The Reason Eggs Are Controversial (And Why You Should Eat Them)
Scientists may disagree about eggs, but most evidence is in favor of eating them
Trying to keep up with eggs’ nutritional reputation (they’re good for you, they’re bad for you, they’re good for you again) is whiplash-inducing.
The constant debate centers almost exclusively around the high cholesterol content found in egg yolks. One medium-sized yolk contains 186 mg of cholesterol — 62% of the recommended daily intake. The yolk also happens to be where most of an egg’s nutrients are located. Vitamins A, D, E, and K are found here, as are minerals like iron, zinc, magnesium, potassium, and calcium. Depending on the chicken’s feed, omega-3 fatty acids can also sometimes be found in the egg yolk.
Yes, eggs are high in cholesterol. That much is indisputable. What is frequently disputed is whether dietary cholesterol (the type of cholesterol found in food) affects blood cholesterol (specifically LDL levels, aka “bad” cholesterol). This is the point where research spirals.
In a 2019 study, Dr. Neal Barnard, the president of the Physicians Committee for Responsible Medicine, reviewed 211 studies dating back from to 1950s up to the most recent data available, all of which looked at how eggs affect blood cholesterol. Barnard found that close to 90% of the studies report some kind of spike in cholesterol levels among people who consume eggs. Barnard also found that the root of the ongoing confusion seems to stem from the fact that a large percentage of recent studies on eggs and cholesterol are funded directly by the egg industry. This portion of research, Barnard says, has a tendency to downplay the findings.
“In the 1950s and ’60s, there was no egg industry funding at all for cholesterol research,” Barnard says. “All of the funding was done by noninterested bodies like governmental bodies and health foundations. Then, starting in the 1970s and 1980s and really ramping up into the current century, you see the egg industry jumping in in a very big way to try to fund research studies to show that eggs are innocuous. In recent years, 60% of the studies on eggs have been funded by the egg industry itself.”
Barnard explains that one common tactic used to minimize the role dietary cholesterol might play on blood cholesterol is to observe a small number of people so that the results can’t be considered definitive. “If you have a really small number of participants, you’ll get results that may not be statistically significant, which means you can show the effect, but you can’t rule out that it could have been a chance finding,” he explains.
The egg industry’s influence in these studies has succeeded in causing confusion not only for the public but among policymakers as well. In 2015, when the Dietary Guideline Committee issued its new set of dietary guidelines (a resource used heavily by federal agencies and officials in public health, healthcare, and education), they initially reported that recent evidence showed dietary cholesterol had no appreciable effect on blood cholesterol levels.
It’s not like we can observe someone in a cage for three months to see what effect food has on their body.
“That made headlines everywhere,” Barnard says. “It is clearly untrue that dietary cholesterol doesn’t affect blood cholesterol. It does.” In the end, when the government issued the final version of the guidelines, they ultimately rejected the committee’s recommendation on this point. Instead, the final version suggests “individuals should eat as little dietary cholesterol as possible.”
In Barnard’s opinion, that translates to eating none at all. “All animal products have cholesterol while plant products never do,” he says. “If you don’t eat animal products, you don’t consume cholesterol. The closer you get to avoiding eggs the better off you are.”
For Lisa Sasson, a clinical professor of nutrition and food studies at NYU Steinhardt, the answer isn’t quite so cut and dried. Instead of making a sweeping recommendation to fully eliminate all cholesterol from a healthy diet, Sasson wants the health community to place more of an emphasis on developing a better understanding of the unique and widely varied ways individuals’ blood cholesterol levels can be affected by dietary cholesterol.
“We need to observe a person’s whole diet and lifestyle instead of just looking at specific nutrients,” she says. “We have to understand that cardiovascular disease [the primary health concern linked to high cholesterol] is multifactorial. It’s not about just one food. It’s about looking at dietary patterns, but also risk factors like smoking, physical activity, and genetics.”
She adds that whether the study is industry-funded or not, achieving conclusive findings from food studies is notoriously difficult. “It’s not like we can observe someone in a cage for three months to see what effect food has on their body. Even when participants keep a food diary, you don’t really know that it’s completely true,” she says.
Overall, Sasson says she still considers eggs to be a healthy food choice when eaten in moderation, ideally a few a week at most. This way you can reap the health benefits of egg yolks while also keeping any potential cholesterol risk at bay.
“There’s nothing wrong with eating eggs; the yolk is very healthy, but I would never give anyone the green light to eat a few every day. I encourage people to use one full egg and three whites. The white has no cholesterol, it’s very low in calories, and with the one yolk in there you can still have a nice, fluffy egg omelet.”
That’s still a lot of healthy egg consumption. “Low to moderate consumption of three or four eggs a week doesn’t appear to have a major effect on blood cholesterol unless the person has high cholesterol or Type 2 diabetes,” Dr. Frank B. Hu, chairman of nutrition and epidemiology at the Harvard T.H. Chan School of Public Health told the New York Times in 2019.
“We should be eating real food—food that is as least processed as possible,” she says. “Ultimately, nutrition is a science that is relatively new. As we learn more, a lot of it is taken out of context. The bottom line is that as we come to new conclusions, we have to really be sure we’re questioning who is funding the studies.” At least Sasson and Barnard can both agree on that.