Does an egg a day keep CVD away?

By John Murphy, MDLinx
Published December 5, 2018

Key Takeaways

For many years, eggs have had a bad reputation for contributing to heart disease. But new research is turning this “bad egg” into a good one. Indeed, researchers of a recent study showed that eating an egg a day is actually associated with a lower risk of cardiovascular disease (CVD) vs eating no eggs. Now who has egg on their face?

Over the years, studies that have investigated the association of eggs with CVD have yielded mixed results. To gain further clarity on the matter, researchers in China and the United Kingdom further examined this association by studying data on more than half a million (512,891) adults (aged 30-79 years) from different areas in China.

When the researchers asked participants about their egg consumption at the start of the study, 13.1% reported eating eggs daily (usual amount, 0.76 egg/day) and 9.1% reported never or very rarely eating eggs (usual amount, 0.29 egg/day).

Eggs-emplary cardiac results

By the end of the study, as the researchers recently reported in Heart, they found that daily egg consumption was associated with a lower risk of CVD (HR: 0.89, 95% CI: 0.87-0.92) compared with never or rarely eating eggs.

Notably, daily egg consumers had a 26% lower risk for hemorrhagic stroke (which has a high prevalence rate in China), a 28% lower risk for hemorrhagic stroke death, and an 18% lower risk for CVD death.

In addition, daily egg consumption was associated with a 12% lower risk for ischemic heart disease and a 14% lower risk for major cardiac events compared with not eating eggs.

“The present study finds that there is an association between moderate level of egg consumption (up to

The authors acknowledged that, because this was an observational study, their findings can’t prove cause and effect.

A short eggs-planation

Long before this study, dieticians and physicians warned people away from eggs because of their high cholesterol content. Indeed, one egg typically contains 141-234 mg of dietary cholesterol, and eggs are the number one food source of cholesterol in the US population.

Until recent years, the US government’s Dietary Guidelines for Americans recommended limiting daily dietary cholesterol intake to 300 mg for healthy individuals and 200 mg for people with CVD or at high risk for CVD. These recommendations were removed when new guidelines were published in 2015, but the new guidelines still advise eating as little dietary cholesterol as possible while following a healthy eating pattern.

The whole hullabaloo started in 1968 when the American Heart Association recommended that everyone reduce their dietary cholesterol to less than 300 mg per day and eat no more than three whole eggs per week.

“In 1968 who knew what 10% of calories from saturated fat or 300 mg cholesterol actually meant?” wrote Donald J. McNamara, PhD, former executive director, Egg Nutrition Center, in a 2015 article in Nutrients.

What it meant, at that time, was that high dietary cholesterol equaled high blood cholesterol, which equaled high CVD risk, Dr. McNamara explained.

But since then, he added, investigators who have studied dietary lipids and CVD incidence have shown that dietary cholesterol is not an independent risk factor for heart disease.

For instance, in a just-released study, investigators showed that older adults who ate 12 eggs per week for 1 year developed no significant changes in fasting serum lipids, lipoprotein cholesterol, or other biomarkers of CVD, compared with baseline concentrations.

“Half a century of research have shown that egg and/or dietary cholesterol intake is not associated with increased CVD risk,” wrote Dr. McNamara in his article. “In addition, research studies have shown that egg intake addresses a number of nutrient inadequacies and can make important contributions to overall health across the life span.”

So, go ahead, eat your eggs (but, unfortunately, hold the bacon).

Funding for the first study mentioned was supported by the National Natural Science Foundation of China, National Key Research and Development Program of China, the Kadoorie Charitable Foundation, the UK Wellcome Trust and the Chinese Ministry of Science and Technology. Funding for the second study was supported by the American Egg Board, the Egg Nutrition Center, and the Massachusetts Lions Eye Research Fund Inc.

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