Are Egg Yolks Bad for You?

Are those myths about egg whites being "healthier" than egg yolks all that they're cracked up to be? A customer emailed Life Extension's health science experts wanting to know exactly that: "I've always ordered egg white omelets because I heard they are healthier for my heart. But my daughter told me the yolk has more health benefits than the white and that it's been disproven that yolks raise cholesterol. What's the truth?"

We are all-in on a yummy egg white omelet, especially if filled with some fresh spinach and mushrooms! It's a high-protein, low-fat treat, after all. And certainly, no one likes when their child tries to one-up them on nutritional knowledge. But when you see today's Millennials eating open-faced avocado toast with a soft-cooked yolk oozing tantalizingly on top, you do have to wonder if they're on to something…or, if you should be worrying about their cholesterol levels!

To settle this matter once and for all, we spoke with Life Extension's Education Specialist Dr. Crystal Gossard, DCN, CNS, LDN, who is co-host of the podcast Live Foreverish. And it turns out the answer is a bit more "scrambled" than "over-easy." Here's what she shared.

What are egg yolks, anyway?

Dr. Gossard: The yolk is the yellow part that's in the center of an egg. We don't always like to think about where the animal foods we eat come from, but to get technical, with a bird egg, the yolk is what provides nutrients to a developing chick before it hatches. (Don't worry, the eggs that make it to your breakfast plate aren't fertilized!). There are few sources of nutrition in our diet that are as rich as an egg yolk.

What nutrients do egg yolks contain?

Egg yolks contain many important nutrients which offer our bodies terrific health benefits. This food is a good source of:

• Protein
• Amino acids, including tryptophan
• Vitamin A (an important antioxidant)
• B vitamins, including folate, riboflavin, vitamin B6 and B12
• Iron
• Choline

Egg yolks are also a great way to get enough lutein, zeaxanthin and choline in your diet—crucial for eye health and a must for anyone concerned about their risk for macular degeneration. And again, you can get these benefits by eating one egg a day, which offers 139 mg of choline, or you can take a choline supplement.

Another question I get a lot is whether eggs contain vitamin D. The answer is yes! In fact, eggs are one of the few good food sources of "the sunshine vitamin." (Other food sources of vitamin D include fatty fish, meat and dairy.)

Egg yolk nutrition facts: According to the USDA, the nutritional content for the yolk of a large egg is 54.7 calories, 2.7 grams of protein, 4.5 grams of fat, 1.7 grams of saturated fat, and less than a gram of carbohydrates.

Are egg yolks bad for you?

Dr. Gossard: The short answer is no. The yolk is one of the most nutrient-dense components of the egg since it is where vitamins, minerals, and essential fats are concentrated. On a gram-to-gram basis, the yolk has more protein than the white.

However, just because something is good for you doesn't mean you should eat as much of it as possible! Eating unlimited egg yolks isn't something I would recommend. There are conflicting studies about how egg yolks may or may not influence cholesterol levels, because they do contain saturated fat, and at this point in time, I suggest consuming eggs in moderation, no more than one per day. Many people like to mix an egg white with a full egg for a filling breakfast that's lighter on dietary cholesterol. (If that's not filling enough for you, I would throw in extra egg whites and some veggies before I would add extra egg yolks.)

Also, I do want to caution about going overboard when it comes to egg white substitutions, which many of us did during the "fat-free" craze of the 1990s. I hate to state the obvious, but if you're using whole eggs in a recipe for baked goods, the yolk is probably the healthiest ingredient you're cracking into that mixing bowl! You can separate eggs to remove the yolk if you'd like, but just note that the flour, sugar and butter are the ingredients that are why we consider baked goods a "treat" and not something to eat daily. Your best bet is to just make the cake according to the instructions (which usually means using the whole egg, at least one of them) and enjoy it in moderation.

What makes egg yolks orange?

The yolk color can range from pale yellow to a deep orange that's almost red in color. We've all been taught to "eat the rainbow" when it comes to our fruits and veggies—but this actually isn't the case with egg yolks because the color has very little to do with nutritional value.

What chickens are fed influences the color of the egg yolk, and when the birds are given red peppers, the yolk takes on that reddish hue. (Note that, as the name implies, the egg white is always white!)

Q. Are eggs high in cholesterol?

Dr. Gossard: Yes, eggs are one of the main dietary sources of cholesterol. There is more cholesterol in an egg than in beef! But do eggs actually raise blood cholesterol levels, and in turn, lead to heart disease? This is highly debated, with many reliable studies showing conflicting outcomes.

Q. Are eggs bad for your heart?

Dr. Gossard: Again, this is very much up for debate! In 2020, a large Harvard analysis of 215,000 people found that one egg per day was not associated with increased risk of heart disease (i.e., did not raise blood cholesterol).

But a more recent 2021 study, which happens to be the largest group study on the topic, reported something different. The researchers examined the egg consumption and cholesterol in relation to death from different causes in over 500,000 people. The participants completed a food frequency questionnaire at the beginning of the analysis and were followed for an average of 16 years.

The researchers discovered that the people who ate whole eggs versus egg whites had a higher rate of mortality and heart disease and every additional half-egg participants ate per day was associated with a 7% higher risk of premature death. This data gives me pause and is why I don't think people should be eating eggs as freely as they would, say, fruits and vegetables.

Q. How many egg yolks should I eat in a day?

Dr. Gossard: Given what research tells us right, your safest bet is to consume eggs in moderation, meaning no more than one per day. That means if you want two or three eggs in a meal, maybe the following day, you don't have any eggs.

And, if you want to be cautious, boil your egg, cut it in half, and remove half of the egg yolk. This way, you are still reaping the benefit of the nutrition components found in the yolk, such as lutein which is good for vision, as well as folate and vitamin A.

And if you want to be extra cautious or because you are at high risk, just stick to egg whites! It can get messy to separate an egg (especially if a little egg shell falls into the liquid) and many people worry about wasting the yolk, so buying liquid egg whites is always an acceptable option.

What kind of eggs should I buy?

Dr. Gossard: You will see many choices in the supermarket, such as "cage-free" eggs or "free-range" eggs. These terms refer to the living conditions of the hens before the eggs are taken and sold. All eggs of the same size will have similar nutritional content and health benefits, with pasture-raised providing the most nutrition.

What can I use instead of eggs in my baking?

Dr. Gossard: I have an easy recipe for a flax seed egg replacement. For each egg you want to replace, simply combine one tablespoon of ground flax seed with three tablespoons of water, then let sit for five minutes. Flax seeds are a great source of essential fatty acids and guard against cardiovascular disease, making them the perfect substitute for those concerned about the cholesterol in eggs. And they'll make many dessert recipes instantly vegan!

References

• Drouin-Chartier, Jean-Philippe, et al. "Egg consumption and risk of cardiovascular disease: Three large prospective US cohort studies, systematic review, and updated meta-analysis." BMJ. March 2020. https://www.bmj.com/content/368/bmj.m513
• Huizen, Jennifer. "All you need to know about egg yolk." Medical News Today. November 2019. https://www.medicalnewstoday.com/articles/320445
• Spence, David J., et al. "Dietary cholesterol and egg yolks: Not for patients at risk of vascular disease." Can J Cardiol. November 2010. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2989358/
• Zhuang, Pan, et al. "Egg and cholesterol consumption and mortality from cardiovascular and different causes in the United States: A population-based cohort study." PLoS Med. February 2021. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7872242/
• "Comparing egg white and egg yolk." Egg Info. https://www.egginfo.co.uk/egg-nutrition-and-health/egg-nutrition-information/white-and-yolk/compare