Middle-aged men who ate seven or more eggs a week had a higher risk of earlier death, US researchers say.

Men with diabetes who ate any eggs at all raised their risk of death during a 20-year period studied, according to the study published in the American Journal of Clinical Nutrition.

The study adds to an ever-growing body of evidence, much of it contradictory, about how safe eggs are to eat.

It did not examine what it is about the eggs that might affect the risk of death.

Men without diabetes could eat up to six eggs a week with no extra risk of death, Dr Luc Djousse and Dr J. Michael Gaziano of Brigham and Women's Hospital and Harvard Medical School found.

"Whereas egg consumption of up to six eggs a week was not associated with the risk of all-cause mortality, consumption of (seven or more) eggs a week was associated with a 23 per cent greater risk of death," they wrote.

"However, among male physicians with diabetes, any egg consumption is associated with a greater risk of all-cause mortality, and there was suggestive evidence for a greater risk of MI (heart attack) and stroke."

They urged more study in the general population. Eggs are rich in cholesterol, which in high amounts can clog arteries and raise the risk of heart attack and stroke.

One expert on nutrition and heart disease said the study suggests middle-aged men, at least, should watch how many eggs they eat.

"More egg on our faces? It's really hard to say at this point, but it still seems, if you're a middle-aged male physician and enjoy eggs more than once a day, that having some of the egg left on your face may be better than having it go down your gullet," said Dr Robert Eckel of the University of Colorado and a former president of the American Heart Association.

"But, remember: eggs are like all other foods - they are neither 'good' nor 'bad,' and they can be part of an overall heart-healthy diet," Eckel wrote in a commentary.

The Harvard team studied 21,327 men taking part in the much larger Physicians' Health Study, which has been watching doctors since 1981 who have agreed to report regularly on their health and lifestyle habits.

Over 20 years, 1550 of the men had heart attacks, 1342 had strokes, and more than 5000 died.

"Egg consumption was not associated with (heart attack) or stroke," the researchers wrote.

But the men who ate seven eggs a week or more were 23 per cent more likely to have died during the 20-year period.

Diabetic men who ate any eggs at all were twice as likely to die in the 20 years.

Men who ate the most eggs also were older, fatter, ate more vegetables but less breakfast cereal, and were more likely to drink alcohol, smoke and less likely to exercise - all factors that can affect the risk of heart attack and death.

Reuters