A new Greek study asserts that eating one to three eggs a week can reduce the risk of cardiovascular disease by more than half.
The study described the 10-year cardiovascular effects of self-reported egg consumption.
The healthfulness of eggs is a controversial subject.
One expert told Medical News Today that there are significant issues with the self-reported data on which the new study is based.

A recent study published in Nutrients explored how egg consumption affects one’s heart health, and the paper’s authors reported a striking finding.

The study suggests eating one to three eggs a week is associated with a 60% lower risk of developing cardiovascular disease.

In fact, the study found an even lower risk of developing cardiovascular disease, 75%, for those eating four to seven eggs a week. However, they only found a protective role in eating one to three eggs a week after considering sociodemographic, lifestyle, and clinical factors. The authors concluded that egg consumption may have a protective role against cardiovascular disease when included in healthy diet with low consumption of saturated fatty acids.

Egg consumption and heart health

There is plenty of research investigating the healthfulness of eggs, particularly with regard to heart health. However, the findings have been contradictory. Several studies, including 2019 researchTrusted Source, found that consuming eggs actually increases cardiovascular risk. And a previous review study sought to summarize and clarify the science, its title asking tongue-in-cheek, “Are eggs good again?”

Eggs deliver high quality nutrients, such as proteins, minerals, fat-soluble vitamins, iron, and carotenoidsTrusted Source. At the same time, they also contain high levels of saturated fatty acids and significant amounts of cholesterol, which are considered bad for the heart.

As a result, it is difficult to determine whether eggs are good for your heart or bad.

The new study surveyed healthy men and women living in Greece’s greater metropolitan Athens area regarding their egg-consumption habits. For the 1,514 men in the study, the mean age was 46, plus or minus 13 years. For 1,528 women, it was 45, plus or minus 14 years.

The survey began in 2001 with 3042 participants. The final 2011-2012 follow-up health assessments included 2020 of these individuals.

Researchers asked participants to self-report their monthly consumption of eggs, either alone or as recipe ingredients. They then divided these figures into weekly consumption levels.

Limitations of self-reported data

One of the authors of the review study noted above is Dr. Angela Zivkovic, associate professor and leader of the Zivkovic Lab at the University of California, Davis. Dr. Zivkovic was not involved in the current study.

Dr. Zivkovic pointed out to Medical News Today that the self-reported nature of the new study’s data calls its findings into question:

“Ask yourself how well you remember what you ate for breakfast two days ago, much less six months ago, unless you happen to be someone who eats the exact same thing for breakfast each day.”

In addition, “Depending on how well people actually remember what they ate and/or feel like they should report because of what they think they’re ‘supposed to’ eat,” added Dr. Zivkovic, “you may be reporting more on the psychology and memory than the actual food intake.”

Dr. Zivkovic also cited the lack of nutritional context offered in the study, saying, “The really important question is ‘what were the people who reported eating one to three eggs per day not eating?'”

The new study doesn’t capture the foods eggs replaced, such as red meats, bread, or even vegetables. Based on participants’ saturated fat levels, Dr. Zivkovic suspected they were likely eating less red meat or other saturated fat-rich meats.

Michelle Routhenstein, cardiology dietitian and preventive cardiology nutritionist at EntirelyNourished, agreed that the satiating nature of eggs “may help individuals consume more intentionally, and not consume other processed or refined foods that can lead to an increase in cardiovascular risk.” Routhenstein was not involved in the study.

Without such context, it is difficult, Dr. Zivkovic said, to know what the researchers were really seeing. “That context is everything.” She described a follow-up study to this research as an example of context’s importance:

“If I designed the study such that people were fed three eggs for dinner in the intervention group and the control group ate pork sausages instead, you would probably find the group eating eggs had reduced risk. But if the control group ate a salad loaded with carotenoid-rich vegetables with egg white as the protein source, you might find the salad group as the one with the reduced risk.”

Are eggs good for heart health?

According to Dr. Zivkovic, health is not based on single foods but on one’s entire diet.

“Can eggs be a part of a healthy diet that is consistent with the prevention of heart disease? Absolutely. [Are they] the right choice for everyone? No.”

It is true, Routhenstein explained, “Eggs are… a rich source of Vitamin B2, B12, and selenium, which are cardioprotective.” The Vitamin B2 and B12 they contain, she added, can help normalize homocysteine levels that, when elevated, may result in arterial plaques. Routhenstein also credited eggs’ selenium for helping to combat the oxidative stress that is a main component of heart disease.

More good news, said Dr. Zivkovic, is that interventional studies find that “eggs do not increase total cholesterol, and can, in fact, improve the cholesterol efflux capacity of HDL [cholesterol] particles.”

“But the high cholesterol and choline content of eggs may be a problem for certain individuals who are at risk for heart disease.” said Routhenstein. “So, while eggs may be able to be included in a heart healthy diet, the amount should be relatively limited. The whole diet should be evaluated for optimal risk reduction.”

What to know about atherosclerosis

Atherosclerosis happens when arteries become narrow and hard due to a buildup of plaque around the artery wall.

Other terms for the conditionTrusted Source include arteriosclerosis and hardening of the arteries.

The plaque that is the cause of atherosclerosis consists of cholesterol, calcium, fat, and other substances, and it can harder over time.

The changes in a person’s arteries disrupt the flow of blood around the body and increase the risk of complications, such as heart attack or stroke. These complications can be life threatening.