Bengaluru: If you eat more than half an egg daily, a new US study has bad news for you.

The study of about 30,000 US participants over a period of nearly two decades indicated that excessive egg consumption — beyond 300 mg — caused a 17 per cent increased risk of heart attack and an 18 per cent increased risk of early death.

When the readings were calculated for a daily impact, the study showed that each additional egg per day (600 mg) raised the heart risk by 6 per cent and death risk by 8 per cent.

The study conducted by researchers at Northwestern University, Illinois — Victor W. Zhong, Linda Van Horn and Marilyn C. Cornelis — was published on 15 March in Journal of the American Medical Association.

Cholesterol and heart disease

While the relationship between cholesterol and heart disease is still not fully understood, Dr. Robert H. Eckel, a professor of medicine at the University of Colorado who co-authored an editorial that came with the study, said that the new study was much more comprehensive than previous works on the subject.

“There’s enough data to make a strong statement that eggs and overall dietary cholesterol in-take remain important in affecting the risk of cardiovascular disease, and more so the risk of all-cause mortality,” he wrote.

The study examined the relationship between eggs, cholesterol consumption, and cardio-vascular problems among Americans. The country hasn’t seen much change in the past several decades in the amount of cholesterol consumed — about 300 mg a day.

Heart disease and stroke are the biggest killers worldwide, claiming a combined 15.2 million deaths in 2016, according to World Health Organisation.

Risks

The study found that people who work out more and are generally fitter than the rest of the population seemed to consume more eggs for their protein and fat content requirements.

But the results indicated that even for people on healthy diets or those with a healthy body, the effects of eggs and cholesterol in raising their risk for heart disease was consistent.

The researchers stressed the benefit of amino acids and minerals, but advise people to consume less yolk anyway.

Egg yolks are one of the richest sources of dietary cholesterol among foods eaten regularly. On an average, each egg yolk contains 180 mg of dietary cholesterol.

Effects of eggs

A number of dietary recommendations for how many eggs to consume in a day seem to contradict one another. The standard accepted practice is to keep dietary cholesterol at less than 300 mg a day, but the more recent American guidelines seem to measure cholesterol consumption in a week, not a day. This is primarily because of the lack of clear and precise understanding of the effect of fat.

This is true for scientific studies as well, with several reaching contradictory conclusions.

The authors of the latest Northwestern study were able to isolate the effects of just eggs rather than overall consumption of cholesterol, and deduced that with an addition of just half an egg a day, a person’s risk significantly increases.

These findings are independent of body shape, size, exercise, daily activity, and overall health and fitness levels.

The study, though, does come with its own limitations.

For one, all subjects self-reported what they ate. The researchers also used a single kind of measure for the constitution of an egg and also a fixed template for dietary habits.

Also read: Why are so many people getting a meat allergy?

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