THURSDAY, April 10, 2008 (HealthDay News) -- A new study suggests that consuming more than six eggs a week seems to raise the risk of dying from all causes.
And diabetics seem to face an even higher mortality risk, according to the study that was limited to men.
"The more eggs diabetic men consumed, the more they increased their risk for death," said study lead author Dr. Luc Djousse, an associate epidemiologist at Brigham and Women's Hospital and an assistant professor at Harvard Medical School in Boston.
Djousse and his team analyzed egg consumption and mortality data among more than 21,000 men who had participated in a Physician's Health Study that explored heart disease and cancer prevention among American male doctors.
Participants ranged in age from 40 to 86. Over an average of 20 years, all the doctors completed annual written questionnaires on daily egg consumption, stroke and heart attack incidence, diabetes status, cholesterol levels, alcohol and smoking habits, and general dietary information.
On average, the physicians were found to have consumed one egg a week -- a rate the study authors termed "relatively low."
Overall, egg consumption wasn't found to be associated with heart attack or stroke risk. And consumption of up to six eggs a week also wasn't found to be associated with a higher risk of death from all causes. But eating seven or more eggs a week among healthy study participants was linked to a 23 percent higher risk of death.
Even more striking was the finding that mortality risk was much higher among those doctors with diabetes. Consuming seven or more eggs a week doubled their risk of death from all causes, compared with diabetic doctors who ate just one egg each week.
The findings were published in the April issue of The American Journal of Clinical Nutrition.
Heart disease is the leading cause of death in the United States, and elevated LDL ("bad") cholesterol is a prime risk factor for cardiovascular trouble. And while eggs are rich in cholesterol -- and circulating cholesterol is related to the risk of cardiovascular disease -- the relationship between dietary cholesterol and blood cholesterol is complex. Some studies have suggested that dietary cholesterol doesn't affect blood cholesterol levels in many people, but it may in other individuals, such as those with diabetes, the researchers noted.
A single egg contains about 200 milligrams of cholesterol -- just 100 milligrams shy of the daily limit advocated for those at risk for heart disease, the researchers added.
On the other hand, eggs are a source of minerals, folate, B vitamins, protein and monounsaturated fats -- all of which have the potential to lower overall risk.
To explain the finding on diabetic men, the researchers theorized that diabetics might somehow convert dietary cholesterol more readily into blood cholesterol than people without diabetes.
"We need additional data to confirm these findings, so it's kind of premature to advise against egg consumption until we have more information," Djousse said.
Donald McNamara, executive director of the Washington, D.C.-based Egg Nutrition Center, said that while diabetics need to carefully assess all aspects of their diet, "no one food exists in isolation."
"And when we look at all the other studies that have been published, they show that easily an egg a day can fit into a healthy diet with no change in heart-disease risk for the average person and those with diabetes," McNamara added. "Eggs also provide some very important nutrients in terms of high quality protein and choline, which we know is insufficient in the diet today. So, you have to balance out the nutritional contribution of eggs in the diet relative to this kind of a study, which presents a very unique finding which has not been presented anywhere else, and has a lot of variables included that we don't know enough about."
In an accompanying editorial published in the journal, Dr. Robert H. Eckel, a professor of physiology and biophysics at the University of Colorado and co-chair of both the Cardiometabolic Health Congress and the Committee on Cardiovascular and Metabolic Diseases, echoed some of McNamara's comments and called for more research to validate the study findings.
"Eggs are like all other foods -- they are neither 'good' nor 'bad', and they can be part of an overall heart-healthy diet," Eckel said. But he suggested that those wary of the high cholesterol content in whole eggs might want to skip yolks in favor of egg whites, which are ripe with protein, riboflavin and selenium.
And Lona Sandon, a registered dietician and assistant professor of clinical nutrition at the University of Texas Southwestern Medical Center at Dallas, said that "the white part of the egg is the gold standard for protein."
"It contains all the essential immunoacids that your muscle needs for building," she said. "It's better than beef even. And it's one of the cheapest sources of protein as well. There are some good things in the yolk as well. But for someone who has had their cholesterol measured and found to have high LDL, the American Heart Association and the American Dietetic Association say watch your egg consumption, and try not to consume more than two yolks per week."
For additional information on nutrition and diabetes, visit the American Diabetes Association.