Middle-aged men who ate seven or more eggs a week had a higher risk of earlier death, U.S. researchers reported on Wednesday.

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 about the eggs 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 percent 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.

Neither 'good' nor 'bad'
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.

More likely to drink, smoke
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, 1,550 of the men had heart attacks, 1,342 had strokes, and more than 5,000 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 percent 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.

美國研究人員周三報告說，一周吃七個或者更多雞蛋的中年男子有更高的提早死亡的風險。

根據刊登在美國臨床營養學雜志上的這份研究報告，在長達20年的研究期間里，患糖尿病的男性吃任何雞蛋都無例外地增加了自己的死亡風險。

這份研究報告加入到不斷增加的關于如何安全吃雞蛋的證據材料中，其中很大一部分是矛盾的。但是它沒有研究雞蛋怎么可能影響死亡風險。

布里格姆與婦女醫院和哈佛醫學院的醫生Luc Djousse和醫生 J. Michael Gaziano發現，無糖尿病的男子可以一周吃六個雞蛋而沒有額外的死亡風險。

“一周的雞蛋消費量達到6個雞蛋與所有原因死亡率的風險沒有關聯，而一周消費（ 7個或更多）雞蛋則伴隨有 23％ 以上的死亡風險，”他們寫道。

“然而，在患糖尿病得男性醫生中，任何雞蛋消費都與所有原因死亡率的更大風險相關聯，并且有更大的心肌梗塞（心臟病發作）和中風風險的術前診斷證據。”

他們呼吁在一般人群中進行更多的研究。

雞蛋既不‘好'，也不‘壞'

雞蛋富含膽固醇，而高量的膽固醇可能阻塞動脈并且增加心臟病發作和中風的風險。

一位營養學與心臟病方面的專家說，這項研究表明，中年男性至少應該注意他們吃多少個雞蛋。

“更多的雞蛋在我們面前？在這一點上實在很難說，但是它仍然似乎是，如果你是一位中年男性醫師，并且一天享用雞蛋一次以上，則讓這個雞蛋留一些在你的面前可能比讓它下到你的食道里要好一些，”科羅拉多大學的博士和美國心臟協會的前會長Robert Eckel說。

“但是，請記住：雞蛋像所有其它的食品一樣——它們既不是‘好’的 ，也不是‘壞’的 ，而且它們可能是整個有益心臟健康的飲食的一部分，”Eckel在一篇評論中寫道。

可能是更多地飲酒、吸煙

哈佛大學的專家小組對參加了大得多的醫師健康研究的21,327名男子進行了研究，他們自1981年以來看醫生，同意定期匯報他們的健康情況和生活習慣。

20多年過去， 1,550名男子曾經心臟病發作， 1,342名曾經中風，并且有5,000 多人死亡。

“雞蛋消費量與（心臟病發作）或中風無明顯關聯，”研究人員寫道。

但是，一周吃掉7個或者更多雞蛋的男子是23％ 更多的可能在20年期限內死亡。
吃任何蛋類的糖尿病男子是兩倍地可能會在20年內死去。

男人吃最多的雞蛋并且更老一些、更胖一些，吃較多的蔬菜但是較少的早餐谷類食品，以及可能更多地飲酒、吸煙并且可能較少地運動——所有這些都是可能影響心臟病發作和死亡風險的因素。