There is conflicting evidence over whether egg consumption is beneficial or harmful to heart health. A 2018 study published in the journal Heart, which included approximately half a million adults in China, found that those who ate eggs daily (about one egg per day) had a substantially lower risk of heart disease and stroke than those who ate eggs less frequently.
Then in 2019 a study of 29,615 adults published by Northwestern University indicated that eating three to four whole eggs per week was associated with a 6 per cent higher risk of cardiovascular disease and an 8 per cent higher risk of any cause of death.
Eggs are a complete source of protein, vitamins A, E and B12, selenium, iron and cholesterol. It’s the presence of dietary cholesterol that causes the conflicting results. The Heart Foundation does not set a limit on the number of eggs you should eat a week. However, they advise that some people are more sensitive to eating dietary cholesterol than others, so recommend a maximum of seven eggs a week for those with high LDL cholesterol (bad cholesterol), type 2 diabetes and existing heart disease. What the Heart Foundation does says is what you eat with your egg matters, and that eggs and avocado on wholegrain toast is a healthy alternative to a bacon and egg roll.
To better understand the relationship between egg consumption and heart hearth, the authors of the 2018 study have carried out a further population-based study exploring how egg consumption affects markers of cardiovascular health in the blood.
“Few studies have looked at the role that plasma cholesterol metabolism plays in the association between egg consumption and the risk of cardiovascular diseases, so we wanted to help address this gap,” explains first author Lang Pan, from the Department of Epidemiology and Biostatistics, Peking University, China.
Their analyses showed that those who ate a moderate amount of eggs had higher levels of a protein in their blood called apolipoprotein A1 – a building block of high-density lipo-protein (HDL), also known as ‘good lipoprotein’. In particular, these people had more large HDL molecules in their blood, which help clear cholesterol from the blood vessels and thereby protect against blockages that can lead to heart attacks and stroke.
The researchers further identified 14 metabolites that are linked to heart disease. They found that participants who ate fewer eggs had lower levels of beneficial metabolites and higher levels of harmful ones in their blood, compared to those who ate eggs more regularly.
“Together, our results provide a potential explanation for how eating a moderate amount of eggs can help protect against heart disease,” says author Canqing Yu, Associate Professor at the Department of Epidemiology and Biostatistics, Peking University. “More studies are needed to verify the causal roles that lipid metabolites play in the association between egg consumption and the risk of cardiovascular disease.