New research shows that egg cholesterol does not impact the harmful, most atherogenic, LDL-cholesterol particles in blood, according to a new study published in the June issue of Metabolism.
Based on this study and others, strategies to effectively control harmful blood lipids that increase risk for cardiovascular disease -- the leading killer of both American men and women -- is to eat a diet that is low in saturated and trans fatty acids, rather than focusing on dietary cholesterol.
University of Connecticut researchers studied over 50 men and women and found that the addition of either one egg or three eggs a day did not raise the fractions of LDL-cholesterol that increase one's risk for heart disease. "We found that the dietary cholesterol in eggs does raise the LDL-1 and LDL-2 fractions but it does not impact the small, dense LDL-3 through LDL-7 particles that are the greatest threat for cardiovascular disease risk," explained Maria Luz Fernandez, PhD. "We also found that that egg cholesterol did not impact the small, dense LDL particles among a sub-set of participants who were genetically predisposed to being most sensitive to dietary cholesterol."
Only in the past decade have researchers found that LDL-cholesterol has many fractions, with varying degrees of risk for cardiovascular disease. Prior to this groundbreaking discovery, scientists did not understand LDL- fractions and only used total LDL-cholesterol measures as risk for heart disease. Any increase in LDL cholesterol would have been thought to result in an increase in risk, but this has been refuted in more recent studies. This is one possible explanation why studies have not consistently shown a positive association between LDL-cholesterol and heart disease, explains Fernandez. "The way we are now giving dietary advice to manage blood lipid levels is changing, due to the more sophisticated measures of LDL that we have available."
Research shows that LDL-1 and LDL-2 are large particles that pose little risk while fraction LDL-3 through LDL-7 are small, dense particles that wreak havoc on the arteries by triggering inflammation and increasing oxidation. The researchers did find that the harmful LDL fractions were influenced by gender, with men having a greater concentration of small LDL particles compared to women, regardless of the type of diets they followed.