Are Eggs Healthy: What Does the Science Say?

For many years (decades, actually) there has been an ongoing debate about eggs. One minute we’re told by the media that eggs -- especially the yolks -- should be avoided at all costs since they contain cholesterol. Next thing you know, they are back in favor. 

With low carbohydrate diets such as the keto diet on the rise, eggs are becoming more and more popular. They’re a great source of protein and healthy fat, and they also contain a wide array of essential nutrients -- some of which are hard to find in other foods.

The confusion about eggs all stems from the amount of cholesterol they contain.⁽¹⁾ A single egg contains over 200 milligrams of cholesterol, and the American Heart Association recommends consumption of no more than 300 milligrams per day. 

While there has definitely been concern over the years that the cholesterol in eggs may raise your blood cholesterol and increase the risk of heart disease, this is simply not supported by current research. Contrary to popular belief, dietary cholesterol does not appear to have that much impact on blood cholesterol. 

In this article, we will look at what modern science says regarding egg consumption, as well as some of the benefits of eating eggs. We’ll also examine the different types of eggs that are now commonly available in supermarkets, explaining terms like pastured, organic and omega-3. By the end of this article, you’ll be able to make an informed decision about including eggs in your diet.

Are Eggs Healthy: What Does the Science Say?

Numerous studies, involving thousands of participants of all ages, have been conducted on egg consumption. Some trials were short term, some longer-term. To date, researchers have failed to find any association between egg consumption and cardiovascular disease.

For example, A fourteen-week study divided healthy college students into two groups. One of the groups consumed two eggs for breakfast five days per week.⁽²⁾ The second group was told to avoid eggs completely.  Other than that, both groups could eat anything they wanted. At the end of the study, both groups had gained weight (pretty common with college students) but there were no significant differences in lipid profiles, between the two groups.

Another twelve-week study was performed on overweight diabetics.⁽³⁾ They were split into two groups. One group consumed no eggs at all, and the other group consumed two eggs daily. At the end of the twelve weeks, both groups saw an equal decrease in total and low-density lipoprotein (LDL) cholesterol. 

On top of that, The egg consuming group also saw a greater increase in beneficial high-density lipoprotein (HDL), so there was actually a benefit to consuming eggs.   

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Observational studies have also shown the same type of results. Studies involving both Japanese subjects, as well as, those following a Mediterranean diet ultimately found no association between regular egg consumption and risk of cardiovascular problems.⁽⁴⁾

Another observational study showed that consuming one to six eggs per week did not increase risk of stroke or coronary artery disease. Consuming more than six eggs per week, on the other hand, increased the risk of coronary artery disease in subjects that were already diabetic.

It should be noted, however, that while the above observational study suggests an increased risk of heart disease in diabetics with higher egg consumption, other controlled trials failed to find any such association.

 For example, 140 diabetics and pre-diabetics were studied for three months.  They were randomly assigned to eat two eggs at least six times a week, or less than two eggs per week.  No significant difference was found in HDL, LDL, triglycerides, or glycemic control.

Benefits of Eating Eggs

Now that research has shown us that there's no reason to fear eggs, let’s take a look at some of the benefits associated with egg consumption.

1. They’re a High-Quality Protein Source

Eggs are an excellent source of protein.  They’re also readily available, extremely versatile, and reasonably priced, especially compared to many other protein sources.  A large egg white contains 3.6 grams of protein, with the yolk containing 2.7. 

Egg protein contains all nine essential amino acids and has a high biological value, meaning it’s easy for the human body to absorb.⁽⁵⁾ Typically, animal sources of protein, such as eggs, fish, and meat, have higher biological values than plant-based sources of protein.

2. Eggs are Loaded With Essential Micronutrients

In addition to being an excellent source of protein, eggs are also loaded with micronutrients -- they contain a variety of different essential vitamins and minerals, which is why some people refer to them as a “superfood.”

They actually contain small amounts of just about every vitamin and mineral required by the human body, including B vitamins, calcium, iron, potassium, zinc, manganese, and vitamin E. 

Eggs also contain the fat-soluble vitamins A and D, both of which are essential for skin health. The one nutrient they do lack is vitamin C.

 It should be noted that the vitamins and minerals are all concentrated in the yolk.  In addition to the nutrients listed above, eggs are loaded with the carotenoids lutein and zeaxanthin, which are known for having many health benefits, although they are best known for protecting the eyes and reducing the risk of macular degeneration.

Eggs are also an excellent source of choline, which is a micronutrient necessary for healthy brain development, liver function, the nervous system, and metabolism.⁽⁶⁾ One large egg contains around 150 milligrams of choline. It is recommended that an adult male consume 550 milligrams of choline daily, and a woman 425 milligrams. Pregnant and breastfeeding women require higher amounts of 450 milligrams and 550 milligrams, respectively.

 Since a typical serving of eggs is two or three, it is easy to see how they can help you meet the daily requirement for choline. Other dietary sources of choline include beef liver and fish -- eggs are definitely a more palatable choice than liver (at least for most of us!)

3. They Help With Cholesterol Homeostasis

Eggs were vilified for many years due to their high cholesterol content, although it is now known that dietary cholesterol does not actually have much of an impact on levels of cholesterol in the blood. 

In fact, eggs may actually help with certain aspects of your cholesterol.  In addition to improving your HDL cholesterol levels, eggs may also help with cholesterol homeostasis.  Research shows that the phospholipids in eggs help in regulating the absorption and metabolism of cholesterol in the body.⁽⁷⁾

4. Eggs are Easy to Make and There's a lot of Variations

From poached to over easy, there are many different ways to prepare eggs.   In order to obtain maximum health benefits from eggs though, it is important that the white is cooked thoroughly. 

Uncooked egg whites contain avidin, an anti-nutrient that binds to biotin and some other B vitamins, preventing them from being absorbed. In addition, many experts recommend that eggs be thoroughly cooked, to reduce the risk of contracting the salmonella virus. 

Are Some Types of Eggs Better Than Others?

It used to be that when you walked into a supermarket the only decision to be made about eggs was the size. You could get medium, large, or extra-large. Now there is a multitude of choices -- there’s omega-3-enriched eggs, cage-free eggs, pastured eggs, organic eggs, and so on -- and it may have you wondering if there’s really any difference. 

⫸Conventional Eggs

Conventional eggs are raised on factory farms, where the chickens are tightly packed into small enclosures. Not only is there no access to the outdoors, but there’s also barely any room to move. The term cage-free simply means the chickens are not in cages. 

They can still be packed into a henhouse, but typically have some access to the outdoors (even if it is just a concrete slab). Cage-free eggs are not nutritionally superior to conventional eggs unless the feed has been enriched in some way.

⫸Omega-3-Enriched Eggs

If the eggs are omega-3-enriched, the chicken feed has been enriched with an omega-3 source, which is flaxseed in most cases -- flax seed is high in ALA (alpha linoleum acid).(8) 

 In some cases, the chicken feed is also enriched with fish oil, which is higher in the omega-3 fatty acid DHA (docosahexaenoic acid.) Some consumers complain of a slight fishy taste and smell when the chickens have been fed the fish oil enriched feed.  In either case, the eggs will be higher in omega-3s, when compared with conventional eggs. They will carry a higher price tag, as well.

⫸Pasteurized Eggs

If the package says pastured eggs, the chickens have access to pasture where they can peck around in the dirt and eat plants and bugs. They are still given commercial feed to supplement what they are picking up, in the great outdoors. 

Pastured eggs are higher in vitamins A and E, as well as omega-3 fatty acids. They are also lower in cholesterol. Many people also like the idea of the chickens having better living conditions, and some prefer the taste, though you will pay a premium for pastured eggs.

⫸Organic Eggs

If the eggs carry an organic label, it means they were fed organic feed that does not contain any genetically modified organisms. These chickens typically have access to pasture as well, so they will also be more nutritious than conventional eggs. 

Not surprisingly, organic eggs will cost more. In fact, organic pastured eggs are typically the most expensive eggs in the supermarket. Even the highest-priced eggs are still a reasonably priced source of protein, so paying more for “designer” eggs, is not necessarily a bad idea.

Wrap Up

Science shows that eggs can definitely be part of a healthy diet; researchers have found no association between egg consumption and cardiovascular disease.

Eggs contain a wide array of essential nutrients. Not only that, they are versatile and affordable – especially when compared with other clean sources of high-quality protein.

• References
  1. “Dietary Cholesterol, Serum Lipids, and Heart Disease: Are Eggs Working for or Against You?”N. Blesso, C.N., Fernandez, M.L. Nutrients. Mar. 2018.
  2. “Egg and Egg-Derived Foods: Effects on Human Health and Use as Functional Foods”Miranda, J.M., Anton, X., Redondo-Valbuena, C., Roco-Saavedra, P., Rodriguez, J.A., Lamas, A., Franco, C.M., Cepeda, A. Nutrients. Jan. 2015.
  3. “Egg and Egg-Derived Foods: Effects on Human Health and Use as Functional Foods”Miranda, J.M., Anton, X., Redondo-Valbuena, C., Roco-Saavedra, P., Rodriguez, J.A., Lamas, A., Franco, C.M., Cepeda, A. Nutrients. Jan. 2015.
  4. “Cholesterol and egg intakes and the risk of type 2 diabetes: the Japan Public Health Center-based Prospective Study.”Kurotani, K., Nanri, A., Goto, A., Mizoue, T., Noda, M., Oba. S., Sawada, N., Tsugane, S. British Journal of Nutrition. Nov. 2014.
  5. “Egg and Egg-Derived Foods: Effects on Human Health and Use as Functional Foods”Miranda, J.M., Anton, X., Redondo-Valbuena, C., Roco-Saavedra, P., Rodriguez, J.A., Lamas, A., Franco, C.M., Cepeda, A. Nutrients. Jan. 2015.
  6. “Concentrations of choline-containing compounds and betaine in common foods.”Zeisel, S.H., Mar, M.H., Howe, J.C., Holden, J.M. Journal of Nutrition. May. 2003.
  7. “The Impact of Egg Nutrient Composition and Its Consumption on Cholesterol Homeostasis”Kuang, H., Yang, F., Zhang, Y., Wang, T., Chen, G. Cholesterol. Aug. 2018.
  8. “Enhanced Egg Production in Practice: The Case of Bio-Omega-3 Egg”Yannakopoulos, A., Tserveni-Gousi, A., Christaki, E. International Journal of Poultry Science. Aug. 2005.