Eating a dozen eggs a week doesn't hurt your cholesterol: Study

Eating more than a dozen fortified eggs each week did not negatively affect cholesterol levels compared to an egg-free diet among U.S. adults aged 50 or older, according to a new study to be presented at the American College of Cardiology's Annual Scientific Sessions in Atlanta.

The study adds evidence that eggs -- once vilified as an unwanted cause of high cholesterol -- could be part of a healthy and balanced diet, even for people with a higher risk of heart disease.

In the study, a total of 140 adults older than age 50, who also had heart disease or at least two risk factors for developing heart disease, followed either an egg-free diet (less than two eggs per week) or a diet of eating more than 12 fortified eggs each week. Fortified eggs contain additional amounts of vitamins (such as vitamin D) or omega-3 fatty acids, typically through nutrient-enriched hen feeds. The study participants' cholesterol levels were monitored at the beginning of the study, then again at four months.

Results did not show any meaningful change in levels of HDL ("good" cholesterol) or LDL ("bad" cholesterol) between these two groups, suggesting that eating at least 12 fortified eggs each week did not have any negative effects on cholesterol levels.

Fortified eggs were chosen as they may contain enriched levels of "vitamins D, B and E, omega- fatty acids, iodine along with lower saturated fat," wrote Dr. Nina Nouhravesh, research fellow at the Duke Clinical Research Institute in Durham, North Carolina, and the study's lead author.

Nouhravesh noted that in the study, among patients with "heart disease or at risk of developing heart disease, the consumption of 12 fortified eggs per week did not negatively impact their cholesterol over 4 months, when compared to patients who were on a non-egg supplemented diet."

"The urban myth out there is that eggs are bad for your heart. It's not a total myth, but we've known that guidelines for healthy eating took out previous advice to limit dietary cholesterol, because it really didn't make a big difference in overall cholesterol. The cholesterol is in the egg yolk," said Dr. James O'Keefe, Professor of Medicine at the University of Missouri-Kansas City and cardiologist at Saint Luke's Mid America Heart Institute.

"As we get older, we need higher amounts of protein to maintain muscle mass. Muscle mass and physical strength are two predictors for healthy aging. It's important to maintain and build muscle mass at middle age and beyond. Eggs are an inexpensive, widely available source of protein," said O'Keefe.

For most people, eggs are nutritious and an excellent source of protein. But medical experts say each person should speak to their health care providers about whether a diet heavy in eggs is appropriate given their individual cholesterol levels and dietary needs.

Dr. Jennifer Miao is a cardiology fellow at Yale School of Medicine/Yale New Haven Hospital and a member of the ABC News Medical Unit.