Eggs as a Case Study for Knowledge Transfer

30 Apr

Written by: Megan Arppe-Robertson

Image courtesy of Megan Arppe-Robertson.

Image courtesy of Megan Arppe-Robertson.

The story of egg nutrition has been a scrambled one over the decades. This controversy was brought to light again last summer when new egg yolk research was published by Spence et al. in the academic, peer-reviewed journal Atherosclerosis (August 2012).  The authors reported that, after age 40, carotid plaque area (an indicator of atherosclerosis) increased linearly with age, but increased exponentially with smoking or egg yolk consumption.  Adult men and women who consumed 4-5 egg yolks per week had two-thirds the atherosclerotic effect as those who had smoked the equivalent of a pack a day for 40 years (1).  In an article published by his University’s online news service, Dr. Spence was quoted as saying that the findings demonstrate that “eating egg yolks accelerates atherosclerosis in a manner similar to smoking cigarettes” and “in the long haul, egg yolks are not okay for most Canadians” (2).

His oversimplified message did not help to mitigate media sensationalism, and they jumped on the comparison of egg yolk consumption to smoking.  Over the next couple weeks, media outlets around the world published stories with headlines such as Egg yolks almost as dangerous as smoking, researcher says (3), No yolk: eating the whole egg as dangerous as smoking? (4), and Eating egg yolks as ‘bad as smoking’ (5).

Interestingly, most research has not supported the link between egg yolks and cardiovascular disease. For example, the Physicians’ Health Study and a Harvard School of Public Health study both found that consumption of up to 7 eggs per week has no association with heart failure (6), coronary heart disease, or stroke (7).  However, this other side of egg yolk research (the sunny-side, perhaps?), has not been nearly as well represented in the media, possibly due to the less shocking headline opportunities.

To my surprise (and relief), not everyone was eating up the media’s negative commentary on eggs.  Hundreds of comments were posted in response to online articles and dozens of blog posts were written on this subject. The perspectives ranged from sarcastic, to anecdotal, to scientifically critical. The public pointed out valid limitations of the study, including that the study design revealed association not causation, that consumption patterns were collected retrospectively and only for eggs (not for any other foods), and that confounding lifestyle factors beyond smoking such as waist circumference, exercise and alcohol consumption were not considered.

So what can we learn from this story?  Effective and accurate knowledge transfer requires effort from all parties. Translating research findings is becoming a key objective for granting agencies, and how to effectively transfer knowledge to the public is an area that still requires development.  Researchers should interpret their results carefully to the media and provide the public with context for their findings. Media should commit to reporting accurately, focusing on making research applicable to the public instead of attempting to shock.  Finally, the public should be conscious consumers and think critically about both research and the context in which it is reported.  Together, insightful knowledge translation and transfer and an informed public can ensure accurate information is disseminated, allowing a population to be empowered by research findings.


1. Spence, J.D., Jenkins, D.J.A., and Davignon, J.  (2012).  Egg yolk consumption and carotid plaque.  Atherosclerosis, e1-5.

2. Communications Staff.  (2012, August 13).  Research finds egg yolks almost as bad as smoking.  Western News. Retrieved from stories/2012 /August/research_finds_egg_yolks_almost_as_bad_as_smoking.html

3. CBC News.  (2012, August 14).  Egg yolks almost as dangerous as smoking, researcher says.  Retrieved from

4. Healy, M.  (2012, August 14).  No yolk: eating the whole egg as dangerous as smoking?  Los Angeles Times.  Retrieved from

5. NHS Choice.  (2012, August 15).  Eating egg yolks as ‘bad as smoking’. news/2012/08august/Pages/Eating-egg-yolks-as-bad-as-smoking.aspx

6. Djousse, L. and Gaziano, J.M.  (2008).  Egg Consumption and Risk of Heart Failure in the Physicians’ Health Study.  Circulation, 117, 512-516.

7. Hu, F.B., Stampfer, M.J., Rimm, E.B., Manson, J.E., Ascherio, A., Colditz, G.A., Rosner, B.A., Spiegelman, D., Speizer, F.E., Sacks, F.M., Hennekens, C.H. and Willett, W.C.  (1999).  A prospective study of egg consumption and risk of cardiovascular disease in men and women.  JAMA, 281(15), 1387-1394.


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