The study, supported by the American Egg Board, measured the influence of a high-cholesterol diet, based on daily egg consumption, on the atherogenicity, or potential to lead to heart disease, of low-density lipoprotein (LDL) particles.
Researchers have recently found that LDL cholesterol has many fractions, with varying degrees of risk for cardiovascular disease. Prior to this, total LDL-cholesterol was measured to gauge 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 from the University of Connecticut.
"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," she added.
Egg producers in the US and UK have been given a boost in recent months by consumers following the protein-rich Atkins diet. The British egg industry saw its first sustained sales rise in many years last year, with eggs up 4 per cent in the first seven months of 2003, helped by consumer education campaigns to try to dispel myths that consumers should not eat more than three eggs per week.
However elsewhere egg producers have been slow to market the health properties of eggs and egg proteins, with many citing the food's 'bad reputation' as a barrier to growth.
Writing in the June issue of Metabolism (vol 5, issue 6, pp 823-830), the Connecticut team said they randomly assigned 27 premenopausal women and 25 men to either an egg (resulting in 640 mg of additional dietary cholesterol) or a placebo diet for 30 days, followed by a three-week washout period.
The larger LDL-1 subclass was greater in hyperresponders, those more sensitive to dietary cholesterol, following egg intake, showing that the consumption of a high-cholesterol diet does not negatively influence the atherogenicity of the LDL particle, reported the scientists.
The American Egg Board said the study, alongside others, shows that strategies to control blood lipids that increase risk for cardiovascular disease, the world's biggest killer, should focus on a diet low in saturated and trans fatty acids, rather than on dietary cholesterol.
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.