Egg consumption and coronary heart disease: an epidemiologic overview

Serum cholesterol has been established as a modifiable risk factor for coronary heart disease. Experimental feeding studies show that saturated fat and cholesterol increase serum cholesterol levels; thus, dietary recommendations for lowering the risk of heart disease proscribe the intake of both substances. Recommendations have also included limits on the intake of eggs because of their high cholesterol content. In free-living populations, diet reflects a pattern of associated choices. Increases in one food may lead to changes in the consumption of other foods that may modulate disease risk. Epidemiologic data are helpful in assessing the importance of foods and nutrients in the context in which they are actually consumed. We review epidemiologic data relating dietary cholesterol and eggs to coronary disease risk. Cholesterol intake was associated with a modest increase in the risk of coronary events. The true magnitude of the association is difficult to estimate because most studies fail to account for potential confounding by other features of the diet. When a full-range of confounding factors was considered, the association between cholesterol intake and heart disease risk was small (6% increase in risk for 200mg/1,000kcal/day difference in cholesterol intake). Several studies have examined egg intake and its relationship with coronary outcomes. All but one failed to consider the role of other potentially confounding dietary factors. When dietary confounders were considered, no association was seen between egg consumption at levels up to 1 + egg per day and the risk of coronary heart disease in non-diabetic men and women.