Even with thirty years of accumulated research showing that dietary cholesterol has only a small effect on plasma cholesterol levels, and that dietary cholesterol has little relationship to heart disease incidence, the dietary cholesterol and egg restrictions have become a staple of American dietary folklore easily incorporated into our fat-phobic, cholesterol-phobic life-style. But now that all seems to be changing and the consensus based on opinion is slowly giving way to an avalanche of research data showing that eggs are not the serious health concern they have been portrayed to be. Over the years eggs have literally become the icon for high cholesterol, both dietary and plasma, and it has taken considerable research efforts to prove that they do not belong in the "bad food group." But oh how the health promotion groups hate to have to say that just maybe the over emphasis on dietary cholesterol and egg restrictions for the past three decades was not really justified!

Eggs and Heart Disease Risk
The April 21st issue of the Journal of the American Medical Association (JAMA1999;281:1387-1394) [1] reports a study by Hu and colleagues from the Harvard School of Public Health which found no relationship between egg consumption and cardiovascular disease in a population of over 117,000 nurses and health professionals followed for eight to fourteen years. There was no difference in heart disease relative risk between those who consumed less than one egg a week and those who ate more than one egg a day. The investigators followed 80,082 women for 14 years and 37,851 men for 8 years and looked at the incidence of nonfatal myocardial infarction, fatal coronary heart disease and stroke as related to daily egg consumption determined by food frequency questionnaires. As shown in the figure, weekly egg consumption was unrelated to the relative risk of coronary heart disease in either the men or the women. Similar data were obtained for stroke relative risk.

Interestingly, the investigators also found no significant increase in relative risk of coronary disease in a small subset of the study group, who consumed two or more eggs a day relative to those who never consumed eggs (multivariate relative risk for women was 0.76 and for men 1.10). The authors did find that for diabetic subjects higher egg consumption was related to increased risk of coronary heart disease.

The authors concluded that "These findings suggest that consumption of up to 1 egg per day is unlikely to have substantial overall impact on the risk of CHD or stroke among healthy men and women." It would be easy at this point to argue that this is only a single study, albeit in a very large population, and no single report should determine the national nutrition policy regarding eggs and health. Fair enough argument except that this report is only one of a long list of recent studies showing that egg consumption, and dietary cholesterol intakes, are unrelated to either high plasma cholesterol levels or coronary heart disease incidence. The Harvard investigators have also reported that dietary cholesterol was not a significant factor in coronary heart disease risk in either the Nurses' Health Study [2] or the Health Professionals Follow-Up Study [3]. Similar findings of a non-significant relationship between dietary cholesterol and coronary heart disease risk have been reported from the Lipid Research Clinics Follow-Up Study [4], the Framingham Heart Study [5], and the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study [6]. Data from the Multiple Risk Factor Intervention Trial (MRFIT) [7] actually reported an inverse relationship between dietary cholesterol intakes and plasma cholesterol levels at baseline as well as an inverse relationship between egg consumption and plasma cholesterol levels. Over the years a number of investigators have reported a null relationship between egg consumption and plasma lipid levels as well as between egg intake and coronary heart disease incidence [8-10]. The report by Hu et al. [1] represents the largest epidemiologic study to directly relate egg consumption and coronary heart disease risk and its findings are consistent with a considerable body of existing literature. This is not a case of a single, isolated, inconsistent study providing an aberrant finding; this is a case of consistency and uniformity of results: as leading to a single conclusion: egg consumption is not related to coronary heart disease incidence.

These data are consistent with a number of other observations as well. Analysis of the relationship between per capita egg consumption and cardiovascular mortality rates for 24 countries indicates a negative relations. Three of the highest egg consuming countries in the world are Japan, Spain and France; countries which also have the lowest rates of cardiovascular mortality of any of the world's industrialized countries. The consistency of the data showing that the cholesterol in eggs is not related to coronary heart disease risk should at some point in time raise questions regarding the need for specific numerical restrictions of egg consumption by the general public ("no more than 3 to 4 whole eggs a week"). The evidence clearly shows that "an egg a day is okay" and unrelated to heart disease risk.

No Easy Vindication
A spokesperson for the American Heart Association (AHA) stated, "Egg consumption is associated with eating foods high in saturated fat such as bacon, red meat and whole milk. Most people eat two eggs, rather than one egg in a serving - a single meal that contains double the amount of suggested dietary cholesterol." [Complete version available at AHA News Releases.] I guess eggs are to blame for the company they keep hanging around those high saturated fat foods. Does this mean that if people who eat those high saturated fat foods don't eat eggs they'll not be tempted to eat them or that if people who are now avoiding those high saturated fat food started eating eggs their prudent diets would be ruined? And with this logic shouldn't we also restrict the consumption of peas to assure that the public doesn't put butter on them? I guess if eggs aren't the plasma cholesterol raising problem we think they are then at least guilt by association is one way to maintain a rather outdated, scientifically unsubstantiated restriction on their consumption.

And what about the over consumption with all those people eating two eggs a day? The data from the Harvard study did not find that this was a document able health concern, and per capita consumption data certainly argues against it becoming a population wide problem for the public. The peak of U.S. egg consumption was in 1945 with a per capita intake of 405 eggs per person per year. That equates to 7.8 eggs per week or 1.1 eggs per day. Today's intake is 244 eggs per person per year or 4.7 eggs per week, 0.7 eggs per day. And what seems to be lost in the spokesperson's comment is that the 300 mg cholesterol per day recommendation should be considered as an average value considered over a number of days or a week [11]. Whether a consumer chooses to eat their 7+ eggs a week one a day or a couple every few days really shouldn't matter to the AHA, unless, of course, one needs to find arguments for protecting that decision to restrict eggs in the diet made over 25 years ago.

Another spokesperson was quoted as saying that "The American Heart Association and other responsible public health associations won't change their guidelines of 3-4 eggs per week." It is amazing that highly qualified scientists would dismiss the findings of a major research report on the day of its publication and conclude that the results will have no effect on the nutritional policy of the organization. No evaluation, no deliberation, no discussion, no incorporation of these data into the existing body of knowledge on the question; only a terse dismissal because the findings disagree with preconceived opinions and biases. This is not a very reasonable way to formulate public nutrition policy or the most open-minded scientific approach for evaluating new research findings. Does this mean that once nutritional policies are set they are solidified to the extent that there can be no adjustments or corrections based on science? Maybe it is time for those groups who think the science supports their opinions to put their science to the test: lets have a real debate of the question with all sides providing documented evidence in support of their recommendations.

Where did the 300 mg per day cholesterol number come from? What is the evidence that eggs increase the risk of heart disease and why are 3 to 4 eggs per week the limit? Let's move away from the opinions of the 70s and get with the science of the 90s. We should be able to do better in our efforts to guide the public towards healthful, nutritious diets using science, not the consensus of a small group based on their uniformity of opinions.

REFERENCES
1. Hu FB, Stampfer MJ, Rimm EB, et al. A prospective study of egg consumption and risk of cardiovascular disease in men and women. JAMA 1999;281:1387-1394.
2. Hu FB, Stampfer MJ, Manson JE, et al. Dietary fat intake and the risk of coronary heart disease in women. N Engl J Med 1997;337:1491-1499.
3. Ascherio A, Rimm EB, Giovannucci EL, Spiegelman D, Stampfer M, Willett WC. Dietary fat and risk of coronary heart disease in men: Cohort follow up study in the United States. Bmj 1996;313:84-90.
4. Esrey KL, Joseph L, Grover SA. Relationship between dietary intake and coronary heart disease mortality: Lipid research clinics prevalence follow-up study. J Clin Epidemiol 1996;49:211-216.
5. Millen BE, Franz MM, Quatromoni PA, et al. Diet and plasma lipids in women .1. Macronutrients and plasma total and low-density lipoprotein cholesterol in women: The Framingham nutrition studies. J Clin Epidemiol 1996;49:657-663.
6. Pietinen P, Ascherio A, Korhonen P, et al. Intake of fatty acids and risk of coronary heart disease in a cohort of Finnish men - The alpha-tocopherol, beta-carotene cancer prevention study. Am J Epidemiol 1997;145:876-887.
7. Tillotson JL, Bartsch GE, Gorder D, Grandits GA, Stamler J. Food group and nutrient intakes at baseline in the Multiple Risk Factor Intervention Trial. Am J Clin Nutr 1997;65(1) Suppl:228S-257S.
8. Dawber TR, Nickerson RJ, Brand FN, Pool J. Eggs, serum cholesterol, and coronary heart disease. Am J Clin Nutr 1982;36:617-25.
9. Gramenzi A, Gentile A, Fasoli M, Negri E, Parazzini F, La Vecchia C. Association between certain foods and risk of acute myocardial infarction in women. BMJ 1990;300:771-3.
10. Fraser GE. Diet and coronary heart disease: beyond dietary fats and low-density- lipoprotein cholesterol. Am J Clin Nutr 1994;59:1117S-1123S.
11. Krauss RM, Deckelbaum RJ, Ernst N, et al. Dietary guidelines for healthy American adults - A statement for health professionals from the Nutrition Committee, American Heart Association. Circulation 1996;94:1795-1800.