What do egg yolks and cigarettes have in common?


Too much of either one may clog your arteries.

That’s according to a study published on line Monday in the journal Atherosclerosis, which examined the effects of egg-yolk consumption on the thickening of arterial walls.

Researchers led by David Spence of Western University in Ontario, Canada measured the buildup of carotid plaque in the arteries of 1,231 subjects. The men and women in the study were all patients at cardiovascular health clinics. For comparison’s sake, the team also measured the carotid plaque buildup of smokers in the study.

Plaque buildup increased according to age after age 40 in a fairly steady fashion. But among the 20 percent of participants who reported eating the most egg yolks – three or more per week – carotid plaque increased “exponentially,” according to the study. The buildup equaled about two-thirds of that seen among the heaviest smokers in the group.

Arterial plaque buildup is a major risk factor for heart attack and stroke; as plaque accumulates on artery walls, it narrows the space through which blood can pass, making the heart’s job of pumping more difficult. Moreover, plaque buildups can break away from the arterial wall, forming clots that can do terrible, even fatal, damage if they reach the heart or brain.

The role of dietary fat and cholesterol in cardiovascular health has been under investigation in recent years. It was once believed that eating cholesterol-rich foods led to high levels of cholesterol in the bloodstream, but that assumption’s been questioned recently. The Dietary Guidelines for Americans 2010 recommend consuming no more than 300 milligrams of dietary cholesterol daily. One medium egg contains 186 mg cholesterol, all of it in the yolk.

But the new study suggests that dietary cholesterol may be a more important heart-health factor among those at risk of cardiovascular disease or those whose cardiovascular health already is compromised. “We conclude that the prevailing tendency to ignore dietary cholesterol as a risk factor for coronary heart disease requires reassessment, including the consumption of cholesterol from eggs,” the study says.