Nutrition of an Egg

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Which came first, the chicken or the egg? We know that chicken is an excellent source of lean protein, however, there have been mixed reviews on whether or not eggs are equally as nutritious. A chicken comes from an egg, so we would expect the answer to be obvious. But there is so much more to an egg than simply “pre-chicken.”

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Nutrition of the chicken egg

Let’s dive deep into eggs: what they’re made up of, their nutritional value, how to buy, and (of course) how to cook.

Anatomy of the egg

 We are all familiar with the shell of the egg: white or brown, tough to crack. Here is something you may not know. Egg shells are made primarily out of calcium carbonate and are covered in thousands of tiny pores, making it semipermeable to air and water. There are also two thin membranes within the shell that help to keep out bacteria and dust.

Anatomy of an egg diagram

Breaking through to the part that we eat, we have the albumen (or egg white), chalazae, and the yolk. There are four layers of alternating thick and thin albumen surrounding the yolk. These layers are made up of water and about 40 different proteins. The chalazae are two opaque ropes of egg white that suspend the yolk in the center of the egg. You can tell how fresh an egg is based on how prominent the chalazae are: the more prominent, the fresher they are. 

And now for the star of the egg: the yolk. The yolk is composed of some water, fat, and protein, as well as a host of vitamins and minerals (iron, vitamins A and D, phosphorus, calcium, etc.). If you look closely, there is a small white dot within the yolk that is the germinal disc (not shown in Image 1). The germinal disc is the small group of cells that may develop into a chick, and the yolk provides nutrients for that development (or for our bodies). But don’t worry! Commercially produced eggs are not fertile; eating them is not taking the life of a baby chicken.

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There are a few other features labeled in Image 1, however they are not relevant to the nutrition of an egg. One other factoid to note is that the color of the yolk depends on the breed and feed that a hen receives, and does not indicate its nutritious value.

Nutrition facts for eggs

A standard large egg contains the following nutritional content:

70 calories

0 grams of carbohydrates

5 grams of fat

6 grams of protein

With this profile, eggs are an excellent food to include in a nutritious diet. The protein in eggs is a complete protein, meaning that it contains all of the essential amino acids that the human body does not produce on its own. This means that eggs alone can do our bodies a lot of good, especially with muscle repair, growth, and function.

Some may be concerned about the fat in the yolk however, this fat is vital for the digestion of the fat-soluble vitamins also contained in the egg (i.e. vitamins D, E, A, and some others require fat in order to be absorbed and utilized by the body). 

And there is so much more!

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Eggs contain choline and lutein, two integral nutrients when it comes to brain development and cognition. Not only is this good news for expecting mothers and young children, but also for the rest of us! These nutrients can keep us sharp even as we age. Choline also plays a role in liver function, and lutein can help slow the progression of various age-related eye conditions. All of that combined with the benefits of the protein gives us strength of mind and body as we get older.

Even better, consuming eggs regularly has been seen to improve cardiometabolic health, as well as help with weight control. A few studies have shown that consuming eggs helped people with type II diabetes decrease their blood lipid (fat) and glucose (sugar) markers and promoted glycemic control. Others have shown that people with metabolic syndrome who consume eggs see positive changes in HDL cholesterol, insulin levels, and other aspects of their lipid profiles. All this to say, consuming eggs can make a difference for health status, especially when included with other healthy lifestyle changes.

One of my favorite benefits of eggs are all of the ways you can eat them! But before we dive into that, let’s talk more about how to buy eggs…

Types of eggs

Cage Free, Free Range, Organic, Oh My!

I don’t know about you, but sometimes I read all of the egg cartons and just scratch my head: what does all of this mean?! I want eggs from chickens who are free, well-fed, and exposed to the least amount of hormones/additives possible. It’s important to learn which labels meet my standards (or close to them), and I hope these descriptions inform yours as well:

UEP Certified Regular and/or Cage-Free: Egg cartons receive these labels when the producers implement the standards of the United Egg Producers, namely, that the hens are raised on farms committed to responsible, scientific-based methods that ensure optimal hen care (whether or not the hens are caged).

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Free Range: These eggs are not produced with specific standards in place, however the common denominator is that the hens that produce these eggs have some access to the outdoors. Free range eggs are typically produced in smaller quantities.

USDA Certified Organic: Organic eggs are produced on farms that abide by the standards of the United States Department of Agriculture including hen diet and access to the outdoors. See here for more details.

There are many more labels and logos that egg producers can put on their cartons, including humane certifications, vegetarian diets (chickens are typically omnivores), and enriched with various nutrients. The most common enriching nutrient is omega-3.

When purchasing eggs, you may also notice a grade and size. Eggs are graded based on appearance (both interior and exterior). Grade AA indicates an egg with a firm egg white, a bulbous yolk, and a clean, uncracked shell. Grade A is similar to grade AA, except that the egg whites may not be as thick and firm. Grade B eggs may have thinner egg whites, flatter yolks, and stained shells. These eggs are typically used for liquid, frozen, or dried products.

The size of the egg changes the nutrients accordingly, as different sized eggs have different amounts of yolk and egg white. Small eggs are generally 18 oz, medium 21 oz, large (standard) 24 oz, extra-large 27 oz, and jumbo 30 oz. Size ultimately is not anything worth worrying about, just something to be aware of (especially if you’re cooking for a crowd!).

Eating eggs 

plate of scrambled eggs

Now for the delicious part! There are so many ways to cook eggs for breakfast, lunch, and dinner! Just googling “ways to cook an egg” brought up over 20 different options. In order to get the full benefits from your egg, it is best to eat it as part of the meal itself. That is to say, making something where eggs are an ingredient (like cake) does not automatically make it a healthy meal. The composition of eggs changes when they are mixed with certain ingredients and exposed to heat and/or cold. This change in composition can either enhance or detract from the nutrients that are inherent to the egg. So, eat cake (in moderation), and make space on your plate for a good scramble or hard-boiled egg when you can.

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My favorite way to eat an egg is sunny side up. I love eating the runny yoke with a piece of toast! Mmm, it’s delicious. Unfortunately, my husband doesn’t share my love of runny yokes. He’s a scrambled kind of guy. And now he’s brain-washed our girls to like scrambled eggs as well. But that’s okay. My girls (and soon to be Shep as well) still get the benefits of eggs whether they eat them sunny side up or scrambled.

Recipes with eggs

You might prefer to enjoy eggs hard boiled, scrambled, or any other way. But maybe you want to add some variety. If that’s the case, then I have a few recipes to share with you.

Here are a few of my favorite recipes that include eggs:

On The Go Egg Cups

Best Ever Chocolate French Toast

Strawberries & Cream French Toast

Gluten-Free Blueberry French Toast Casserole

Banana Walnut Pancakes

Adding eggs as a regular component of your healthy diet is easier than it may seem, and I can’t wait to see how this little food makes a big difference for you!

What’s your favorite way to enjoy your eggs? Are you Team Scrambled or Team Sunny Side Up (or a different way altogether)? Let me know in the comments below.


Sources:

  1. https://www.eggnutritioncenter.org/egg-nutrition-basics/

  2. https://www.incredibleegg.org/egg-nutrition/

  3. https://www.exploratorium.edu/cooking/eggs/eggcomposition.html

  4. https://eggsafety.org/types-of-eggs/

  5. https://uepcertified.com/what-do-label-on-egg-cartons-mean/




About the author:

Kara Swanson is a certified nutritionist and founder of Life Well Lived. She is married to her best friend and the proud mother of three. Her passion is to make nutrition simple+easy+delicious!