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The egg yolk is full of cholesterol.
The egg yolk is full of cholesterol. Mara Zemgaliete/stock.adobe.co

Wait a second, eggs are bad again?

A new study finds that the beloved egg, which recently had regained some of its luster, may not be all that it’s cracked up to be.

Researchers at Northwestern Medicine say a large new study has found that adults who ate more eggs and cholesterol had a significantly higher risk of cardiovascular disease and death from any cause.

“The take-home message is really about cholesterol, which happens to be high in eggs and specifically yolks,” Norrina Allen, associate professor of preventive medicine at Northwestern University Feinberg School of Medicine and one of the authors of the study, said in a statement. “As part of a healthy diet, people need to consume lower amounts of cholesterol. People who consume less cholesterol have a lower risk of heart disease.”


The study was published Friday in the journal JAMA. The lead author was Wenze Zhong, a postdoctoral fellow in preventive medicine at Northwestern.

Whether eating eggs or cholesterol, which is also found in products such as red meat, processed meat and high-fat dairy products, is linked to cardiovascular disease and death has long been a subject of debate, the researchers said.

Government dietary guidelines for decades said people should eat less than 300 milligrams of cholesterol per day. But in a big boost for eggs, guidelines instituted in 2016 omitted the limit and included weekly egg consumption as part of a healthy diet.

The change in the dietary guidelines came as critics questioned whether the government has issued advice in the past that had proven unnecessary or exaggerated, The Washington Post reported. An expert panel said cholesterol was no longer “a nutrient of concern.”

But the Northwestern researchers said their study suggests those guidelines may have to be looked at yet again. That’s because the average US adult now gets 300 milligrams of cholesterol a day and eats three or four eggs a week — and data indicate it’s bad for them.


Eating 300 milligrams of cholesterol a day was associated with a 17 percent higher risk of cardiovascular disease incidents (stroke and heart attack, for example) and 18 percent higher risk of death generally, researchers said.

They also found that eating three or four eggs a week was associated with a 6 percent higher risk of cardiovascular disease incidents and 8 percent higher risk of death generally.

One large egg has 186 milligrams of cholesterol in the yolk.

The researchers said their study looked at nearly 30,000 racially and ethnically diverse US adults from six separate studies with an average of about 17 years of follow-up. The participants self-reported their food intake.

The researchers suggested that people don’t have to ban eggs and other cholesterol-rich foods from their diets because they do contain important nutrients. They just suggest cutting back.

“We want to remind people there is cholesterol in eggs, specifically yolks, and this has a harmful effect,” Allen said. “Eat them in moderation.”

“Our study showed if two people had the exact same diet and the only difference in diet was eggs, then you could directly measure the effect of the egg consumption on heart disease,” Allen said. “We found cholesterol, regardless of the source, was associated with an increased risk of heart disease.”

Dr. Bruce Lee of Johns Hopkins University, said nutrition studies are often weak because they rely on people remembering what they ate.


‘‘We know that dietary recall can be terrible,’’ said Lee. The new study offers only observational data but doesn’t show that eggs and cholesterol caused heart disease and deaths, said Lee, who wasn’t involved in the research.

Dr. Frank Hu of Harvard University noted that most previous studies have shown that eating a few eggs weekly is not linked with risks for heart disease in generally healthy people.

‘‘I don’t think that this study would change general healthy eating guidelines’’ that emphasize fruits, vegetables, whole grains, nuts and beans and limiting processed meats and sugar, Hu said. Eggs, a breakfast staple for many, can be included but other options should also be considered, ‘‘like whole grain toast with nut butter, fresh fruits, and yogurt,’’ Hu said.

Dr. Rosalind Coleman, a professor of nutrition and pediatrics at the University of North Carolina, offered broader advice.

‘‘The main message for the public is not to select a single type of food as ‘bad’ or ‘good’ but to evaluate your total diet in terms of variety and amount.

‘‘I'm sorry if it seems like a boring recommendation,’’ she added, but for most people, the most important diet advice ‘‘should be to maintain a healthy weight, to exercise, and to get an adequate amount of sleep.’’

Material from The Associated Press was used in this report. Jeremiah Manion of the Globe staff contributed to this report.