By Elizabeth M. Ward, M.S., R.D.
Savvy consumers of health information know you can’t believe everything you hear. That’s especially true when it comes to this week’s reporting on research published in the journal Atherosclerosis that compares eating eggs to smoking.
The study generated some sensational stories that would have you believe egg yolks are as bad as cigarettes in raising the risk of coronary heart disease, but that’s probably not the case.
Beyond the Headlines
Researchers examined the relationship between eating egg yolks and the amount of plaque in the carotid artery in about 1,200 men and women. Plaque impairs blood flow and is considered a risk factor for coronary heart disease.
Cigarette smoking was also tallied and related to plaque levels. The effect of eating egg yolks and smoking on carotid plaque levels were compared to each other, resulting in headlines heralding the two behaviors as nearly equally risky, which is misleading, experts say.
According to Chris Mohr, PhD, RD, the design of the study does not allow for a conclusion about egg yolks’ link to heart disease.
“This was a correlation study, based on self reporting from the subjects,” says Mohr, owner of MohrResults.com, based in Louisville, Kentucky. “Correlation doesn’t mean causation because it’s next to impossible to control for so many other factors” that may influence the health of your arteries, Mohr contends.
Indeed, the authors acknowledged the study’s observational nature as one of its flaws.
“No study is perfect, but this one left me with way more questions than answers,” Mohr says.
I agree. The study did not ask people to report on other dietary and lifestyle factors that influence plaque buildup. For example, I found myself wondering about saturated fat and fiber consumption, and physical activity levels.
A remark made by the researchers in the study may provide a glimpse into study subjects’ eating habits. The researchers cite having a large number of high-risk patients with “significant egg consumption despite recommendations to limit egg consumption” who participated in the study. The dietitian in me thinks that many of the patients, already at risk for heart disease, didn’t adhere to dietary advice designed to help them manage the condition.
Should you eat eggs?
In a word, yes.
This is a single, observational study that does not prove cause and effect and does not change the fact that more than 40 years of research suggests that healthy people can eat eggs without having a significant impact on their risk for heart disease. According to the Harvard School of Public Health, most healthy people can have a whole egg every day as part of a balanced diet, while those with diabetes and heart disease should limit egg yolks to three a week.
Eggs are a great source of many nutrients, and one of the most affordable sources of protein around, says Mohr. Eggs provide 13 essential vitamins and minerals and antioxidants for relatively few calories. Nearly all of the nutrients, and about half of the protein, is in the yolk.