Cardiovascular disease kills more Americans than any other cause. Many people associate the LDL fraction of cholesterol with increased risk of cardiovascular disease. Eggs contain lots of cholesterol. Thus, some experts recommend avoiding eggs, at least the yolks, where cholesterol is located. On the other hand, a 2005 study showed that feeding people two eggs per day for six weeks didn't increase total or LDL cholesterol, Also,blood flow in the brachial artery (in the arm) didn’t differ significantly between the two-egg eaters and oat eaters.
The tide appears to be turning with respect to eggs. The Dietary Guidelines for Americans 2010 from the US Departments of Agriculture and Health & Human Services concluded that the available evidence showed that eating one egg per day is not harmful and does not adversely affect serum cholesterol or triglycerides. Egg consumption favors production of HDL cholesterol and large LDL cholesterol particles that may confer a measure of protection against atherosclerosis. Small LDL particles are more readily oxidized than large LDL particles and can more easily penetrate artery walls, leading to atherosclerosis. Furthermore, eggs provide many nutrients, including high-quality protein, carotenoids, essential fatty acids, plus many vitamins (A E, D, K, B-vitamins) and minerals (K, Ca, Fe, P, Zn, Cu, Mn, Se) at relatively low cost. Thus, it seems that eating eggs on a regular basis promotes good health (Kanter et al. 2012).
Two groups of researchers in 2013 reviewed the scientific and medical literature for studies that related egg consumption to cardiovascular disease risk. For one group, eight studies passed the screening process. These studies showed that people who consumed an average of one egg per day didn't have increased risk of cardiovascular disease. In fact, consumption of one egg per day was associated with a slightly lower risk of hemorrhagic stroke (Rong et al. 2013). The researchers also found that persons who ate one egg per day and who were diabetic had a slightly higher risk of cardiovascular disease. Thus, diabetics probably don't want to eat an egg every day.
The other group of researchers conducted a meta-analysis of 16 longitudinal studies. Data from the 16 studies were pooled to create greater statistical power to detect associations between egg consumption and risk of cardiovascular disease, cardiac mortality, and diabetes. These researchers didn't find a significant association between egg consumption and cardiovascular disease, cardiac mortality. The researchers did find an increased risk of developing diabetes. Furthermore, subjects with diabetes at baseline has significantly elevated risks for cardiovascular disease (Shin et al. 2013).
I believe that demonizing eggs isn’t justified, at least for non-diabetic people. I eat a two-egg omelet pretty much every day, although I’m not necessarily suggesting that you do the same. But eggs are a cheap source of high-quality protein. Eating one egg per day seems like a sensible thing to do, especially for people with limited financial means.
Mitchell M. Kanter, Penny M. Kris-Etherton, Maria Luz Fernandez, Kasey C. Vickers, and David L. Katz. 2012. Exploring the Factors That Affect Blood Cholesterol and Heart Disease Risk: Is Dietary Cholesterol as Bad for You as History Leads Us to Believe? Advances in Nutrition 3: 711–717.
Ying Rong, Li Chen, Tingting Zhu, Yadong Song, Miao Yu, Zhilei Shan, Amanda Sands, Frank B Hu, and Liegang Liu. 2013. Egg consumption and risk of coronary heart disease and stroke: dose-response meta-analysis of prospective cohort studies. BMJ 346: 346:e8539.
Jang Yel Shin, Pengcheng Xun, Yasuyuki Nakamura, and Ka He. 2013. Egg consumption in relation to risk of cardiovascular disease and diabetes: a systematic review and meta-analysis. American Journal of Clinical Nutrition 98:146–59.