Are eggs off the menu again?

Whenever there’s a new study claiming a certain food is or isn’t good for our health, there are always critics who say “just wait — in other year or two there will be a study that says just the opposite.”

And they would be right. Case in point: a new study out of the University of Western Ontario is once again questioning whether eggs are a healthy food or not.

You may recall eggs used to have a bad reputation and we were told to limit our consumption to two eggs per week. Further studies then told us this restriction was unnecessary — it was a myth that eggs negatively affect heart health. Eggs have even been touted as a superfood because they’re a good source of protein and they contain unsaturated fats and nutrients like choline (which is linked to brain health) and lutein and zeaxanthin (thought to be food for the eyes. Current thinking is that we can safely enjoy an egg a day.

Now a new study published online in the journal Atherosclerosis may have the pendulum swinging back again. Headed by UWO researcher Dr. David Spence and director of the Robarts Research Institute’s Stroke Prevention and Atherosclerosis Research Centre, the study found that regularly consuming egg yolks over a long period of time is about two-thirds as bad as smoking when it comes to atherosclerosis. This build-up of plaque is a known risk factor for heart disease and stroke.

The study analyzed data from 1,231 men and women — with a with a mean age of 61.5 — who were patients at the vascular prevention clinics at London Health Sciences Centre’s University Hospital. Researchers used questionnaires to find out about lifestyle habits such as how often patients smoked and consumed egg yolks. Ultrasounds were used to measure the amount of plaque in participants’ veins.

The findings: in all participants, carotid plaque amounts increased linearly with age starting about age 40. (A fairly gradual increase.) However, among people who smoked or who regularly consumed egg yolks, the amount of plaque increased exponentially. Researchers found that like smoking, regular egg yolk consumption accelerated atherosclerosis beyond the normal rates we could expect with age.

The problem? The high amount of cholesterol in the eggs — a whopping 237 mg in a jumbo egg.

“The mantra ‘eggs can be part of a healthy diet for healthy people’ has confused the issue,” said Dr. Spence in a recent UWO press release. “It has been known for a long time that a high cholesterol intake increases the risk of cardiovascular events, and egg yolks have a very high cholesterol content. In diabetics, an egg a day increases coronary risk by two to five-fold.

“What we have shown is that with aging, plaque builds up gradually in the arteries of Canadians, and egg yolks make it build up faster — about two-thirds as much as smoking. In the long haul, egg yolks are not okay for most Canadians.”

So where does this leave us? Remember, this data comes from a single study that’s part of a much larger body of research. You’ve likely noticed that the participants were already being seen by doctors for cardiovascular issues. Dr. Spence notes that more investigation needs to be done to consider factors such as exercise and waist circumference. In the meantime, he recommends that people at risk for cardiovascular disease should avoid consuming egg yolks on a regular basis.

However, don’t expect to see a consensus on this issue any time soon. The study already has its critics, like Karen Harvey, registered dietician and nutrition officer with Egg Farmers of Canada

“We have decades of clinical research demonstrating no link between egg consumption and an increased risk of heart disease,” said Harvey in an interview with CBC News.

Of course, critics such as Dr. Spence aren’t persuaded and claim that the public doesn’t have the whole story from the industry group. Keep your eyes peeled, however — more dieticians and experts are bound to weigh in.

Unfortunately, there are no easy answers here. Perhaps “all things in moderation” is still the best advice? As always, talk to your doctor if you’re concerned about something you hear in the news before you make dietary or lifestyle changes.

In the meantime, will this study stop you from enjoying eggs? Tell us in the comments.

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For more information about the study, read the report from the CBC.