An Old Woman Cooking Eggs

A Yo-Yo Diet of Misinformation About Eggs

Really? We’re going to do this again? In JAMA, a new pooled analysis of six observational studies found an association between eating more eggs and a higher risk of cardiovascular disease and death. This finding comes just four years after scientific experts reached a consensus that “cholesterol is not a nutrient of concern for overconsumption.” That conclusion comes from the Scientific Report of the 2015 Dietary Guidelines Advisory Committee.

We’re feeling a bit of whiplash.

A Pooled Analysis with Significant Limitations

This is a pooled analysis (not a meta-analysis) that found a significant association. Nothing more and nothing less. The findings are “important,” says Robert Eckel in an editorial alongside the study in JAMA. But he also says the strength of this association is “modest.”

The absolute risk difference in mortality linked to eggs was only 0.71%. The difference in heart disease risk was only 0.47%. When taking total dietary cholesterol into account, those differences were no longer significant.

In their paper, the authors list a number of limitations for their study. The most important one is that “the study findings are observational and cannot establish causality.” So we’re shocked to see the researchers turn around and issue a press release in which senior author Norrina Allen says just the opposite:

Our study showed if two people had 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.

Finding a stronger claim of causality than that would be hard to do.

Enjoy Your Eggs in Moderation

Sorry, but we are not ready to dismiss the carefully considered findings of the Dietary Guidelines Advisory Committee. It took a long time and a lot of research to get past some confusion about the difference between dietary cholesterol and blood cholesterol.

Professor Madelyn Fernstrom sums it up quite well for us:

You can relax. Eggs remain a nutrient-rich healthful choice, when eaten in moderation. While this study sounds strong, there are a lot of gaps in information and assumptions that can be both misleading and confusing.

Above all, this story is disappointing. How can it be so hard to keep a simple fact straight? A correlation does not prove a cause and effect relationship.

Click here for the study and here for Eckel’s editorial. For more perspective, click here for Fernstrom’s post on this and here for reporting by the New York Times.

An Old Woman Cooking Eggs, painting by Diego Velazquez / WikiArt

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March 16, 2019

3 Responses to “A Yo-Yo Diet of Misinformation About Eggs”

  1. March 16, 2019 at 9:18 am, Bryan said:

    Good post

  2. March 16, 2019 at 2:20 pm, Susan said:

    Thank you! The minute I read the New York Times article I wondered and hoped that you’d take a look.
    I sick and tired of professional journalists not doing their due diligence when reporting on science. They put more effort into covering the leader of our country’s toddler tantrums.
    Thanks for all you do, it matters.

  3. March 28, 2019 at 7:16 pm, steven t said:

    The 2015 guidelines said cholesterol is no longer a nutrient of concern because the average intake was 280mg/day, less than the prior recommendations . The Guidelines still advised eating “as little as possible of dietary cholesterol while maintaining a healthy eating pattern.” That is very different take.