Do eggs raise your risk of heart disease and death?

Eating more eggs has been linked to a higher risk of heart and circulatory disease and death, but is this the full picture? We look behind the headlines and give the BHF’s view.

Eggs have long been a topic of debate when it comes to healthy eating. But in recent years the consensus from experts has been that although eggs contain cholesterol, it’s saturated fat rather than cholesterol that really affects the cholesterol levels in our blood, so it’s fine to eat eggs as part of a healthy diet.

But research published in February 2021 appears to question this.

The study, led by Zhejiang University in China, aimed to look at the link between the amount of eggs you eat, your cholesterol intake, and death rates. It was a large study of 521,120 Americans.

The researchers asked participants how often they ate different foods, including whole eggs and egg whites. They used this information to estimate their cholesterol intake.

The study found a link between eating more eggs and higher total risk of death, as well as death from heart and circulatory disease and from cancer. But the reverse was true when it came to eating egg whites only.

The study also found that eating more cholesterol was associated with a higher total risk of death, as well as death from heart and circulatory disease and from cancer. Each intake of an additional 300mg a day of dietary cholesterol (roughly the amount found in one and a half medium eggs) was associated with 19 per cent higher all-cause mortality, 16 per cent higher risk of death due to CVD and 24 per cent higher risk of death due to cancer.

The researchers estimated that most of the increased risk found from eating more eggs is explained by the cholesterol in the eggs. They also found an apparently stronger link with death from heart and circulatory disease (and from diabetes) when the eggs were not fried. They suggest this could be because most eggs were fried in vegetable oil, which is a healthier type of fat.

The researchers said that replacing whole eggs with an equivalent amount of egg whites, or other healthy sources of protein such as poultry, fish, nuts or pulses could help to reduce risk of death.

How good was the research?

A weakness of the study was that it relied on the answers of a self-completed questionnaire that asked people to remember what they’d eaten the year before. It’s unlikely that all the participants in the study could accurately remember this, so it makes the research results less reliable.

The participants were followed up for 16 years on average, but they didn’t complete any other questionnaires in this time. Their eating habits could have changed over that period, so the study findings may not be accurate.

This kind of study is observational: which means it can’t prove cause and effect, in this case whether the differences seen were definitely caused by eggs.

When it comes to eating for our heart and circulatory health, it's our overall diet which is most important

There could have been other differences in the lifestyle of the people who ate more eggs which explained these results. Although the researchers adjusted the results to take known differences into account (for example, those who ate more eggs were more likely to be overweight), it’s possible that they didn’t take everything into account.

This study conflicts with some previous research which has suggested that eating eggs does not affect heart health or risk of death, and other research which has not found a clear link between cholesterol in the foods we eat and with heart disease or stroke.

The BHF view

Victoria Taylor, Senior Dietitian at the British Heart Foundation, said: “More research would be needed to confirm these findings.

“Reports suggesting that certain foods are bad for us can be worrying, but when it comes to eating for our heart and circulatory health it’s our overall diet that is most important. Keeping meals varied and balanced and rich in foods we know we should be eating more of – like fruits, vegetables, pulses, wholegrains, fish, nuts and seeds – is a healthy approach.”

How accurate was the media coverage?

The story was covered widely in the media, including in Metro, Daily Mail, The Sun and iNews.

The Mail article says: “Chinese researchers who led the study believe high fat and cholesterol levels in eggs are to blame.” Actually, the total fat and saturated fat content in eggs is classed as medium rather than high, and the researchers suggest the cause is the cholesterol in eggs, but don’t suggest fat is to blame."

It's also not until the end of the article that the Daily Mail includes some quotes from experts suggesting that we shouldn’t read too much into this research. Including this kind of perspective earlier on in the article might have been more useful.

The Sun headline and first sentence said “eating just three eggs a week can raise your risk of dying young”. The study was carried out on an older population, aged 50 to 71 when first recruited and followed up for an average of 16 years. So the study does not tell us very much about the risk of dying “young”.

Published 10 February 2021