Eggs (Gallus gallus domesticus) are regarded by many as a “superfood”. This is because they are highly nutritious, containing high-quality protein, healthy fats, vitamins and minerals. In addition, they provide several other benefits that contribute to overall health and wellness. Eggs are a staple in many diets and have been prominent for centuries in several different cuisines. While they have occasionally been controversial due to their cholesterol content, many health professionals consider them a nutrient-dense, versatile food option.

Fun Fact
The average hen lays around 300–325 eggs per year.

Keep reading to find out all you need to know about eggs.

History & Facts

Eggs have been consumed by humans for thousands of years. They were likely eaten raw from wild bird nests by early humans before the domestication of chickens. Ancient Egypt and China were the first societies documented to have domesticated hens for their eggs as far back as 1500 BC.

Today, chicken eggs are the most widely consumed type of egg around the world due to their ease of availability and versatility with different cooking methods. They’re also part of cultural practices like Easter.

Eggshell Color

The breed of the chicken typically determines the color of the eggshell. Hens with white feathers generally produce white eggs, while those with brown feathers lay brown-shelled eggs.

Types of Chicken Eggs

In the U.S., the USDA uses a grading system to classify eggs. The types of eggs available on the market include the following

  • Conventional (Non-cage-free): This refers to the intensive farming method whereby eggs come from hens predominantly living in cages.
  • Cage-free: Hens are free to roam inside barns, but they do not have access to outdoor space.
  • Free-range: Hens must have unlimited access to food and water, freedom to roam within an area, and continuous access to the outdoors during their laying cycle.
  • Organic: These eggs must carry the USDA Certified Organic label. This means farmers house the hens according to USDA’s organic standards. The hens eat a vegetarian diet that is free from pesticides and antibiotics which is also part of the organic standards. They also have access to the outdoors.

Eggs can also be classified by grade, for which farmers pay a fee to obtain official grading. Eggs can be graded as AA, A, or B, depending on the quality of the product and the condition of the shell.

Nutrition Facts

Macronutrients

A large (50 g) hard-boiled egg offers a concentrated dose of nutrients (1):

  • Calories: 77.5 kcal
  • Protein: 6.3 g
  • Total Fat: 5.3 g
  • Carbohydrate: 0.56 g
  • Cholesterol: 186 mg

Vitamins & Minerals

Eggs also provide essential vitamins and minerals (1):

  • Vitamin B12: 0.555 µg (23% of RDA)
  • Vitamin A: 74.5 µg RAE (8% of RDA)
  • Vitamin D: 1.1 µg (≈43.5 IU) (7% of RDA)
  • Vitamin E: 0.515 mg (3% of RDA)
  • Selenium: 15.4 µg (28% of RDA)
  • Riboflavin (B2): 0.257 mg (20% of RDA)
  • Pantothenic acid: 0.7 mg (14% of RDA)
  • Folate: 22 µg (6% of RDA)
  • Iron: 0.595 mg (7% of RDA)

Other Important Nutrients

Eggs are especially high in choline (147 mg per large egg), a nutrient important for cell membranes and early brain development. Many people don’t get enough choline from their usual diets (2). Interestingly, choline from egg yolks seems to be absorbed more efficiently than choline from other dietary sources (3).

Eggs also have lutein and zeaxanthin (~176 µg per large egg) (1), antioxidants that may help protect vision. Egg whites contain lysozyme, an enzyme with antimicrobial properties (4).

Summary
Eggs provide high-quality protein, choline, and many key vitamins and minerals, which makes them a nutrient powerhouse.

Egg Health Benefits

Eggs aren’t just a breakfast staple; they’re studied for benefits covering heart health, healthy body weight, brain function, and more. Here are some of the many health benefits of eggs:

Supports Heart Health

  • Eggs May Improve Cholesterol Ratios: Many studies have found that a moderate intake of eggs doesn’t negatively affect blood cholesterol levels in healthy people, and may even support healthy LDL-to-HDL ratios (5, 6).
  • Moderate Consumption May Reduce Stroke Risk: Some large reviews have hinted that moderate egg consumption might slightly lower stroke risk, although more research is needed (7, 8).

Child Growth & Development

  • Early Egg Introduction Improves Infant Growth: Introducing eggs early to infants (around 6-9 months) has been linked to better infant weight and length measurements, which may help address underweight issues in some cases. (9, 10).
  • Provides Important Nutrients for Children & Teens: The protein, choline, and other vital nutrients in eggs help encourage proper growth and development in children and teenagers (11).

Helps with Blood Sugar & Metabolic Support

  • Eggs May Improve Insulin Sensitivity: Some research trials have shown that adding eggs to a balanced eating plan can help with controlling blood sugar, while typically not raising LDL levels (12, 13).
  • Conflicting Research for Higher Intakes: Some population studies in Western countries hint that eating 3 or more eggs per week may raise type 2 diabetes risk; however, this pattern isn’t consistent across all populations, as other studies suggest that eating an egg a day may still lower the risk of insulin resistance (14, 48).

Supports Weight Management & Satiety

  • Eggs Boost Fullness: Their top-quality protein can help you feel more satisfied and potentially eat fewer calories later (15, 16).
  • Aids Weight Loss Efforts: Several studies note that in the context of eating fewer total calories, eggs may help lower body weight or improve body composition (17, 18).

Eye Health

  • Eggs Protect Against Age-Related Macular Degeneration: Lutein and zeaxanthin found in egg yolks may help protect the retina and possibly lower the chance of age-related macular degeneration (19, 20).

Brain & Cognitive Support

The choline in eggs may:

  • Help Infants’ Brain Development: Providing eggs in the diet early on might improve choline and DHA levels in infants (10).
  • May Support Cognition in Older Adults: Choline is required to make key neurotransmitters, which could help support cognition. Scientists continue to study how eggs may support the aging brain.
Summary
Eggs may have wide-ranging benefits, from potentially helping heart health to aiding weight management and supporting eye and brain function. For many, moderate egg consumption can be a valuable, tasty part of a balanced diet.

Affordability & Food Security

Eggs tend to be cheaper than many other animal proteins while still delivering important nutrients, like choline and vitamin D. Multiple research analyses confirm eggs are a cost-effective source of high-quality protein and other nutrients (21). For individuals and families experiencing food insecurity, adding eggs can help fill protein gaps at a lower cost (22). In resource-limited regions, egg-based nutritional interventions have shown promise for improving overall growth in undernourished children, although effects on height gain have been inconsistent (23).

Risks & Side Effects

Eggs are generally safe, but you should be aware of a few considerations:

  • Cholesterol Sensitivity: Some individuals, called “hyper-responders”, have a genetic predisposition that causes their LDL cholesterol to rise more noticeably when consuming dietary cholesterol from eggs. These individuals may see a slight rise in LDL cholesterol from eggs (24), but many people—even older adults—do not experience a harmful spike in LDL/HDL ratios (25).
  • Type 2 Diabetes Risk: Certain large-scale observational studies in Western countries link higher egg consumption (3 or more eggs per week) to a greater chance of developing diabetes, although other research demonstrates that regular egg consumption likely reduces the risk of developing insulin resistance (26, 14, 47).
  • Cancer Associations: Older observational research hinted at a link between egg consumption and some cancers. However, more recent studies don’t show a strong connection. For example, recent studies found no major connection with prostate or breast cancer (27, 28).
  • Allergies: Egg allergies are one of the most common food allergens, especially in children, though they can develop later. Interestingly, early introduction of eggs might reduce allergy risk (29, 30). However, severe reactions can still happen (31). Heating eggs thoroughly might help in some cases, but some allergic individuals still react even to highly cooked eggs (32).
  • TMAO Concerns: There’s been talk about whether egg-based choline spikes levels of trimethylamine-N-oxide (TMAO), which some studies have associated with increased heart disease risk. The research results are mixed, and eggs generally don’t boost TMAO much in healthy people (33, 34). Notably, a separate trial found that supplemental choline (choline bitartrate) raised TMAO levels, but consuming the same amount of choline from whole eggs did not have this effect (35).
Summary
For most people, moderate egg intake is generally safe. Potential issues can include allergies, individual cholesterol responses, or certain metabolic concerns. Personalized guidance may be necessary if you have a known sensitivity, allergy, or specific health needs.

Buying & Storing Eggs

  • Packaging: Check if the carton is cold and the eggs aren’t cracked. Note the “sell by” or “use by” date.
  • Refrigeration: Keep eggs at ≤4°C (≤40°F) to maintain freshness and slow bacterial growth.
  • Best If Used: Try to use them within about 3 weeks of purchase for optimal quality.
  • Check Cleanliness: Discard any eggs with cracks or strong, unpleasant odors.

Note on Citric Acid Spraying: Early studies show that spraying egg shells with a citric acid solution can slow down quality loss over time (36).
Freezing Egg Yolks: For culinary or industrial uses, freezing yolks can cause a “gel” texture. Researchers are exploring methods, such as adding salt or sugar, to keep them from gelling (37).

Cooking With Eggs

  1. Boiled or Poached: Quick methods that retain many nutrients and don’t require extra oil.
  2. Scrambled or Fried: Use minimal oil. Including veggies like spinach or peppers adds taste and fiber.
  3. Omelets & Frittatas: Combine eggs with veggies, cheese, or lean meat for a satisfying dish.
  4. Baking & Beyond: Eggs act as binders and help create structure in baked recipes.
Note
High temperatures or frying for a long time can reduce certain nutrients. Cooking eggs at moderate heat helps keep more of the vitamins and antioxidants in the yolk.
Warning
Eating raw or undercooked eggs may lead to Salmonella infection (38, 39). Cooking your eggs thoroughly or using pasteurized eggs/products can help lower this risk.

Do Eggs Raise My Cholesterol?

Research shows that the cholesterol in eggs isn’t highly absorbed by the body in many people, so eggs don’t usually cause a big jump in blood cholesterol (40). Still, if you have a known genetic tendency or are at higher cardiovascular risk, ask your healthcare professional for personalized advice.

Should I Eat the Yolk or Just Egg Whites?

Egg whites are mostly protein and contain no cholesterol, but most vitamins and other helpful compounds (choline, lutein, zeaxanthin) are found in the yolk (41).

What About Omega-3–Enriched Eggs?

Omega-3-enriched eggs come from hens fed diets containing fish oil, flax, algae, or specialized seeds. Eating omega-3-enriched eggs can increase your EPA/DHA levels and may help support blood vessel health and healthy blood pressure (42). More novel feeds, such as Ahiflower oil (high in stearidonic acid) or microalgae, can boost egg yolk DHA even further (43, 44).

Are Eggs Sustainable?

Compared to several other animal proteins (like beef), eggs often leave a smaller carbon footprint and require fewer natural resources, which makes them a potentially more eco-friendly choice (45).

How Many Eggs Can I Safely Eat?

Many guidelines suggest that consuming up to one egg per day is fine for most healthy adults (7, 46). However, your overall diet and individual risk factors matter too.

Conclusion

Eggs are a versatile, budget-friendly, and nutrient-packed option that fits well into many diets when eaten reasonably. They deliver high-quality protein, vitamins, choline, and antioxidants like lutein and zeaxanthin, which are nutrients that support growth, metabolic health, and possibly even heart and brain function. Studies also highlight how affordable eggs can help address food insecurity in certain populations.

Although eggs have occasionally been questioned because of their cholesterol content, modern research shows that moderate consumption rarely increases heart disease risk and may even boost some helpful health measures. Some groups, such as pregnant individuals (47), people who are very sensitive to cholesterol, or those with specific metabolic issues, may need personalized advice. Ongoing research also examines the nuances of eggs and TMAO, specialized egg-white protein supplementation in medical settings, and the role of enriched eggs for particular needs.

By adding eggs to a balanced eating plan, you can tap into the impressive potential of this versatile food. With strong evidence and ongoing scientific interest, eggs continue to be a practical, nutritious, and cost-effective option for many.

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