In this article:
- Eggs are replete with high-quality protein as well as vitamins, minerals, antioxidants, and essential fatty acids that most other protein-rich foods lack.
- Both the white and yolk have distinctive nutritional makeup that offers different health and chemical benefits.
- Eggs can improve your health in several ways, ranging from enhancing brain function to aiding weight loss, ensuring a healthy pregnancy, and promoting muscle buildup, to name a few.
- Overconsumption of raw eggs can lead to a biotin deficiency. This deficiency is characterized by dry skin, rashes, brittle hair, hair loss, and fatigue.
- People diagnosed with kidney disease, diabetes, or celiac disease are usually advised caution regarding egg consumption.
Eggs are among the most universal and versatile dietary staples. Chickens eggs are the most popular variety in the United States. However, various cultures around the world eat eggs from other birds, such as ducks, ostriches, and quail.
The complexity of eggs allows them to have a range of functions in food while also providing nutrients necessary for optimal health.
This article will review the composition, nutritional value, and health benefits of eggs, as well as some cautions and tips when selecting and preparing eggs.
The Inside of An Egg
The egg is made up of two-thirds egg white and one-third yolk. Both the white and yolk have distinctive nutritional makeup that offers different health and chemical benefits.
The egg white also called the albumen, surrounds the yolk. The two sections are separated by the vitelline membrane. The chalazae extend through the thick and thin albumen, keeping the yolk in position by anchoring it to the shell.
Egg whites are classically labeled as “diet food” because they are low in calories, fat-free, and high in protein.
|Nutrient||Egg White||Egg Yolk|
|Calories||17 calories||55 kcal|
|Fat||0 g||4.5 g|
|Cholesterol||0 mg||184 mg|
|Protein||3.6 g||2.7 g|
|Sodium||55 mg||8 mg|
On the other hand, the egg yolk is demonized for its high cholesterol content.
Recent research shows that cholesterol in foods does not necessarily correlate with blood cholesterol levels. (1)
Registered dietitians have shifted their focus from minimizing dietary cholesterol and fat to optimizing the type of fat in the diet. Saturated fats are associated with increased risk of heart disease, whereas unsaturated fats are associated with decreased risk. (2)
While one large egg yolk contains 1.5 grams of saturated fat, it also has 3.5 grams of unsaturated fat, including omega-3 fats. Egg yolks can safely be included in a heart-healthy diet plan.
The advice to toss out the yolk and only eat the egg white is outdated. The yolk contains 40% of the protein in an egg as well as many vitamins, minerals, antioxidants, and essential fatty acids:
- Egg yolks are one of the few natural food sources of vitamin D. The fat-soluble vitamins A, D, and E in eggs require fat from the yolk to be absorbed by the body.
- Many people struggle to eat enough omega-3 fats and rely on fish oil supplements. Omega-3 fats are not common in foods. Fatty fish, walnuts, flaxseeds, and eggs are some of the only good food sources.
- Lutein and zeaxanthin are antioxidants commonly found in dark green leafy vegetables. Many people do not eat enough vegetables to provide adequate antioxidant power. Eggs are nonvegetable sources of these nutrients.
Some of the yolk’s keynote nutrients are commonly deficient in the diets of Americans.
Eggs contain the following nutrients. (3)
|Nutrient||Amount in 1 Large Egg||% Daily Value|
|Total Fat||5 g||6%|
|Saturated fat||1.5 g||8%|
|Vitamin D||1 mcg||6%|
|Vitamin A||80 mcg||8%|
|Vitamin B12||0.2 mcg||20%|
With only 70 calories, one egg provides 12% of the daily value of protein and is high in riboflavin, biotin, vitamin B12, iodine, selenium, and choline. Eggs also provide vitamin D, vitamin A, folate, phosphorous, omega-3 fats, and the antioxidants lutein and zeaxanthin.
Eggs do not contain any sugar, carbohydrates, or vitamin C.
What does it mean that eggs have “high-quality protein”?
Amino acids are the building blocks of protein. The unique pattern of amino acids gives a protein its function.
Nine of the amino acids are “essential.” This means that our bodies cannot make them, but they must be supplied in the diet. The essential amino acids are histidine, isoleucine, leucine, methionine, valine, tryptophan, threonine, phenylalanine, and lysine.
If one essential amino acid is absent, body processes are hindered.
A high-quality protein provides all the essential amino acids in a pattern that matches what the body needs.
The biological value is a tool used to show the quality of a protein. Eggs have one of the highest biological values of 93.8%. This means that they supply amino acids in a pattern almost exactly fit to what the body needs.
Milk has a biological value of 84.5%, fish 76%, and beef 74.3%. Based on the biological value, eggs rank at the top of protein quality, second only to human breast milk.
Does that mean that egg protein is better than meat protein?
While eggs have a higher biological value than meat, meat has more protein per ounce.
The keys to any healthy diet are moderation, portion size, and variety. Eggs and meat both have their advantages. Both can contribute needed nutrients and protein to an overall healthy diet.
Benefits of Eating Eggs
Eggs provide a variety of nutrients and therefore have many health benefits.
1. Improves Brain Function
Lecithin is a type of fat found in egg yolks and is made up of fatty acid, a phosphate group, and choline. Choline is an essential but often forgotten, nutrient.
Adequate choline intake is associated with better memory and learning abilities. (4)
It contributes to neurological health in several ways:
- Choline and vitamin B12 participate in the chemical reaction that prevents the buildup of homocysteine in the body. High homocysteine levels are associated with an increased risk of Alzheimer’s disease. (5)
Adequate intakes of choline and vitamin B12 prevent homocysteine buildup and cognitive decline. (5)(6) One egg provides 20% of the daily value of vitamin B12 and 25% of the daily value of choline.
- Choline is used to make acetylcholine, an important neurotransmitter that influences memory. One hallmark symptom of Alzheimer’s disease is decreased acetylcholine function.
Research is still in its infancy; however, some scientists hypothesize that choline supplementation could be used to treat memory disorders such as Alzheimer’s disease. (4)
- Choline is used to make phospholipids, which make up the structure of cell membranes. Healthy cell membranes allow nerve impulses and chemical signals to travel efficiently. This permits quick reaction times.
- Mothers must have an adequate intake of choline before and during pregnancy for proper infant brain development. Choline plays a critical role in the formation of the brain’s memory center, the hippocampus. (7)
2. Aids in Maintaining a Healthy Weight
Eggs are perfect for the morning meal. The combination of fat and protein in eggs helps promote long-lasting fullness. Dieters that eat a well-rounded breakfast are more likely to be successful due to reduced cravings and overeating throughout the day.
Many people find that eating eggs helps them feel more satisfied on a low-calorie diet. This allows them to lose weight without feeling hungry and deprived.
While any low-calorie diet can promote weight loss and weight maintenance, eggs can be a part of a healthy weight control plan. If not carefully planned, a low-calorie diet can be deficient in nutrients and protein.
Eggs are nutrient dense, provide high-quality protein, and contribute to overall diet quality. High-quality protein, such as eggs, promote maintenance of muscle mass during moderate weight loss. (8)
In a recent clinical trial, overweight or obese older adults were randomized to a high-protein diet, including three eggs per day or a lower-protein diet with no eggs for 12 weeks. (8)
The diets both created a calorie deficit. Therefore, the two study groups lost a similar amount of weight. However, the high-protein group retained more muscle mass compared with the participants on the lower-protein diet.
3. Facilitates Muscle Building
Research confirms that protein is essential for muscle recovery and growth. (9)
During the critical 2 hours following resistance exercise, protein is efficiently used to build muscle. High-quality protein can be quickly absorbed and efficiently utilized to optimize muscle growth and help athletes “get the most” out of their workouts.
Egg protein has a high biological value and is a good choice for muscle building after exercise.
As most of the protein is in the egg white, should you skip the yolk for your post-workout snack?
No! If you skip the yolk, you miss out on many nutrients that are not in the white.
One study compared the muscle growth of young men that ate 18 grams protein from whole eggs or egg whites after a resistance exercise. They found that whole eggs stimulated muscle growth significantly more than egg whites alone. Do not throw out the yolk! (9)
Adequate protein is essential for muscle building. However, excess protein does not lend added benefits for muscle growth. Protein utilization is maxed out at about 20-25 grams of high-quality protein at one time.
When consumed over this amount, protein is no longer used for muscle growth, but it is simply used for energy or stored as fat.
To maximize muscle growth and workout recovery, consume a snack, including 20-25 grams of protein, carbohydrates, and fluids within 2 hours of the workout. Hardboiled eggs are a portable and easy way to add protein to a post-workout snack.
Caution: The myth that eating raw eggs is better for muscle building is not true. Eggs may contain Salmonella that can cause sickness or death, so never consume them raw. Always cook eggs or buy pasteurized products.
4. Promotes a Healthy Pregnancy
The egg is designed to protect and nourish a chick as it develops within the shell. Many of the nutrients needed to nourish the chicken embryo also benefit a human fetus during pregnancy.
Choline is needed for cell reproduction and growth. If mom does not consume adequate choline during pregnancy, the baby has a higher risk of neural tube defects and improper brain development. (10)
Eggs are also good sources of omega-3 fats that are essential for early brain growth. The critical developments that occur during pregnancy contribute to lifelong brain function and memory.
One study found that infants of women who took choline supplements during the third trimester of pregnancy had significantly faster reaction times and memory compared with those that did not. (11)
More research is needed to determine the effect of choline supplementation during pregnancy and the long-term effects on the offspring. However, eggs clearly provide essential nutrients, including choline, omega-3 fats, and protein, that help with healthy fetal development.
Caution: Pregnant women should not consume eggs that are raw or unpasteurized due to the risk of Salmonella infection.
5. Strengthens Bones
Calcium and milk are important for building and maintaining strong bones. Although sometimes overlooked, phosphorus and vitamin D are also essential pieces of the puzzle.
Phosphorus and calcium make up the mineral structure of bones. Both are needed in adequate amounts to build healthy bones. One egg provides 15% of the daily value of phosphorus.
Vitamin D regulates calcium in the body. It controls how much is absorbed from the food you eat, how much is excreted in urine, and how much is incorporated into bones.
Inadequate vitamin D in the body causes bones to soften. In children, this is known as rickets. Rickets is characterized by the curved, bowed legs of children with bones that are not strong enough to hold the body upright.
Eggs, liver, and fatty fish are among the only natural food sources of vitamin D. One egg provides 6% of the daily value of vitamin D.
A cross-sectional study in 2018 found that daily egg consumption was associated with greater bone density in 13-year-old adolescents. (12) Another study on dogs found that dog food fortified with egg hydrolysate increased bone formation. (13)
As part of a healthy diet including calcium-rich foods, eggs can help promote healthy bone growth and maintenance.
6. Improves Mood
Low levels of B vitamins are associated with depression. (14) Vitamin B12 is mostly found in animal products. For people who do not eat meat, it can be difficult to get enough B12. Eggs are a reliable source of B12 and other B vitamins for those who do not eat meat.
Also, several of the essential amino acids in eggs are used to make signaling molecules in the body that regulate sleep and mood hormone levels.
7. Protects Eye Health
Antioxidants protect the body from free radicals that are produced during normal body processes and UV light from sun exposure.
The antioxidants in eggs, namely, lutein and zeaxanthin, are found in the eye pigments of the retina. Lutein and zeaxanthin prevent cell damage in the retina and reduce the risk of macular degeneration.
8. Promotes Skin and Hair Health
Eggs can be a beneficial addition to your beauty routine. Many of the nutrients in eggs promote healthy skin, nails, and hair:
- Protein and collagen help keep skin taut and wrinkle-free. Keep in mind that applying eggs to the skin directly may not improve skin health.
The proteins in eggs are too large to pass through the small pores on the skin surface. Eggs must be eaten to reap the benefits from the protein and collagen.
- Melanin is the dark pigment produced in the skin following sun exposure. It is responsible for the skin discoloration that occurs with aging. Phosvitin and phosphoglycoprotein are proteins in the egg yolk that control excessive melanin production. (18)
- Biotin helps keep skin and hair cells healthy. Eggs contain 15% of the daily value of biotin.
- Eggs can even be used as a shampoo. It is high in protein and nutrients that cleanse, shine, and nourish hair.
Caution: Eggs provide the body with many vitamins, minerals, protein, and antioxidants. However, there are risks associated with consuming eggs that warrant extra precaution.
Types of Eggs
Eggs must be chosen, handled, stored, and prepared properly in order to enjoy their benefits. Marketing has a significant influence on the purchasing choices of consumers.
It is important to be aware of what the marketing claims mean when considering which items to choose. Some of the types of eggs on the market include:
- Conventional cage eggs: Hens live in a climate-controlled room with 60-80 square inches to move around in.
- Cage-free eggs: Hens live in a climate-controlled room with about twice the space as conventionally caged hens.
- Free-range eggs: Hens live in a barn that also has access to an outdoor area where they can roam freely. This does not necessarily mean that the hens spend time outside, but they do have access to it. The outdoor area may be a small porch attached to the barn with cement flooring.
- Pasture-raised eggs: Hens have at least 108 square feet to roam outdoors.
- Organic eggs: Hens are usually free-range or pasture-raised and are given certified organic feed. Organic feed is produced without pesticides and other chemicals.
- Nutritionally enriched eggs: Hens are fed extra omega-3 fats or vitamins such as vitamins D and E. The eggs from these hens have higher levels of these nutrients.
- Processed eggs: Deshelled and processed into an egg product. Processed eggs include liquid, dried, and frozen eggs.
- Brown eggs: The color of an egg is determined by the breed of hen and type of poultry feed. Color does not reflect the nutritional value.
- Local eggs: Produced by farmers in your area. These eggs are often available at farmers’ markets.
- Grade AA, A, and B: Grading reflects the quality of the egg, but not the nutritional value.
Grade AA is the highest quality, and B is the lowest. Grading is determined by the integrity of the shell, shape, and size of the yolk, presence of blood or meat spots, and thickness of the white.
- Size: Chicken eggs range in size from peewee to jumbo. Large eggs are the preferred sizes in most recipes.
The type of egg you choose depends on your needs and priorities.
Free-range, pasture-raised, and organic eggs are typically the most expensive. These eggs are not more nutritious than conventional eggs.
Many people choose these eggs because hens are happier and healthier in these environments. Organic hens are also less likely to lay eggs contaminated with pesticides.
The hen’s living environment, shell color, and grade do not influence the nutritional value of the egg. Nutritionally enriched eggs have higher amounts of the nutrients fortified in the hen’s diet.
Is Egg Always Safe to Eat?
Salmonella Poisoning: Salmonella in eggs can cause sickness and death. Raw eggs should always be cooked or pasteurized before consumption.
Biotin Depletion: Biotin is a vitamin known for its beneficial effects on skin and hair health. Avidin, a protein in eggs, binds tightly to biotin and prevents it from being absorbed in the intestines. Cooking denatures avidin and prevents it from binding to biotin.
Overconsumption of raw eggs can lead to a biotin deficiency. This deficiency is characterized by dry skin, rashes, brittle hair, hair loss, and fatigue.
Raw eggs should always be cooked to prevent foodborne illnesses and biotin deficiency.
Protein Overload: The kidneys normally excrete the excess ammonia that is created during protein metabolism.
Ammonia overload can be fatal. People with kidney disease are not able to remove ammonia from the body as efficiently. Thus, those with poor kidney function should consult their doctor or registered dietitian to determine how much protein is safe for them to eat.
For those who do not have kidney disease, there is no recommendation for how many eggs are safe to eat. In reasonable portions, eggs can be a healthy addition to a well-balanced diet.
Eating Eggs If You Have Certain Medical Conditions
With careful planning, eggs can be included in the diets of people with medical conditions.
Kidney disease: In proper portion sizes, eggs can provide needed protein for those with kidney disease with or without dialysis. However, the yolk is high in phosphorus, which may need to be limited depending on the stage of kidney disease.
If you have kidney disease, you should consult your doctor or registered dietitian to determine whether eggs can fit in your meal plan.
Celiac disease: Eggs are naturally gluten-free and can be included in a gluten-free diet plan. Some products that contain eggs may have gluten as an added ingredient. Always check the food label to be sure.
Diabetes: Eggs do not contain any carbohydrates. When paired with a moderate portion of carbohydrate foods, the protein in eggs can help prevent blood sugar spikes following meals and snacks.
Can Egg Cause Allergy?
See a medical provider if the child has any of these symptoms after eating eggs, which indicate an allergy:
- Upset stomach
Although most of the allergenic proteins are part of the white, the yolk can also trigger allergic reactions. Thus, if a child has an allergy, both the egg yolk and white must be avoided. Also, proteins can still cause allergic reactions after being cooked.
Fortunately, many children will outgrow an egg allergy by age 6.
Eggs are widely used in products as an ingredient. Guardians of children with an egg allergy must learn to read food labels and identify products that contain eggs.
Products that often have eggs include:
- Baked products such as bread, cookies, and cakes
- Mayonnaise and salad dressing
- Some pasta
- Hair care products
How to Store Eggs
Consider these tips for storing your eggs:
- Eggs should be stored in the fridge on the main shelves, not the door. This ensures they remain at a safe temperature.
- Store eggs in the carton. The eggshell has tiny pores that allow odors and flavors from other food in the fridge to enter the egg. The carton keeps eggs fresh by blocking this contamination.
- Pay attention to the expiration date on the container.
- When stored in the fridge, eggs can still be used 3-4 weeks after the expiration date. However, their quality may be reduced due to the thinning egg white.
- Older eggs will not be as effective in recipes where they are needed for leavening, foaming, or emulsifying such as waffles, desserts, and meringues. Older eggs go great in omelets and frittatas or eaten poached, scrambled, or hard-boiled.
- Unwashed farm eggs have a longer shelf life than washed eggs from the grocery store. Washing removes the natural protective layer, called the bloom that prevents bacterial contamination.
|Egg||Recommended Storage Time|
|Store-bought shell eggs||3-4 weeks or best by date|
|Unshelled yolks or whites||2-4 days|
|Hard-boiled eggs||1 week|
|Egg dishes||3-4 days|
|Pickled eggs||1 month|
|Frozen whole eggs||4 months|
|Unwashed farm eggs||6-8 weeks unrefrigerated or 3 months refrigerated|
How to Use Eggs in Your Recipes
In addition to adding flavor, color, and texture, the unique chemical makeup of eggs makes them useful in many cooking applications. Here are a few of the many ways that eggs are useful in the kitchen:
- Eggs are natural emulsifiers. An emulsifier helps water and fat mix together when they normally separate. This quality is useful in salad dressing, mayonnaise, ice cream, and baked goods.
- Eggs provide leavening. The egg white produces foam when whipped and can incorporate air into baked goods including waffles and sponge cakes.
- Eggs are binders. When eggs coagulate, they bind the ingredients of a recipe together. This keeps meatloaf, crab cakes, and baked goods from being crumbly.
- Eggs are used as a glaze. When brushed on baked goods, an egg wash gives products a shiny crust.
- Eggs are thickening agents. Eggs thicken pudding, sauces, and custards.
Popular Egg Preparations
Eggs can be enjoyed in so many ways. Here are easy and healthy ways to incorporate eggs into your diet:
- Eggs can be prepared without added fat by boiling, poaching, or scrambling.
- Get your protein and a healthy helping of vegetables by loading an omelet or frittata with spinach, mushrooms, onions, and tomatoes.
- Hard-boiled eggs are portable and can be a healthy post-workout or lunchbox snack.
- Use chopped boiled eggs as a salad topper.
- Make homemade breakfast burritos and freeze them for a quick breakfast go-to.
|Culture||Classic Egg Dish|
|United States||Egg salad sandwich|
|North Africa and Middle East||Shakshuka: poached eggs in spicy tomato sauce|
|France||Sweet and savory, fluffy souffle|
|China||Egg drop soup|
|Mexico||Huevos Divorciados: divorced eggs. A breakfast of a pair of fried eggs - one with red and the other green salsa.|
|Germany||Quiche Lorraine: egg filling in a pastry crust|
|Japan||Tamagoyaki: a rolled omelet|
|Italy||Deviled eggs: originated in Ancient Rome. Eggs + Mayo + mustard + your choice of spices|
|Philippines||Kwek Kwek: battered and fried quail eggs|
|Sri Lanka||Egg hoppers: street food. Cooked eggs served in a pancake bowl|
|Scotland||Scotch eggs; Hard-boiled egg wrapped in sausage meat and coated in breadcrumbs|
Eggs add high-quality protein and an array of nutrients to a well-balanced, healthy diet. With the number of health benefits and uses of eggs in the kitchen, it is no wonder they are eaten and loved worldwide.
Expert Answers (Q&A)
Answered by Lily Chen, MS, RDN, APD, FAND
In general, eggs offer a wealth of benefits. Boiled eggs, in particular, are a great choice as a nutritious snack or as an integral part of the main meal eaten daily.
It is healthier to eat the whole egg to receive optimum nutrients. The egg yolk contains lutein and zeaxanthin, the antioxidants shown to be beneficial for eye health.
The egg yolk is also a rare food source that naturally contains vitamin D. In addition, half of the protein found in eggs is in the egg yolk.
Nutrients found in eggs such as lutein, vitamin A, D, E, K are fat-soluble, which means it is best absorbed in the body with fat. Since eggs already contain fat, it is a healthy choice by itself.
All foods should be consumed as part of a balanced diet. An egg or two a day is a great way to meet protein and nutrient needs.
Raw eggs are unsafe as they may contain salmonella.
Eating eggs daily by itself is not the main culprit for weight gain as its high amount of protein helps to keep you full and satisfied.
It is usually what you eat with your eggs, which causes weight gain. Instead of processed meats such as bacon or sausage, pair eggs with nutritious sides such as a vegetable, fruit, or whole grains.
Signs of mild or moderate allergic reactions to eggs are swelling, hives, tingling mouth, abdominal pain, vomiting, eczema, rashes.
Signs of a severe reaction or anaphylaxis are difficult/noisy breathing, swelling of tongue or throat, difficulty talking, wheezing, persistent cough, dizziness or collapse.
Eggs are a source of high-quality protein that helps with body growth and repair, including hair.
Eggs have one of the highest amounts of choline compared to other foods. Choline is an important nutrient to consume during pregnancy as it supports fetal brain development.
Athletes may also consider including eggs into their diets. Post-workout recovery is essential for optimal training and performance. Combining a high-quality protein such as an egg with an easily digestible carbohydrate can help to refuel muscles and promote recovery.
About Lily Chen MS, RDN, APD, FAND: Ms. Chen is a dietitian with a wealth of experiences in clinical care, teaching, management, and research.
She has been recognized as a Fellow of the Academy of Nutrition and Dietetics which signifies she has lived up to the Academy’s values of customer focus, integrity, innovation and social responsibility. Lily was nominated by her peers to serve as Nominating Committee Chair for the professional dietetic practice group Dietitians in Business and Communications.
She currently serves as Strategic Communications Chair for the International Affiliate of the Academy of Nutrition and Dietetics and as Global Representative for Professionals in Nutrition for Exercise and Sport. She currently sees patients at Sydney Cognitive.