Industry-sponsored egg supplement

I am very disappointed that a previous issue of Canadian Family Physician (CFP) was coupled with a supplement of the International Journal of Clinical Practice.1 The supplement was supported by an “educational grant” from the Egg Farmers of Canada, the Canadian marketing agency for eggs (many of us are familiar with their “get cracking” advertising campaign), which represents a billion dollar Canadian industry.2

With this type of endorsement, CFP has become an advertising tool, using the sophisticated marketing technique of a medical journal as a vehicle for industry promotion. As a result, it is Canadians who will suffer confusion and ill health as they are misled into thinking that eggs are a harmless food.

The supplement was called “A Review of the Harvard Egg Study.”1 It reviewed the egg consumption of a subpopulation in the Nurses’ Health Study from the 1980s and 1990s, which was published under the title “A Prospective Study of Egg Consumption and Risk of Cardiovascular Disease in Men and Women” in the Journal of the American Medical Association (JAMA) in 1999.3 The study’s authors were affiliated with the Harvard School of Public Health; hence, it has been dubbed the “Harvard Egg Study,” a savvy title from this industry-supported publication.

The review states that “consumption of up to seven eggs per week is congruent with a healthy diet.”1 It further espouses that cholesterol intake is not likely a significant cause of cardiovascular disease, and questions the strength of data regarding cholesterol from the Framingham Heart Study.1

Buried in the back of this thick supplemental issue is an article entitled “Dietary Cholesterol and Other Nutritional Considerations in People with Diabetes,”4 which reports that subgroup analysis of the “Harvard Egg Study” population showed egg consumption as indeed harmful to patients with diabetes, even at the low levels described in the study. Somehow, the word egg was left out of the title of an article demonstrating eggs’ deleterious effects in those with diabetes— another interesting choice by the editors of this supplement supported by the egg marketing agency.

This is not the first advertisement by the Egg Farmers of Canada. The April 2009 issue of CFP had a full-page ad referring to the same study. This ad quoted negative findings in people without diabetes but made no mention of the harm in people with diabetes.

The JAMA study evaluated egg consumption at very low levels—only 1 to 7 eggs per week—and still managed to discover negative effects in people with diabetes. It would also be relevant to know the effects of higher egg consumption. Owing to lack of power, higher doses of egg consumption were excluded from the final results. Further, it might be unlikely that eggs alone are a contributor to heart disease and cancers. The more interesting question would be about animal-based foods in combination, compared with a healthy plant-based diet. Here is a quote from the final JAMA study, which refers to the null results among the non-diabetic study group: One potential alternative explanation for the null finding is that background dietary cholesterol may be so high in the usual Western diet that adding somewhat more has little further effect on blood cholesterol. In a randomized trial, Sacks et al found that adding 1 egg per day to the usual diet of 17 lactovegetarians whose habitual cholesterol intake was very low (97 mg/d) signifcantly increased [low-density lipoprotein] cholesterol level by 12%. In our analyses, differences in non-egg cholesterol intake did not appear to be an explanation for the null association between egg consumption and risk of [coronary artery disease]. However, we cannot exclude the possibility that egg consumption may increase the risk among participants with very low background cholesterol intake. Also, we have limited power to examine the effect of high egg consumption (eg, 2 eggs per day).3

There are other medical and nutritional studies published about eggs. Why would CFP promote only this particular industry-sponsored review, which quotes the original article but does not express its limitations? A more lucid presentation of the original article would be better. I have listed some other articles and studies on eggs and nutrition in the reference list below.5–10 These include the famous study by Ornish et al published in JAMA 1998,9 and a publication of the Food and Agricultural Organization of the United Nations10 regarding the effects of terrestrial animal agriculture (the document is massive, but the executive summary is worth a read). I believe that the Ornish et al9 study is the first human study that shows coronary artery plaques can be reversed, and a plant-based diet is a cornerstone of this clinical trial. It is time that nutrition, health, and issues such as the environment are considered in concert.

In the future, I hope that CFP will take such factors into consideration regarding industry-sponsored publications and nutritional information. I hope that an equal emphasis will be given to the many studies from reputable journals that discuss the benefits of plant-based diets.

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