Eggs are a nutrition packed, low fat source of protein. They contain a variety of vitamins and antioxidants and most of the fat is made of the ideal healthy fat. The egg also manages to have all these benefits with low calories. However, the egg also has cholesterol, a substance often associated with heart disease or stroke because of its artery clogging abilities. Because of this cholesterol, there have been cautionary recommendation to limit eggs to a few servings per week.
Researchers from China and Boston assessed previous studies to see if increased egg consumption was associated with an increase in the risk of heart disease or stroke. The review, published in the British Medical Journal, found that eating up to 1 egg per day did not increase risk of heart disease or stroke.
The systematic review included eight cohort studies which asked participants about egg consumption and followed them for the development of heart disease or stroke. Egg consumption information was gathered through a series of questionnaires but most did not include cooking method or size of eggs. Incidence of coronary heart disease was tracked in 263,938 participants and incidence of stroke was tracked in 210,404 participants.
Patients were followed for up to 22 years. During that time there were 5,847 incidents of coronary heart disease and 7,579 strokes. Compared to participants with the lowest egg consumption, those that had up to 1 egg per day did not have an increased risk of heart disease or stroke. However, an evaluation of a smaller group of participants with diabetes showed an increased risk of coronary heart disease with higher egg consumption.
Systematic reviews are generally considered a reliable method of research because it pools large amount of data. The more data is involved the more reliable the outcomes will be. However, the systematic review is only as reliable as the studies that make it up. In this case, the review was made of cohort studies. These studies simply observe a pool of participants without controlling the treatments or other factors that may affect outcomes. They are useful in seeing potential connections but cannot determine cause and effect. The study also heavily relied on participants accurately filling out food questionnaires or not having any major changes in eating habits over the course of the study.
Eggs are a good source of protein without the high amount of saturated fats and calories associated with other high protein food like red meat. They are also versatile enough to easily become part of any meal in the day. Add it to your breakfast for a filling meal to start your day, try it in a salad to boost its nutrition value, or use it to replace less healthy protein options. Keep in mind that although eggs have many good properties and this study showed no heart disease or stroke risks, it should only be part of a balanced diet not a major cornerstone. Your diet choices should also be based on your overall health. Talk to you doctor about dietary changes if you have risks of heart disease or stroke, like high cholesterol or diabetes.
American Heart Association
National Heart, Lung, and Blood Institute
Rong Y, Chen L, Shu T, et al. Egg consumption and risk of coronary heart disease and stroke: dose-response meta-analysis of prospective cohort studies.BMJ. 2013;346:e8539.
Last reviewed February 2013 by Brian Randall, MD