One egg per day may keep stroke at bay

Popular knowledge has it that eggs, due to their high cholesterol content, are quite bad for us. New research, however, suggests we would do well to indulge in more egg consumption: about one per day could help us to steer clear of cardiovascular conditions.
We might think of eggs as unhealthful, but could they protect against cardiovascular events?

If you've ever heard that eating more than two or three eggs per week is bad for your health, you're not alone.

Some studies have suggested that, due to yolks' high cholesterol content, eggs can be a harmful food — particularly for people already at risk of cardiovascular events.

The idea that eggs may pose danger to health has also been spread widely by many popular websites and magazines.

However, despite being rich in cholesterol, eggs are also a great source of healthful nutrients, such as protein, vitamins, phospholipids, and carotenoids.

And, recent research has increasingly gathered evidence showing that eggs don't really influence the risk of cardiovascular disease (CVD).

One study published in 2013 in The BMJ, for example, concluded that eating up to one egg per day was not tied to a heightened risk of heart disease or stroke.

Another study, published earlier this month in the American Journal of Clinical Nutrition, suggested that a "high-egg diet" of up to 12 eggs per week did not increase cardiovascular risk.

But recent research from the School of Public Health at Peking University Health Science Center in Beijing, China, goes even further.

Lead investigators Prof. Liming Li and Dr. Canqing Yu have now found that a diet in which eggs are consumed on a regular basis may actually protect cardiovascular health.

The team's findings were published yesterday in the journal Heart.
'Moderate egg consumption' may lower risk

About 84 million people in the United States have some form of CVD, and about 2,200 people die each day due to their condition. And, in China, the rates for cardiovascular conditions are even higher.

In China in 2014, an estimated "837,300 urban residents and 1,023,400 rural residents died from cerebrovascular diseases," according to recent data. And the most widespread conditions are stroke — both hemorrhagic and ischemic — and ischemic heart disease, in that order.

These numbers motivated the researchers involved in the new study to investigate what role — if any — egg consumption plays in modifying the risk for CVD.

In order to do so, they analyzed data sourced via the China Kadoorie Biobank, which is an ongoing prospective study investigating the genetic and environmental causes of chronic diseases among the Chinese population.

In this study, Prof. Li and team analyzed health-related information from 416,213 adult participants recruited in 2004–2008. They were all free of cancer, CVD, and diabetes at baseline.

At recruitment, the participants reported how often they ate eggs — 13.1 percent of them admitting to daily consumption (about 0.76 eggs per day) and 9.1 percent saying that they only indulged in eggs rarely (0.29 eggs per day) or not at all.

There was a median follow-up period of 8.9 years, during which new health diagnoses and deaths were recorded. During that time, 83,977 participants received a CVD diagnosis, and 9,985 people died due to CVD-related causes. Moreover, 5,103 major coronary events were recorded.

The researchers' analysis revealed that individuals who usually ate about one egg per day had a 26 percent lower risk of experiencing hemorrhagic stroke, a 28 percent lower risk of death due to this type of event, and an 18 percent lower risk of CVD-related mortality.

Almost daily egg consumption — or around 5.32 eggs per week — was also linked to a 12 percent lower risk of ischemic heart disease, compared with people who never or rarely ate this food (amounting to approximately 2.03 eggs per week).

"The present study finds that there is an association between moderate level of egg consumption (up to 1 egg/day) and a lower cardiac event rate," the study authors explain.

Prof. Li and team warn that this was an observational study, so it would be unwise to conclude that there is necessarily a causational effect between egg consumption and a lower risk of CVD.

However, the large population sample size with which the researchers worked, as well as the fact that they adjusted for confounding factors — both known and potential CVD risk factors — imply that this is a strong possibility.

"Our findings," the researchers conclude, "contribute scientific evidence to the dietary guidelines with regard to egg consumption for the healthy Chinese adult."