The Sunny Side Up of Eggs

Unscrambling the Truth About Their Nutritional Value

While eggs are a breakfast staple, the debate around their health benefits and risks continues to unfold. Nutrition researchers and scientists have long questioned their nutritional value. In fact, the American Heart Association (AHA) once recommended that people eat no more than three whole eggs a week.1 Now, the organization has given the public the greenlight to eat up to one egg per day.2,3 Researchers have come to understand that the former recommendation was based upon misinterpreted data. Still, the debate remains. Here’s is what we do know about eggs. 

History

Of the vast variety of foods we eat, only eggs have been specifically singled out for restriction in a public health effort to reduce cardiovascular disease (CVD) risk.1 This is due to the yolks’ high levels of cholesterol.4 When the AHA issued their egg advice in 1968, Americans listened. The egg industry saw a substantial drop in consumption over the subsequent years. The AHA updated their advice to their current recommendation in 2015. Since then, egg consumption has steadily risen.5 Now, more than 50 years of research shows that moderate egg intake is not associated with increased health risk. On top of that, experts say this small-but-mighty food is worth incorporating into our diet.6

Nutritional Value

The egg’s main claim to fame is its high nutrient content. This is especially true regarding protein—eggs pack a mighty punch. One large egg—the standard in the United States—contains 6 to 8 grams of protein.2,7 Compare this to a half cup of cottage cheese (12g protein) or two tbss of peanut butter (7g protein).8 While the protein found in eggs is distributed equally between the egg white and egg yolk, other nutrients are mostly concentrated in the yolk.6 Eggs also are a good source of lipids, vitamins, and minerals. In fact, the yolk contains all vitamins except for vitamin C, as well as all essential trace elements, including copper, iron, magnesium, manganese, selenium, and zinc.6

Egg yolks are notoriously high in cholesterol. A typical large raw egg contains 186 milligrams (mg) of cholesterol. Health experts suggest limiting intake of dietary cholesterol—ideally keeping it under 300mg a day.9 This doesn’t mean you have to pump the brakes on eating eggs though. While some studies suggest a link between egg consumption and CVD, it could be due to several other factors.10 Other breakfast foods, such as bacon, sausage, ham, and cheese, may pose more risk than eggs for CVD. This apparent relationship could also be attributed to the ways that eggs are prepared. For example, eggs fried in oil or butter could play more of a role in the increased risk of heart disease than eggs by themselves. When looking at studies that examine the relationship between egg consumption and heart disease, it is important to keep the golden rule of research in mind: correlation does not always equal causation.

Benefits of Eggs

Moderate calorie source, high satiety. Depending on its size, one egg provides 50 to 90 calories.11 This is a moderate number of calories when compared to other foods of a similar size. The real value, however, is its high satiety effect, or the absence of hunger after eating.12 Egg protein, which prompts significant changes in satiety hormones, has significant effect on hunger.1,12,13 For example, several studies have shown reduced caloric intake after an egg breakfast compared to a bagel breakfast.12 This may promote weight loss in those seeking to reduce their weight. People who eat eggs feel fuller and are less likely to eat more during or immediately after the meal.

Low economic cost, better accessibility. Eggs are one of the most widely available and economical sources of animal protein worldwide.1 About 12 percent of Americans are food insecure, which has been linked to a multitude of negative health outcomes. Across the globe, this figure increases to 30 percent, a value that has been steadily increasing.14 Eggs are cost efficient. When comparing the relationship between foods based on calories and unit cost, the energy cost of eggs is less than that of other animal-protein foods, such as meat, poultry, and fish.15 This is why egg consumption may be a valid dietary staple for food-insecure families, especially those challenged by limited nutritional intake.

Improves “good” cholesterol. There are two types of cholesterol: high-density lipoprotein (HDL)—or “good” cholesterol—and low-density lipoprotein (LDL)—or “bad” cholesterol.16 LDL contributes to fatty buildups in arteries, which narrows them, increasing the risk for heart attack, stroke, and peripheral artery disease.17 HDL, on the other hand, carries “bad cholesterol” away from the arteries and back toward the liver where LDL is broken down. This is one reason why eggs have been found to have little to no effect on heart disease risk.18-20 Notably, HDL cholesterol doesn’t completely eliminate LDL cholesterol. Only one-third to one-fourth of blood cholesterol is carried away by HDL.17

Good for eye health.  Eggs are highly bioavailable sources of lutein and zeaxanthin (L/Z)—antioxidants that can reduce the risk of certain eye diseases—which means that these nutrients in egg form are better absorbed by the body than from alternate sources. L/Z accumulate in the retina of the eye and help form the retinal macular pigment (MP), which can help improve visual performance and protect the eyes against the damaging effects of light.21 Notably, L/Z can prevent age-related macular degeneration (AMD), a leading cause of blindness in the developed world that is expected to increase in the coming years.21

Food Safety and Storing Eggs

Fresh eggs, even those with clean uncracked shells, may contain Salmonella, which can cause foodborne illness.2 A contaminated hen can transmit Salmonella inside the egg if the shell has not completely formed, but the bacteria can also penetrate eggshells, which have tiny open pores.4 The United Stats Food and Drug Administration (FDA) has implemented many safeguards to prevent contamination during farming, shipping, and storing of eggs, but the consumer also has a role in protecting themselves against egg-related illness. The FDA provides the following safety tips on buying, storing, preparing, and serving eggs.24

Buying. For consumers, egg safety starts at the grocery store. When browsing the dairy section, make sure to buy eggs that are refrigerated at a temperature of 40° F or below. Grocery stores often have a thermometer inside refrigerated areas. Do not buy eggs that are cracked.

Storing. Raw. Proper storage of eggs can affect both their quality and safety. If eggs crack on the way home from the store, break them into a clean container, cover tightly, keep refrigerated, and use within two days.24 Do not put broken eggshells back in the carton.25 Due to how easily eggs can become contaminated, the cartons can quickly become a reservoir for bacteria. Make sure to store eggs in the coolest part of the refrigerator. Placing them inside the doors’ shelves makes them vulnerable to varying temperatures and can also put them at a higher risk of falling and cracking.

Eggs can be frozen for up to one month, but they should never be frozen in their shells.24 Instead, beat yolks and whites together; egg whites can also be frozen by themselves.

Cooked. If storing hard-boiled eggs, be sure to consume them within one week. The same rule applies if they are still in the shell or peeled.

Preparing. Wash hands, utensils, equipment, and work surfaces with hot, soapy water before and after contact with raw eggs or raw egg-containing foods.25 To ensure eggs have even heat distribution, cook them slowly over gentle heat. Eggs should be cooked until both the yolk and the white are firm. Foods that contain eggs, such as casseroles, quiches, soufflés, and baked goods, should be cooked until the internal temperature reaches at least 160º F.4,26 If a recipe calls for raw or undercooked eggs, such as Caesar salad dressing, homemade ice cream, or homemade mayonnaise, only use eggs that have been treated to destroy Salmonella by pasteurization or another approved method.

Serving. Serve cooked eggs and egg-containing foods immediately after cooking. If you choose to refrigerate these products, they should be thoroughly reheated to at least 165° F before serving. Eggs should never be out of the refrigerator for more than 2 hours or for more than 1 hour when temperatures are above 90° F.25

Bottom Line

Whether they’re fried, poached, scrambled, or boiled, eggs can be a tasty, versatile protein choice. They are rich in vitamins and nutrients and have numerous benefits for your health. Like all foods, however, moderation is key. People with a high risk for CVD should be mindful of their egg consumption and search for other plant-based protein options. Make sure you buy, transport, and store your eggs properly. 


Editor’s Note

Consult with a licensed nutritionist/ dietitian or qualified healthcare professional to discuss what, if any, dietary modifications, including the addition of eggs, are right for you.


Sources

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