A single large egg packs 6.3 grams of protein, 5.3 grams of fat, and roughly 77 calories. But the real story is what else comes along for the ride: a surprisingly wide range of vitamins, minerals, and other compounds that are hard to find in such concentrated form anywhere else in your diet.
Protein That Your Body Actually Uses
Eggs are one of the highest-quality protein sources available. Using a scoring system called DIAAS, which measures how well your body can digest and use the amino acids in a food, cooked eggs earn an “excellent” rating (100 or above) for anyone older than six months. That puts them at the top tier alongside other animal proteins, meaning nearly all the protein you eat in an egg gets put to work by your body.
Cooking matters here. Your body absorbs 90 to 97% of the protein in a boiled or gently cooked egg. Raw eggs are significantly less efficient, and they contain a protein called avidin that blocks absorption of biotin, a B vitamin. Cooking deactivates avidin, so you get both better protein uptake and access to biotin in a single step.
More than half of an egg’s protein is in the white, with the rest in the yolk. If you’re eating only whites to cut calories, you’re still getting a solid protein source, but you’re leaving a lot of other nutrients behind.
Where the Vitamins Are
The yolk is where eggs really distinguish themselves. All of the egg’s vitamin A, vitamin D, vitamin E, and vitamin K are concentrated in the yolk, along with most of its B6, B12, folic acid, and pantothenic acid. The white contributes mainly niacin and riboflavin.
Two vitamins stand out as especially valuable:
- Vitamin D: Eggs are one of the few natural food sources of vitamin D, providing about 82 IU per 100 grams. That’s a meaningful contribution given how many people fall short on this nutrient, particularly in winter months or with limited sun exposure.
- Vitamin B12: A 100-gram serving of whole egg provides roughly 0.89 micrograms of B12, which supports nerve function and red blood cell production. For people who eat limited amounts of meat or fish, eggs can help fill this gap.
Choline: The Nutrient Most People Miss
One large hard-boiled egg delivers 147 milligrams of choline, about 27% of the daily value for adults. Choline is essential for brain function, liver health, and cell membrane integrity, yet most Americans don’t get enough of it. Eggs are the single most concentrated common food source of choline, which is one reason nutrition guidelines consistently include them as a nutrient-dense food.
This is particularly relevant during pregnancy, when choline demands increase to support fetal brain development. Two eggs a day would cover more than half the recommended intake.
Minerals Worth Noting
Eggs provide a useful range of minerals, again with the yolk doing most of the heavy lifting. The yolk contains more calcium, copper, iron, manganese, phosphorus, selenium, and zinc than the white. The white, for its part, contributes most of the egg’s magnesium, potassium, and sodium.
Selenium deserves a closer look. Hen eggs contain about 51 micrograms of selenium per 100 grams, and a single egg can supply roughly 16 to 48% of the recommended daily allowance depending on the type of egg. Selenium acts as an antioxidant at the cellular level and plays a role in thyroid function, making eggs a practical way to maintain adequate levels without supplements.
The Fat in Eggs
The 5.3 grams of fat in a large egg are entirely in the yolk. About a third of that fat is saturated, with the rest split between monounsaturated and polyunsaturated fats. A standard egg contains a small amount of omega-3 fatty acids, but not enough to be a meaningful source on its own.
Omega-3 enriched eggs, produced by feeding hens a diet supplemented with fish oil or flaxseed, change that picture. These specialty eggs can contain 116 to 207 milligrams of DHA per 100 grams, along with smaller amounts of EPA. DHA is the omega-3 fatty acid most associated with brain and eye health, making enriched eggs a reasonable option for people who don’t eat much fish.
What About Cholesterol?
A large egg contains about 186 milligrams of dietary cholesterol, all of it in the yolk. This used to be a reason people avoided eggs, but the current Dietary Guidelines for Americans (2020-2025) no longer set a specific daily cholesterol cap. The guidelines do recommend keeping dietary cholesterol “as low as possible without compromising the nutritional adequacy of the diet,” and they list eggs as a nutrient-dense food alongside vegetables, fruits, whole grains, and seafood.
For most people, dietary cholesterol has a smaller effect on blood cholesterol than saturated fat does. The saturated fat in an egg (about 1.6 grams) is modest compared to many other animal foods, which is part of why eggs maintained their place in dietary recommendations even as the conversation around cholesterol evolved.
Yolk vs. White: A Quick Comparison
The yolk makes up about 34% of the egg’s liquid weight but carries 55 of its roughly 78 calories. Here’s how the nutrients split:
- Yolk: All the fat, nearly half the protein, all fat-soluble vitamins (A, D, E, K), most B vitamins, choline, and most minerals including iron and selenium.
- White: More than half the protein, most of the niacin and riboflavin, most of the potassium and magnesium, and about 17 calories with zero fat.
If you’re eating eggs purely for protein and calories are a concern, whites make sense. But if you’re eating eggs for overall nutrition, the yolk is where the bulk of the value sits. Discarding it means losing the choline, the vitamin D, the iron, and the selenium that make eggs stand apart from other protein sources.