What the Numbers Reveal
Studies have looked at the effect of egg consumption on blood cholesterol levels and have found a small impact. This is important because newer research has identified the LDL:HDL ratio ("good" cholesterol to "bad" cholesterol) and the Total:HDL ratio (the sum of all cholesterol components to "good" cholesterol) to be better indicators of heart disease risk than either indicator alone.
A review of more than 30 studies published in the Journal of the American College of Nutrition in 2008 argues that the LDL:HDL ratio is a much better indicator of heart disease risk than either indicator alone because the ratio reflects the "two-way traffic" of cholesterol entering and leaving the blood system. (1)
The Journal of Nutrition published a study in 2008 that found that overweight men who ate eggs while on a carbohydrate-restricted diet have a significant increase in their HDL levels (the "good" cholesterol) compared to men who did not eat eggs. (2)
A 2008 study from the journal Ateriosclerosis, Thrombosis, Vascular Biology found low HDL is associated with poor memory and a decline in memory in middle-aged adults. (3)
A 2008 study published in the American Journal of Clinical Nutrition concluded that a diet rich in choline and betaine is associated with lower concentrations of homocysteine, a marker of inflammation. High levels of homocysteine or inflammation have been associated with cardiovascular disease, Alzheimer's and dementia. (4)
In 2005 researchers at the University of Connecticut found that healthy, elderly adults who ate three eggs a day for one month did not experience an increase to their LDL:HDL ratio or to their Total:HDL ratio, which are two major indicators for heart disease risk. (5)
Fernandez ML and Webb D. The LDL to HDL Cholesterol Ratio as a Valuable Tool to Evaluate Coronary Heart Disease Risk. JACN (in press).
Mutungi G, et al. Dietary cholesterol from eggs increases plasma HDL cholesterol in overweight men consuming a carbohydrate restricted diet. J Nutr. 2008;138:272-276.
Sing-Manoux, et al. Low HDL Is a Risk Factor for Deficit and Decline in Memory in Midlife. The Whitehall II Study. Arterioscler, Thromb, Vasc, Biol. 2008; 28:1557-1563.
Detopoulou, Paraskevi et al. Dietary choline and betaine intakes in relation to concentrations of inflammatory markers in healthy adults: the ATTICA study. AJCN 2008; 87:424-430.
Greene CM, et al. Maintenance of the LDL cholesterol: HDL cholesterol ratio in an elderly population given a dietary cholesterol challenge. J Nutr. 2005; 135:2799-2804.