Eating egg yolks is as 'bad as smoking' in speeding up coronary heart disease
Cripes! I am a dead man! I am in my 70th year and I have been eating two eggs for breakfast most days for many years! Though maybe my resting BP of 130/80 gives some hope. Not bad for an old guy, I think.
Seriously, though, the effects found below are very small in absolute magnitude (c. 9% more plaque) and the subject population was not representative. See the abstract appended
Scientists have unscrambled the truth about eggs - eating the yolk is almost as bad as smoking for people at risk of heart disease.
The problem lies in an increased risk of the hardening of the arteries, known as atherosclerosis. It is a disorder of the arteries where plaques, aggravated by cholesterol, form on the inner arterial wall.
As a key component of a traditional English breakfast, the new findings may not put off egg lovers.
But Dr David Spence revealed eating the yolk of an egg is about two-thirds as bad as smoking when it comes to the build up of plaques.
Having surveyed 1,231 men and women, Dr Spence, of the University of Western Ontario, London, Canada, linked the findings to stroke and heart attack risk factors. Plaque rupture is the usual cause of most heart attacks and many strokes.
The study involved patients, with an average age of 61.5, attending vascular prevention clinics in Ontario. Ultrasound was used to establish a measurement of total plaque area and questionnaires were filled out regarding the patients’ lifestyles.
The research found carotid plaque area increased in line with age after 40, but increased above the average rise after years of regular smoking and egg yolk consumption. The study also found those eating at least three yolks a week had significantly more plaque area than those who ate up to two yolks per week.
Dr Spence, 67, who is also a neurology professor, said: 'The mantra ‘eggs can be part of a healthy diet for healthy people’ has confused the issue. 'High cholesterol intake increases the risk of cardiovascular events, and egg yolks have a very high cholesterol content.
'The study shows that, with age, plaque builds up gradually in the arteries and egg yolks make it build up faster.'
Dr Spence added that the effects were independent of sex, cholesterol, blood pressure, smoking, body mass index and diabetes.
He said that while he feels more research should be done, he stressed the regular consumption of egg yolk should be avoided by persons at risk of cardiovascular disease.
The research has been published online in the journal Atherosclerosis.
Increasingly the potential harm from high cholesterol intake, and specifically from egg yolks, is considered insignificant. We therefore assessed total plaque area (TPA) in patients attending Canadian vascular prevention clinics to determine if the atherosclerosis burden, as a marker of arterial damage, was related to egg intake. To provide perspective on the magnitude of the effect, we also analysed the effect of smoking (pack-years).
Consecutive patients attending vascular prevention clinics at University Hospital had baseline measurement of TPA by duplex ultrasound, and filled out questionnaires regarding their lifestyle and medications, including pack-years of smoking, and the number of egg yolks consumed per week times the number of years consumed (egg-yolk years).
Data were available in 1262 patients; mean (SD) age was 61.5 (14.8) years; 47% were women. Carotid plaque area increased linearly with age after age 40, but increased exponentially with pack-years of smoking and with egg-yolk years. Plaque area in patients consuming less than 2 eggs per week (n = 388) was 125 ± 129 mm2, versus 132 ± 142 mm2 in those consuming 3 or more eggs per week (n = 603); (p < 0.0001 after adjustment for age). In multiple regression, egg-yolk years remained significant after adjusting for coronary risk factors.
Our findings suggest that regular consumption of egg yolk should be avoided by persons at risk of cardiovascular disease. This hypothesis should be tested in a prospective study with more detailed information about diet, and other possible confounders such as exercise and waist circumference.