day for healthy people is perfectly acceptable.
I bring this up because I am a big fan of eggs and consider them to be, in moderation, a great addition to a healthy diet. Eggs contain a wide variety of nutrients (USDA, 2009), most notably; eggs are a good source of very high quality protein, about 6g for a medium sized egg, with relatively low total fat content compared to other protein sources such as meat. They are rich in monounsaturated fats (similar to the fats you get in olive oil), and polyunsaturated fats, specifically omega-3 and omega-6. These ‘essential fatty acids’ are important for cell membrane health, nerve function, hormone health and skin health, to name but a few. They are also a source of vitamin D, the sunshine vitamin, which supports immune function and mood and tends to be in short supply in the UK during the winter months. Eggs also provide vitamin B12, which is necessary for a number of metabolic processes including energy production from fat. B12 is predominantly found in meat and fish, so eggs provide an important source for vegetarians.
So what about cholesterol? Well, a medium egg contains around 185g of cholesterol – all within the yolk. However, early studies suggesting a linear correlation between egg consumption and cardiovascular disease appear to have been flawed, and in a review of all the available literature a study in 2009 concluded that the risks had been over stated. Furthermore the authors suggested that up to seven eggs per week was ‘harmonious with a healthful diet’ (Jones, 2009). Even in those with elevated cholesterol, evidence suggests that eggs will not elevate it further, although cutting down may improve matters (Njike, Faridi, Dutta, Gonzalez-Simon, & Katz, 2010). Whilst the link between eggs and cardiovascular disease has been over stated some caution is still advised among certain populations, notably those with diabetes, a disease strongly linked with cardiovascular disease (Djousse & Gaziano, 2008).
So in moderation, eggs can contribute to a healthy diet. They are great at breakfast, versatile, quick to make into tasty meals and relatively cheap compared to other protein sources. So as the science becomes clearer it seems high time eggs lose their cholesterol stigma and are enjoyed by more people with a clear conscience.
Djousse, L., & Gaziano, J. M. (2008). Egg consumption in relation to cardiovascular disease and mortality: the Physicians’ Health Study. Am J Clin Nutr, 87(4), 964-969. doi: 87/4/964 [pii]
Gray, J., & Griffin, B. (2009). Eggs and dietary cholesterol – dispelling the myth. Nutrition Bulletin, 34(1), 66-70. doi: 10.1111/j.1467-3010.2008.01735.x
Jones, P. J. (2009). Dietary cholesterol and the risk of cardiovascular disease in patients: a review of the Harvard Egg Study and other data. Int J Clin Pract Suppl(163), 1-8, 28-36. doi: IJCP2136 [pii] 10.1111/j.1742-1241.2009.02136.x
Njike, V., Faridi, Z., Dutta, S., Gonzalez-Simon, A. L., & Katz, D. L. (2010). Daily egg consumption in hyperlipidemic adults–effects on endothelial function and cardiovascular risk. Nutr J, 9, 28. doi: 1475-2891-9-28 [pii] 10.1186/1475-2891-9-28