How Many Eggs Should I Eat? Huge Study Links Dietary Cholesterol to Heart Disease

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The potential negative health effects of eggs have been up for debate for decades. Getty Images

Eating eggs has been linked to a higher risk of cardiovascular disease and death in a study that's sure to reignite the debate on whether eggs damage heart health.

Eggs are the biggest source of dietary cholesterol in the Western diet, with the average large 50 gram egg containing approximately 186 milligrams of cholesterol, according to a recent study published in the journal JAMA. On average, the study participants consumed 241 milligrams of cholesterol per day.

The researchers found consuming 300 milligrams of dietary cholesterol per day was associated with a 17 percent increased risk of cardiovascular disease, and an 18 percent risk of what is known as all-cause mortality (dying from any cause).

An individual who ate three to four eggs per week appeared to have an 8 percent higher risk of all-cause mortality, and a 6 percent higher risk of cardiovascular disease. The findings could be worrying for the average American, who eats between three to four eggs per week, according to the study.

"According to our study, there is no 'safe' amount [of cholesterol to consume," lead author Victor Wenze Zhong, postdoctoral fellow in the department of preventive medicine at the Feinberg School of Medicine, Northwestern University, told Newsweek. "Any additional intake is associated with increased risk of cardiovascular disease and death," he said.

Zhong told Newsweek that the team was surprised to find the risks associated with eating eggs and other cholesterol-rich foods were apparent even in those who ate relatively healthy diets.

"This suggests limiting foods rich in dietary cholesterol, such as eggs, may be important to consider when choosing a healthy eating pattern," he said.

For decades, experts have debated whether the cholesterol present in eggs outweighs their health benefits. Most recently, the 2015-2020 Dietary Guidelines for Americans stated that cholesterol wasn't a concern, but that individuals should "also eat as little dietary cholesterol as possible."

The findings stand in contrast to past studies that suggested cholesterol had little to no association with heart disease, and that saturated fat carried the greatest risk, Lauri Wright, spokeswoman for the Academy of Nutrition and Dietetics, who did not work on the study, told Newsweek.

Cholesterol is a fat-like substance created by the liver. "Good" cholesterol made by the body helps with digesting food and making hormones. "Bad" cholesterol—often found in animal products such as eggs, meat, and dairy products—has been linked to coronary heart disease, stroke and heart failure. As heart disease kills around 610,000 Americans each year, accounting for one in four deaths, understanding the role played by food such as eggs is important.

The researchers evaluated 29,615 participants with an average age of 51, who took part in six separate studies in the U.S. The median follow-up time across the studies was 17.5 years, with the longest time being 31 years. In that time, 5,400 people experienced a cardiovascular event and 6,132 died.

Zhong, however, emphasized that the study was observational and couldn't prove dietary cholesterol or egg intake could cause cardiovascular disease or death. And the results might not relate to populations in other regions, particularly low and middle-income countries.

Zhong also warned that avoiding eggs and cholesterol-rich foods could lead to an "imbalanced and unhealthy diet" as eggs and red meat "can be good sources of many important nutrients such as essential amino acids, iron, and choline.

"A more appropriate recommendation would be eating egg whites instead of whole eggs or eating whole eggs in moderation, for the purpose of reducing risk of cardiovascular disease and death," he said.

Wright praised the researchers for using a large sample of people, and taking into account unhealthy risk factors, such as saturated fat intake, when assessing the data.

However, she told Newsweek, "Factoring dietary cholesterol together with egg consumption was somewhat 'stacking the deck' statistically speaking," but added that the study was still "very well-designed."

Aisling Pigott, a spokesman for the British Dietetic Association who was not involved in the study, told Newsweek: "I think it's important not to panic too much, this is showing us that we need to examine our understanding a bit more.

"The old advice still stands, eggs in moderation are absolutely fine as a useful source of protein. There is no safe or unsafe amount [to eat] but I do like the saying an egg a day is OK."