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Don’t Scramble Diet Over Eggs and Heart Study


May 22, 2018 -- Could an egg a day keep heart disease away, despite warnings in the past that the cholesterol was bad for your heart? Chinese researchers suggest it might, after their study following more than 400,000 adults for about 9 years found an egg a day lowered the chance of heart disease and strokes.

"Among Chinese adults, a moderate level of egg consumption, up to less than an egg a day, was significantly associated with lower risk of cardiovascular disease," the researchers report in the journal Heart.

In the study, eating an egg daily lowered the odds of dying from heart disease by 18% and cut the risk of hemorrhagic stroke by 28%, when compared with those who never, or rarely, ate eggs. This was true even after the researchers took into account other things that could affect risk, such as diet and exercise. Hemorrhagic strokes happen when a blood vessel in the brain bursts.

But U.S. consumers should take the egg news with a grain of salt, says Alice Lichtenstein, DSc, Gershoff professor of nutrition science and policy at the Cardiovascular Nutrition Laboratory at Tufts University in Boston. She was not involved in the study.

"It's an interesting study, but we can't really draw conclusions [for the U.S.] because they consumed so little cholesterol,'' says Lichtenstein, who is also a spokeswoman for the American Heart Association. She says most of the Chinese participants actually ate few eggs.

What the Study Found

From 2004 through 2008, the researchers from Peking University Health Science Center in Beijing and other institutions recruited more than a half million Chinese adults, ages 30 to 79, from 10 sites in China. They disqualified those who had a history of cancer, heart disease, stroke, or diabetes, ending up with more than 400,000 people. They asked all participants how many eggs they ate and how often.

At the start of the study, about 13% of the participants reported eating eggs every day -- three-fourths of an egg, on average. And 9% said they never or rarely ate eggs, eating on average a quarter of an egg daily. Overall, the average among all participants was about half an egg a day.

The researchers tracked which of the participants had heart disease or strokes over the 9-year follow-up period. They found nearly 84,000 cases of heart disease or stroke. Almost 10,000 died from heart disease or stroke.

Why the Link?

The study found an association, or link, but cannot prove cause and effect. The researchers cite other research that found cholesterol from eggs had no net effect on the chance of having heart disease. They say other things that are in eggs could help explain the link they found with heart health.

But the scientists also note the study’s limitations, such as relying on people to remember and record what they ate, which is always subject to error.

Over the years, the issue of eggs and heart health has been controversial.

Advice for U.S. Egg Lovers

"I don’t think we can use these data to say what the implications could be for the U.S. population," Lichtenstein says. Their highest group was eating less than an egg a day, she says.

So what to do? "The current data suggest if you would like to have an egg every day or a couple eggs every other day, that is fine for most individuals," she says.

Use that information and your doctor's guidance to decide how many eggs to eat, she says.

"There is no convincing research data that indicates one egg a day is problematic," says Teresa Fung, ScD, RD, adjunct professor of nutrition at the Harvard T.H. Chan School of Public Health."What would be  problematic is how the egg is prepared and what else is consumed a day. An egg a day in the form of bacon and egg breakfast sandwich would be problematic.''

An egg has 70 calories, 6 grams of protein, 1.5 grams of saturated fat, and 185 milligrams of cholesterol, the American Egg Board says.

Under the 2015 Dietary Guidelines for Americans, dietary cholesterol is not viewed as a ''nutrient of concern for overconsumption." Previous guidelines recommended having no more than 300 milligrams of cholesterol a day. The new guidelines say evidence shows ''no appreciable relationship'' between cholesterol in your diet and your blood levels of cholesterol.

WebMD Health News Reviewed by Arefa Cassoobhoy, MD, MPH on May 22, 2018


BMJ Heart: "Associations of egg consumption with cardiovascular disease in a cohort study of 0.5 million Chinese adults."

Alice Lichtenstein, DSc., Gershoff professor of nutrition science and policy, and director and senior scientist, Cardiovascular Nutrition Laboratory, Tufts University JM USDA Human Nutrition Research Center on Aging, Boston.

American Egg Board: "Egg Nutrition."

2015 Dietary Guidelines for Americans.

Teresa Fung, ScD, RD, adjunct professor of nutrition at the Harvard T.H. Chan School of Public Health.

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