The new results were published online on Friday in Journal of the American Medical Association.
Researchers at Northwestern University's Feinberg School of Medicine and elsewhere gathered results from six previous studies and analyzed data on nearly 30,000 American adults, such as self-reported daily food intake. On average, participants were followed on average by 17 years.
The researchers have calculated that those who ate 300 milligrams of cholesterol daily – approx. 1½ eggs – was 17 percent more likely to develop heart disease than if who did not eat eggs.
The researchers based their conclusions on what the participants said they ate at the beginning of each study. They accounted for high blood pressure, smoking, obesity and other features that could contribute to heart problems. Risks were found with eggs and cholesterol in general; A separate analysis was not performed for each cholesterol-rich food.
Dr. Bruce Lee from Johns Hopkins University said that nutrition studies are often weak because they rely on people to remember what they were eating.
"We know that dietary recall can be terrible," Lee said. The new study only offers observation data, but does not show that eggs and cholesterol cause heart disease and death, says Lee, who was not involved in the research.
Senior author Norrina Allen, a preventative medicine specialist, noted that the study lacks information on whether participants ate eggs cooked, poached, fried or encrypted in butter, which she said could affect health risks.
"Some people think I can eat as many eggs as I want, but the results suggest moderation is a better approach," she said.
Eggs are a leading source of dietary cholesterol, which was once thought to be highly related to blood cholesterol and heart disease. Older studies suggest that the link led to nutritional guidelines almost a decade ago, which recommended consuming no more than 300 milligrams of cholesterol daily; an egg contains approx. 186 milligrams.
Recent research questioned that the relationship, finding that saturated fats contributes more to unhealthy levels of blood cholesterol, can lead to heart problems.
The latest US government nutritional guidelines, from 2015, removed the strict daily cholesterol limit. While eating as little cholesterol as possible, the recommendations recommend that eggs can still be part of a healthy diet as a good protein source along with lean meat, poultry, beans and nuts. Nutritionists say the new study is unlikely to change that advice.
Dr. Frank Hu from Harvard University noted that most previous studies have shown that eating a few eggs a week is not associated with heart disease risks in generally healthy people.
"I do not think this study would change overall healthy guidelines for eating", highlighting fruits, vegetables, whole grains, nuts and beans, and limiting processed meat and sugar, Hu said. Eggs, a breakfast pin for many, may be included, but other options should also be considered, "like whole grain cabbage with nut butter, fresh fruit and yogurt," Hu said.
Dr. Rosalind Coleman, a professor of nutrition and pediatrics at the University of North Carolina, offered broader advice.
"The main message to the public is not to choose a single type of food as" bad "or" good ", but to evaluate your overall diet in terms of variety and quantity.
"I'm sorry if it seems like a boring recommendation," she added, but for most people, the main dietary advice "should be to maintain a healthy weight, exercise and get enough sleep".