Once demonised as bad for the heart, eggs have been repositioned as a health food in recent years as researchers have found that not only are they good for hearts, but can even help you to lose weight.

But last week Canadian researchers published findings that could crack eggs’ nutritious reputation.

In the study of 1,200 subjects with an average age of 61, it was suggested that build-up of carotid plaque, a waxy substance that clogs blood vessels and is linked to cardiovascular disease, was greater in people who ate at least two eggs per week.

The researchers specifically blamed egg yolks for this effect.

Britons eat nearly 30 million eggs a day. Should we curtail our egg habit to protect our hearts?

Are eggs bad for your cholesterol levels?

The latest Canadian research ‘goes against the grain of current scientific thinking’, says Helen Bond, of the British Dietetic Association.

A few years ago, Bruce Griffin, professor of nutritional metabolism at the University of Surrey, analysed 30 egg studies carried out over 30 years and found eggs ‘have no clinically significant impact’ on cholesterol levels.

Can eggs protect your heart?

In fact, a study in the American Journal of Clinical Nutrition found eggs helped to maintain healthy blood pressure levels, says Helen Bond.

And last year, scientists at the University of Alberta discovered egg yolks contain two important amino acids, tryptophan and tyrosine, and that two raw egg yolks have almost twice as many antioxidants as an apple.

Frying or boiling reduced antioxidant levels by about half.

Eggs are packed with nutrition:

Thanks to changes in chicken feed, eggs today are healthier than those produced 30 years ago.

Modern eggs contain 70 per cent more vitamin D and double the amount of selenium.

Levels of these are low in the UK diet, and linked to an increased risk of cancer, cardiovascular disease and infertility. Each egg yolk also provides 13 essential nutrients.

How many eggs can I eat?

The Department of Health now says we can eat as many eggs as we like, as long as they form part of a healthy, balanced diet. There is no upper limit, says Bond, unless you have inherited high cholesterol.

Of the Canadian study, she says that carotid plaque rises anyway with age after 40.

And the researchers didn’t take into account lifestyle factors such as exercise and diet.

Are eggs fattening?

In the Department of Health analysis it was found that eggs contain around 20 per cent less fat, 13 per cent fewer calories and 10 per cent less cholesterol than 30 years ago.

In one study, overweight women had eggs or a bagel for breakfast. The egg eaters consumed fewer calories in the following 24 hours.

‘Scientists put the positive effects down to the satiating effects of egg protein,’ says Bond.