Do eggs increase risk for heart attacks
Do Eggs Increase Risk for Heart Attacks?

March 20, 2014
 by Gabe Mirkin, MD

After years of bad publicity, the jury is still out
on eggs. Nobody really knows whether they increase
risk for heart attacks. Most of the research papers
show that those who have normal blood pressure and
cholesterol and are not diabetic are not at
increased risk for heart attacks when they eat up
to one egg a day (JAMA, 1999; 281:1387-94; Curr
Opin Clin Nutr Metab Care, 2006; 9:8-12).
 
However, there are dissenting studies:
 * Canadians who ate three egg yolks a week
suffered increased rate of heart attacks
(Atherosclerosis, August 2012).
 * Australian Aborigines who ate more than two eggs
per week had almost triple the rate of heart
attacks compared to those who did not eat eggs
(Preventive Medicine 2007;44(2):135-42).
 * People in the United Kingdom who consumed six or
more eggs per week had an almost triple increase in
rate of death from heart attacks (Heart 1997;78(5):450-5).
 
Is Lecithin the Culprit?
 Recent research from the Cleveland Clinic shows
that eggs may increase heart attack risk by a
mechanism that has nothing to do with cholesterol.
Lecithin, found in large amounts in eggs yolks,
appears to increase heart attack risk. Bacteria in
the intestines convert lecithin to TMAO, a chemical
that has been shown repeatedly to damage the inner
linings of arteries to start plaques forming in
arteries and increase heart attack risk (NEJM,
April 25, 2013;368:1575-1584). The same bacteria
convert carnitine in meat to TMAO that also
increases heart attack risk. Some intestinal
bacteria can convert lecithin, carnitine, choline
and creatinine to TMAO. 

Egg Yolks and Cholesterol
 Egg yolks are one of the most concentrated food
sources of cholesterol. Eating more than one egg a
day can raise blood cholesterol levels a very small
amount for some people. However, most of the recent
research shows that dietary cholesterol is probably
not a significant risk factor for heart attacks.
More than 80 percent of the cholesterol in your
body is made by your liver. When you eat less
cholesterol, your liver makes more. When you eat
more cholesterol, your liver makes less.
 
Limit Eggs if You Have High Cholesterol or High
Blood Pressure or are Diabetic
 Eggs may increase risk for heart attacks for those
who are diabetic or have high cholesterol or high
blood pressure. There is data to show that eating
more than one egg a day increases heart failure
risk for these people (Circulation, 2008; 117:512-6).
 
The Framingham Heart Study found no association
between eating eggs and heart attacks. The Health
Professionals Follow-up Study and the Nurses’
Health Study found no association between an egg a
day and heart attacks, but excluded people who
smoked, had high cholesterol, heart attacks,
diabetes, or cancer (The Journal of the American
Medical Association 1999;281(15):1387-94).
Excluding these risk factors removes the people
most likely to suffer heart attacks from eating
eggs. However, male physicians who ate more than
six eggs per week did have an increased rate of
heart attacks (The American Journal of Clinical
Nutrition 2008;87(4):964-9). So did Englishmen
consuming more than six eggs per week (Heart
1997;78(5):450-5).
 
My Recommendations:
 Eating three eggs a week appears to have no effect
on risk for heart attacks. I recommend no more than
one egg per day, but we do not really know what
amount is safe. Almost everyone needs to limit the
foods that are often eaten with eggs: sausage,
bacon, fried potatoes, cheese, bakery products and
so forth.