Eggs: Is an Egg a Day Harmful?

Latest study suggests frequent egg eaters die earlier

By Jeanie Lerche Davis
WebMD Medical News

Reviewed By Michael W. Smith, MD

July 28, 2004 -- Is the all-clear on eggs all over? A new Japanese study breaks through the promising news on eggs. Eating eggs every day increases a woman's risk of dying young, it says.

The report appears this month in the American Journal of Clinical Nutrition. The 14-year study shows that women who ate one egg a day were more likely to die during those 14 years compared with women who ate one to two eggs a week.

It stirs up an old argument -- whether the egg yolk's 200 mg of cholesterol contributes to health problems like heart disease.

Two years ago, a study published by the American Heart Association found that up to one egg per day did not have a significant impact on risk for heart disease or stroke. The AHA now recommends eating less than 300 mg per day on average. People with high cholesterol should eat no more than 200 mg per day.

But that's not all: Scientists have discovered something called phosphatidylcholine, or PC, a compound found naturally in eggs. It seems to block an egg's cholesterol from entering the bloodstream. And just this month, a group of Connecticut researchers found that adding up to three eggs per day raises some types of LDL "bad" cholesterol -- but not the type of LDL known to clog arteries.

Yet eggs are good food -- a highly digestible, excellent source of protein, lutein (a powerful antioxidant), vitamins A, E, and B, and folate.

Cracking the Data

The study involved more than 9,000 Japanese men and women whose egg consumption, cholesterol levels, and deaths were documented from 1980 to 1994.

Women who ate an egg daily were more likely to die early than women who ate one or two eggs per week. Total cholesterol level among the frequent egg eaters was on average 6 mg/dL higher than less-frequent egg eaters.

For men, frequent egg eating seemed to pose no problems to total cholesterol. Fewer men ate eggs every day, for one thing. And men who were daily egg eaters had no higher risk of early death than women.

How could this be? Possibly because this group of Japanese men got their total daily cholesterol from a wider variety of sources -- more so than the women did, writes lead researcher Yasuyuki Nakamura, MD, a cardiologist with the Shiga University of Medical Science in Japan.

One limitation of this study: The researchers did not document total calorie or cholesterol intake, or saturated or polyunsaturated fat intake.

The better odds for infrequent egg eaters may reflect a more "health-conscious" attitude that eventually results in better health and longer life. But since equal numbers of smokers were found in both groups of egg-eating women, that wasn't likely the case, writes Nakamura.

What Should We Do?

Egg lovers are getting whiplash -- trying to figure out one study, then another.

"Don't change your egg-eating habits just yet," Cindy Moore, MS, RD, director of nutrition therapy at The Cleveland Clinic, tells WebMD. "This study is in no way the final word."

"You can eat eggs a couple of times a week, depending on the animal meats you eat," she says. "If you eat very little meat, you can eat more eggs because they are a high-quality food. If you eat a lot of meat, you have to be more judicious about eggs. Also, if you have high cholesterol, you have to be more careful."

"It's never good to eat the same thing every single day," says Joseph Miller, MD, a preventive cardiologist at Emory University School of Medicine in Atlanta.

"Eating bagels every day is not good for you -- just like having eggs every day isn't good for you," Miller tells WebMD. "One or two eggs a week is plenty for anyone who is healthy. But if you have high cholesterol, I would advise eating less than that."

SOURCES: Nakamura, Y. American Journal of Clinical Nutrition; vol 80: pp 58-63. WebMD Medical News: "Eating Eggs Daily May Not Be Risky for Heart." WebMD Medical News: "Unscrambling the News About Eggs." WebMD Medical News: "Eggs Might Not Be So Bad After All."

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