Eggs are not healthy, says a report that scrambles a controversy

Eggs are not as healthy as they are cracked up to be, says a report in the Canadian Journal of Cardiology.

First we were told to eat very few eggs because the yoke contains too much cholesterol. Then we were told that eggs aren’t really bad for our health, and that it’s safe to an egg every day. Now the authors of a report in an academic journal claim that eggs put people at greater risk of heart attacks and strokes than a pair of infamous “dietary disasters,” the KFC Double Down burger and Hardee’s Monster Thickburger.

     What’s going on here?

      It’s all very confusing.

     When I was released from hospital following my cardiac arrest in 1989, I was advised to eat no more than two eggs a week. On our very recent semi-annual checkups, our family doctor told Joan and I that the two-eggs a week advice is no longer valid, that it’s safe to eat one or two eggs a day. Eight days later, the news media carried stories of a report in the Canadian Journal of Cardiology claiming that eggs are risky for your health.

       The two-eggs-per week rule for people with heart trouble was based on a 1970 recommendation from the American Heart Association. The AHA continues to recommend that, “People with heart disease should limit egg yokes to two per week.” For healthy people, it recommends less than 300 mg of dietary cholesterol per day—enough for one egg per day if other sources of cholesterol are carefully limited.

     An eight-year study of 117,000 men and women on “egg consumption and risk of cardiovascular disease” published in the Journal of the American Medical Association in 1999 concluded “that consumption of up to one egg per day is unlikely to have substantial overall impact on the risk of CHD [coronary heart disease] among healthy men and women.” Other case studies have also concluded that moderate egg consumption offers little or no heart risk to healthy people, despite the very high concentration of cholesterol.

      Why? It seems to be another case of good fat, bad fat. Only 27 percent of the fat-like cholesterol in an egg is the bad saturated fat containing the bad cholesterol, the LDL (low-density lipoprotein); the rest is the healthier unsaturated fat. Aside from the cholesterol question, eggs are loaded with healthy nutrition: an excellent source of protein and a solid source of 14 essential nutrients, say Alberta Egg Producers.

     Dietitian Clara Rosenbloom, in an article in the web site of the Heart and Stroke Foundation of Canada, writes that the early studies on which the two-eggs per rule was based were in error, and summarizes the subsequent change in thinking:

     “These early studies included foods that were rich in both cholesterol and saturated fat (such as butter), so scientists incorrectly believed that cholesterol was the main culprit. When researchers recently re-evaluated the data, they learned that diets high in saturated or trans fat—not dietary cholesterol—are mostly responsible for increases in blood cholesterol levels… Because one large egg contains just 1.6 grams of saturated fat and no trans fat, scientists have recently concluded that the earlier link between eggs and blood cholesterol was largely exaggerated. However, foods that contain high levels of dietary cholesterol, such as egg yokes, may have a small effect on cholesterol levels in people diagnosed with high blood cholesterol or type 2 diabetes.”

     Yet some studies apparently suggest that dietary cholesterol might adversely affect the ratio of total HDL and LDL. Another study suggests that eggs can increase the risk of type 2 diabetes http://www.biowizard.com/pmabstract.php?pmid=19017774. The U.S. Department of Health in a 1991 study cited in the Canadian Journal of Cardiology, recommends a daily limit of not 300 mg of dietary cholesterol, as suggested by the American Heart Association, but 200 mg, and not just for those with coronary disease or diabetes, but also for healthy people.

     The authors of the Canadian Journal of Cardiology report—David Spence, a stroke prevention expert at the Robarts Research Centre in London, and nutrition and cholesterol researchers David Jenkins of Toronto and Jean Davignon of Montreal—say eggs are far from as safe as widely believed.

     There is “widespread misconception” among both the public and physicians “that consumption of dietary cholesterol and egg yolks is harmless,” they write. “Dietary cholesterol increases the susceptibility of low-density lipoprotein [LDL] to oxidation, increases  postprandial lipemia and potentaties the adverse effect of dietary saturated fat. Dietary cholesterol, including egg yolk, is harmful to the arteries.”

      In layman’s language, the three researchers claim that egg yokes can:

     •Increase the oxidation of LDL, the “bad” cholesterol in your blood. LDL oxidation can result in inflammation of the arteries, increasing the risk of heart attack or stroke.

      •Cause a greater boost in the saturated fat in your blood that normally follows a meal (postprandial) for a period of time.

      •Increase the potential of saturated fat to clog your arteries.

     The authors suggest that studies indicating healthy people are not harmed by eating eggs, might be in error. “Although some studies showed no harm from consumption of eggs in healthy people, this outcome may have been due to lack of power to detect clinically relevant increases in a low-risk population.”

     The authors take issue with studies that have been cited to support claims that eggs are safe to eat, particular that 1999 JAMA (Journal of the American Medical Association) study and a 2007 study (“Regular egg consumption does not increase the risk of stroke and cardiovascular disease”) in the Medical Science Monitor. Egg proponents who cite these studies, say the authors, fail to mention that participants who became diabetic during the studies had increased cardiovascular risk from eating eggs. In the case of the JAMA study “consumption of one egg a day doubled their risk as compared with less than one egg a week.”

      The comparison of eggs with the “dietary disasters” of the KFC Double Down burger and Hardee’s Monster Thickburger came from comments by David Spence as quoted in news reports. Depending on the size of the egg, Spence and his colleagues say that a yoke contains 215 to 275 mg of cholesterol. That’s more than the 200 mg per day recommended by the U.S. Department of the Health, more than the 150 mg in a  KFC Double Down, and more than the 210 mg in the Monster Thickburger. Aside from the cholesterol, however, the two burgers are also dangerously high in salt and saturated fat. Eggs have less salt, and no fat.

     The Egg Farmers of Canada quickly issued a release disputing the attack on  l’oeuf. “With obesity increasing in North America at an alarming rate, medical professionals should be encouraging the consumption of nutrient-dense, low-calorie foods, such as eggs,” declared Bonnie Cohen, an Egg Farmers’ dietitian. The Egg Farmers say that a large Canadian egg has only 195 mg of cholesterol, rather than the 215 to 270 mg cited by Spence and his colleagues. “If the researchers get this number wrong, we must question the accuracy of the complete report,” said Laurent Souligny, chair of the Egg Farmers.

Bottom line

     Whether eggs are harmful or helpful to your health, this much is certain: they won’t improve your cholesterol levels, especially the LDL that causes clogging in the arteries and heart trouble. Does this concern you?  It concerns me. Because I’m a heart attack survivor, I’m said to be at high risk of more heart trouble. My LDL level is well within the recommended range for those deemed to be at low or moderate risk, but too high for those said to be at high risk. Dr. Marie Cescon, our family physician, wants me to lower my LDL to a recommended level.

     I’ll continue to eat eggs—but just the whites, not the yokes. The whites have virtually all the nutrition of whole eggs without the cholesterol. They have no fat and are a very good source of protein, although somewhat high in salt  (NutritionData.com.) We will again eat frozen, packaged, coloured egg whites, as we did more than two decades ago. “Things are seldom what them seem, skim milk masquerades as cream,” wrote librettist W.S. Gilbert. And egg white masquerade very well as real scambled eggs.

     In my next blog, I’ll talk about how I plan to tackle the challenge of lowering my LDL, by exercise and fine-tuning an already healthy diet. And why I need to lower that LDL without the aid of medication.

     TAGS: Eggs. Cholesterol. Canadian Journal of Cardiology. American Heart Association Journal of the American Medical Associiation. LDL (low-density lipoprotein). Heart and Stroke Foundation of Canada. Egg Farmers of Canada. U.S. Department of Health.