The Definitive Egg Story: What To Know About Cholesterol In Eggs

For a while, it felt as if we'd gotten over our paranoia about eggs. Studies emerged showing that dietary intake of cholesterol from eggs was not as closely tied to high blood cholesterol (a risk factor for heart disease) as once thought. The daily dietary cholesterol cap of 300 mg was removed from our national dietary guidelines. And many doctors and nutritionists stopped preaching egg-white omelets and started embracing whole eggs, citing their beneficial levels of vitamin D, choline, vitamin K2, and other nutrients that are often hard to find elsewhere.

Then came a 2019 JAMA1 study1 in which researchers concluded that the dietary cholesterol in eggs is associated with a higher risk of heart disease and early death. The study, which analyzed data from six different observational studies involving 30,000 U.S. adults, found that for each extra half-egg eaten per day, the risk of cardiovascular disease (CVD) increased 6 percent, and risk of early death went up 8 percent.

Countless news outlets reiterated the conclusion, stoking the egg debate once again. But soon after the initial "eggs are bad again" news frenzy, the counter-opinions began trickling in, with a number of respected health experts and journalists calling the study and its findings into question.

Longtime New York Times health and nutrition reporter Anahad O’Connor referred to it as "bad science," and nutritional researcher Zoe Harcombe, Ph.D., posted a 10-point Twitter rant about "things wrong with the egg study," highlighting that the truly concerning thing here was not eggs and their cholesterol content, but rather, how findings of nutritional epidemiological studies are often taken as gospel when, in reality, they have their limitations. 

When I asked Ethan Weiss, M.D., cardiologist and associate professor at U.C. San Francisco's Cardiovascular Research Institute, if this study's findings were enough to consider revising our dietary guidelines to reinstate a cholesterol cap, his response was an emphatic no. He recalls that his response was "some sort of expletive-laced rant about how I can't believe we're having this conversation again."

The first problem with this study, Weiss says, is that it's observational. Nutritional epidemiology2, in which researchers observe and examine the eating habits and health outcomes of a population over time, has long been criticized for its inability to measure diet accurately, and for the tendency of these studies to yield conflicting results. Case in point: a 2020 study published in the American Journal of Clinical Nutrition3, which used similar methods of surveying participants about their eating patterns, found the opposite results: eating more eggs was not associated with higher cholesterol, more cardiovascular events, or a greater risk of mortality.

"Plenty of people much smarter than me have written eloquently about the idea that nutritional epidemiology is just kind of garbage," he says. "It's basically a tarot card reading; you can see whatever you want in these results. But it gets a lot of attention, and as long as people keep reacting to it the way they have been, we're going to keep seeing it." 

The core problem with nutritional epidemiology, Dr. Weiss says, is that people tend to only accurately recall about 50 percent of what they eat. And even when the data is good, there are many confounding factors that it's difficult to identify how one component of a person's diet is truly affecting their health. "What goes along with eggs? Well, maybe people who eat eggs are also eating lots of bread or potatoes or bacon. It's really hard to untangle what the actual problem is," says Dr. Weiss. Meaning, it's possible that other dietary or lifestyle factors are responsible for the increased risk.

John Ioannidis, M.D., DSc, professor of medicine and health research and policy at Stanford University School of Medicine, has spoken and written extensively4 on the flaws of observational nutrition studies, suggesting that funds be redirected to fewer better-designed, randomized trials. "These studies need to be largely abandoned," he said in a Stanford Medicine interview. "Recall biases, in which study participants remember something incorrectly, can be severe...in addition, dietary intake of a single nutrient probably has small or even tiny effects on major health outcomes."

A huge shortcoming of this particular study: The dietary questionnaire was completed at only one point in time over the course of the 17-year study—and this limited data was the basis of their conclusions. "To draw any firm causative conclusions from this type of data is impossible," says Laura Schoenfeld, R.D., a registered dietitian trained in functional nutrition.

It's also important to note that even if the data compiled for this study was completely accurate, the increased health risk of eating eggs was slim. "The risk increase was only 6 to 8 percent, which is still such an insignificant increase compared to the true risk factors for heart disease," says Schoenfeld. To put that in perspective, research shows smoking cigarettes increases the risk of coronary heart disease 70-200%5 (depending on smoking frequency). "We need to be focused on the true heart disease risk factors and not be splitting hairs about the pros and cons of consuming nutritious real foods like eggs."

And other experts agree: "These findings shouldn't necessarily scare anyone away from eggs, given that the increase in risk associated with eating eggs was really minimal," says neuroscientist and integrative nutritionist Lisa Mosconi, Ph.D.

When did this whole egg-cholesterol controversy start in the first place? It dates back to 19686, the year the American Heart Association (AHA) issued a recommendation that people consume no more than 300 mg of cholesterol per day (eggs have about 200 mg each) and no more than three whole eggs per week (how they got to this number still remains a mystery6). After that, cholesterol-containing foods were widely considered the biggest dietary villain implicated in heart disease. "My dad's a cardiologist too, and when I was a kid, there was this rule in our house that we'd never eat eggs," Weiss says. "We'd have Egg Beaters, and we didn't eat shrimp or any foods rich in cholesterol."

This fear of cholesterol was reflected in our dietary guidelines for quite some time, with the recommendation for limiting cholesterol to 300 mg per day remaining intact until recently. But in 2015, the Dietary Guidelines Advisory Committee issued a report7 stating that "available evidence shows no appreciable relationship between consumption of dietary cholesterol and serum cholesterol." (More recent research shows that saturated and trans fats are more likely culprits8 of high cholesterol.) Shortly after, when the official U.S. Dietary Guidelines for Americans 2015-2020 were issued, they still emphasized minimizing cholesterol in the diet, but they did not include a recommended cholesterol cap. "It became clear that the intake of dietary cholesterol was not as tightly related to levels of blood cholesterol as people thought," says Dr. Weiss.

The amount of high-quality data needed to truly implicate dietary cholesterol (and, by default, eggs) in the development of heart disease simply wasn't there. And, most people agree, it still isn't. "I've covered nutrition for a long time and have noticed that the large number of studies looking at the link between dietary cholesterol and heart disease appears to be contradictory or at best mixed," says O'Connor. 

So, can we say eating an egg or two a day won't up your risk for heart disease? Absolutely not. But we can't say it will either. "This response is very variable and probably genetically driven," says Dr. Mosconi. "But only about 20 percent of the cholesterol we measure in blood comes from cholesterol in the diet. There is some evidence that other fats, especially trans-fat and saturated fat, raise cholesterol levels more than actual cholesterol does."

Even in studies that link eating eggs to CVD risk, it's small. Take this 2022 study which attributed a 6-9% increase in CVD related mortality risk to each additional egg eaten.

Many experts I spoke with agreed that, for most people, there's no reason to eliminate eggs from your diet or to let this study negatively color your opinion about them.

The fact is, eggs are an incredibly potent source of nutrients. In addition to being packed with protein, which can keep blood sugar levels stable throughout the day, egg yolks (where all the cholesterol is found), are truly a superfood and contain most of the vitamins and minerals our bodies need for good health, says Schoenfeld. A few standout nutrients: choline, which is critical for cognitive function and liver health (and fetal brain development); vitamin K2, an underappreciated vitamin that's actually protective against heart disease by preventing arterial calcification; and biotin, a nutrient well-known for supporting hair, nail, and skin health. All that said, the types of eggs you choose are also very important, so consider opting for pasture-raised varieties, which tend to be higher in omega-3 fatty acids and vitamins K2, E, and A.

"I really believe you need to look at the big picture of someone's health," says Jess Cording, R.D., registered dietitian and mbg Collective member. "Eggs definitely have a place in an overall nutrient-rich whole-foods-based diet. All of the foods we eat contribute all kinds of nutrients and compounds that can support overall health. Even if someone was eating the exact 'perfect' amount of eggs, that won't matter much if the rest of their diet is total crap."

Meaning, if you have pretty good dietary and lifestyle habits, eggs probably aren't something to worry about; and if you don't, well, it's probably not the eggs' fault that you're unhealthy.

But experts say the number of eggs you can safely consume per week will depend on a variety of genetic and lifestyle factors. Someone who is diabetic or a heavy smoker will have to take a different approach than a vegetarian with no family history of heart disease. To help you come to your own conclusion, we asked our experts about their personal egg-eating habits, or what they recommend to patients. Their responses ran the gamut, but there are some useful take-aways.

"I probably eat seven eggs a week without even thinking about it," Weiss says. "I don't think that remotely sets off anything; and for me, because I'm lean and in tune with my health, I could probably double that. If somebody wants to have an egg every day, go for it." For reference, the AHA says an egg a day19 can be part of a heart-healthy diet.

As for Schoenfeld: "My typical recommendations for general health is that people can consume an average of two to three eggs per day without any concern of excessive intake. I'm not really concerned about someone developing heart disease strictly from eating too many eggs, especially if the rest of their diet and lifestyle is generally heart-healthy." Integrative dietitian Ali Miller, R.D., agrees: "I personally consume 12 to 16 eggs per week for nutrient support and hormonal balance, as cholesterol is a precursor or building block of hormones."

Other experts, however, take a much more cautious approach. Dr. Mosconi errs somewhat on the side of caution, saying that while she considers eggs a great brain food, she wouldn't recommend more than three to four per week. "A couple of eggs here and there can't possibly harm you, whereas eating several eggs every single day might, depending on your genetics, your medical status, and your lifestyle, among other factors."

"The biggest risk factors for heart disease are smoking, uncontrolled high blood pressure, physical inactivity, obesity, uncontrolled diabetes, and uncontrolled stress and anger," says Schoenfeld. So making a point to eat a nutrient-dense, whole-foods-based diet (fiber-rich foods are especially good at lowering "bad" LDL cholesterol), manage your stress, and get plenty of physical activity can go a long way in cutting your risk. 

As mentioned above, trans fats and saturated fats are probably much more likely to raise cholesterol levels in the body than are sources of dietary cholesterol. Research20 also links added sugars to an increase in "bad" LDL cholesterol and reduction in "good" HDL cholesterol. So putting your energy toward reducing your intake of these, especially in the form of highly processed foods (which often contain all three), is probably the smarter route. 

You should also take a closer look at the numbers on your blood lipid panel test. "Arguably, the best blood-lipid-related marker of heart disease risk is the total-to-HDL cholesterol ratio, which ideally should be below 4 (3 to 4 is optimal)," says Schoenfeld. "Simply zeroing in on total cholesterol levels is not helpful when it comes to predicting a person's heart disease risk."

Most experts I spoke with said there are only a few reasons (beyond the obvious food allergies or sensitivities) that someone may need to eliminate all eggs from their diet.

People with diabetes or existing heart health issues may want to limit eggs, depending on how many other sources of cholesterol they eat. "I would strongly urge patients with pre-diabetes, diabetes, and heart disease to avoid all egg yolks," says cardiologist and mbg Collective member Joel Kahn, M.D.. His recommendations reflect some of the studies mentioned above, which have found an increased risk of heart disease with egg consumption, particularly among diabetic patients.

Eggs are a good source of protein and many essential vitamins. They contain significant cholesterol, and while we once thought this translated to higher blood cholesterol and heart disease risk, newer research suggests that’s not the case. Overall, research on eggs and cardiovascular disease remains mixed. But any one food is unlikely to make or break your health, there’s no need for healthy people to cut eggs out of an otherwise balanced diet. (Though it’s wise to pair eggs with foods low in cholesterol and saturated fat.) People with heart health concerns or diabetes may want to limit their egg intake per week or swap some whole eggs for egg whites. It’s always best to consult your doctor for advice on tailoring your diet to your specific health needs.

When you consider the entire body of research on eggs and heart health, and the fact that they contain many beneficial nutrients, most of our experts agree that high-quality eggs can be a good addition to an overall healthy diet—and that our fears are probably being unreasonably stoked by the 2019 egg study heard round the world.

However, exactly how many eggs you can eat per day is highly variable and there is no one-size-fits-all answer. While some people may not tolerate eggs, other people may benefit greatly from their nutrients. So you should always consider your personal health history and habits before ramping up your intake of any food, and pay attention to how they react in your individual body.