Eggs: Are they the healthiest food on the planet, as some say, or cholesterol-laden harbingers of cardiovascular doom?
The study, conducted by a team of more than a dozen researchers, looked at six different populations from 1985 to 2016 comprising a total of nearly 30,000 people.
They found that each additional 300 milligrams (mg) of cholesterol consumed daily increased a person’s risk for developing cardiovascular disease by 17 percent and an 18 percent higher risk for death from any cause.
A large egg contains around 186 mg of cholesterol. Researchers found that eating three to four eggs weekly was associated with a 6 percent higher risk of developing cardiovascular disease and an 8 percent higher risk of death from any cause during the study period.
So that’s it for eggs, right? Not quite.
First, it’s important to understand the arc of this ongoing debate about the relative impact cholesterol can have on a person’s diet.
The researchers note that part of the driving force behind this large and rigorous study was the U.S. government’s own conflicting information regarding cholesterol.
The Department of Health and Human Services’
However, the scientific report that accompanies those guidelines state that “cholesterol is not a nutrient of concern for overconsumption.”
To try to get to the root of this question, researchers studied large, ethnically and economically diverse groups of people for a longer range of time — up to 31 years of follow-up — unlike many previous studies and meta-analyses of existing research.
“It’s critically important to emphasize that demonstrating the effect of a single food on health is extremely complex,” Alice H. Lichtenstein, DSc, senior scientist and director of the Cardiovascular Nutrition Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston, told Healthline.
Lichtenstein, who’s also an American Heart Association (AHA) volunteer expert, added, “In this study — which is the most comprehensive study we have to date on this subject — the authors meticulously accounted for multiple potentially confounding factors.”
But while the study is a high-quality observational study, it’s still just an observational one. Meaning it’s hard to isolate the causes of egg consumption specifically.
For instance, researchers weren’t able to assess the long-term eating habits of study participants, study co-author Norrina Allen, PhD, associate professor of preventive medicine in the division of epidemiology at Northwestern University, said in a press release.
“We have one snapshot of what their eating pattern looked like,” she said. “But we think they represent an estimate of a person’s dietary intake. Still, people may have changed their diet, and we can’t account for that.”
The reason this topic tends to center around eggs is because, with the potential exception of the high levels of cholesterol in their yolks, eggs are extremely healthy.
Chicken eggs, in particular, are great sources of vitamins A, B-2, selenium, B-12, and folate. They’re also a great source of protein and antioxidants like lutein.
They’re even full of those brain and heart-healthy omega-3 fatty acids.
In fact, even with this study, the problem may not be eggs as much as it may be about other foods Americans tend to eat alongside them, Lichtenstein told Healthline.
“Given the subjects studied were living in the U.S., these results suggest that some of the effect may have been due to common dietary companions of eggs: bacon and sausage,” she said.
“[For instance] there was no significant relationship of eggs or cholesterol in individuals having normal blood cholesterol levels, and in some cases, older adults. The more important thing to remember is the overall dietary picture. Dietary cholesterol is just one piece of the puzzle.”
At the end of the day, the study may provide a better understanding of cholesterol’s part in our diet as well as eggs in particular, without moving the needle much.
The AHA and American College of Cardiology’s own 2019 guidelines recommend moderation in cholesterol intake, stating that “a diet containing reduced amounts of cholesterol and sodium can be beneficial to decrease ASCVD [atherosclerotic cardiovascular disease] risk.”
But that recommendation was classified as a moderate-strength recommendation with only moderate-quality evidence to back it up.
In other words, moderation is key.
“The take-home message is really about cholesterol, which happens to be high in eggs and specifically yolks,” Allen said. “As part of a healthy diet, people need to consume lower amounts of cholesterol. People who consume less cholesterol have a lower risk of heart disease.”