Do Eggs Cause Heart Attacks and Premature Death?
At the beginning of my 24-year medical career, egg consumption was condemned as a cause of heart attacks. Heart attacks can kill. How did eggs kill? It was thought to be related to the cholesterol content - 200 mg per egg - leading to higher serum cholesterol levels, which clogged arteries (atherosclerosis), leading to heart attacks.
Ten years ago the pendulum began to swing the other direction: Egg consumption didn’t seem to matter much, if at all.
The evidence is usually collected in observational, epidemiologic studies of large groups of people. The groups are analyzed in terms of overall health, food intake (e.g., how many eggs per week), healthy lifestyle factors, etc. Egg consumption of the group is broken down, for example, into those who never eat eggs, eat 1-4 eggs per week, eat 5-10 per week, or over 10 eggs weekly. A group is followed and re-analyzed over 10-20 years and rates various diseases and causes of death are recorded. Researchers don’t follow just 25 people like this over time. You need thousands of participants to find statistically significant differences.
The debate about eggs was re-opened (although never really closed) by the publication in April, 2008, of an article in The American Journal of Clinical Nutrition. Scientists of the Physicians’ Health Study suggest that consumption of seven or more eggs weekly is associated with significantly increased risk, over 20 years, of all-cause mortality. Interestingly, this level of consumption did not cause heart attacks or strokes. Study participants, by the way, were 21,327 Harvard-educated male physicians. 5,169 deaths occurred during 20 years of follow-up. If you’re not a Harvard-educated male physician, the study results may not apply to you.
When physicians with diabetes - type 2’s mostly, I assume - were analyzed separately, consumption of even less than seven eggs per week was associated with higher all-cause mortality.
Several other observational studies looking at this same issue have found no association between egg consumption and cardiovascular disease, heart attacks, and all-cause mortality.
Bottom line? If you worry about egg consumption, limit to 7 or less per week. If you have type 2 diabetes, limit to 4 or less per week.
Remember, all the cholesterol is in the yolk. Try making an omelet using the whites only. But in our lifetimes you will never see an observational study looking at egg white consumption and mortality rates.
I’m still not convinced egg consumption is worth losing sleep over. “More studies are needed…”
Steve Parker, M.D., author of The Advanced Mediterranean Diet: Lose Weight, Feel Better, Live Longer www.AdvancedMediterraneanDiet.com
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October 9th, 2008 at 9:34 am
Hey Doc.
Good post.
How do you feel about excessive egg white consumption? The last part of your post suggests that you believe that egg whites can and should be consumed freely, but to what extent?
I currently eat 4 egg whites (and veggies) for breakfast each day and often include egg whites in other foods that I make. While they are nearly perfect nutrition content-wise (tons of protein, few calories), I worry about consuming so much of one food - especially an animal product.
What are your thoughts?
October 9th, 2008 at 12:33 pm
Hi, Amy.
Who could be in favor of “excessive egg white consumption”? I know you’re really asking what level of consumption would be excessive. That’s hard to say. It would be at the point where other needed nutrients were crowded out of your diet. I doubt that 4-6 egg whites a day would cause problems. [I assume you cook them.]
-Steve