Healthy or Not? Unlocking the Secrets of Eggs

By Claire Carlton, MS, RD, LD/N

For a long time, this versatile, budget-friendly food was vilified in the health and nutrition world due to its high cholesterol levels. Some may remember the iconic Time magazine cover from 1984 picturing a plate of eggs and bacon frowning. Consumers obediently began choosing egg whites and imitation egg products hoping to reap the high protein benefits of eggs without any fat or cholesterol. Foods such as Egg Beaters showed up on the breakfast scene. Essentially, these products processed eggs and stripped them of their yolks, along with many of their powerful nutritional benefits. However, the all-mighty egg, in its simple and edible package, is chockfull of nutrients.


Yes, it is true that eggs contain a significant amount of cholesterol. For many years, we were told to limit our daily intake of cholesterol to less than 300 mg/day for heart health because conventional wisdom led us to believe that cholesterol from foods led to atherosclerosis (clogged arteries). Research from the Department of Agriculture shows that dietary cholesterol, meaning the cholesterol we obtain through consumption of certain animal foods, has very little, if any effect on our serum (blood) cholesterol levels. In fact, the new Dietary Guidelines for Americans 2015–2020 from the Department of Health and Human Services and the USDA have removed this recommendation, claiming that there is not adequate evidence to support a specific limit on dietary cholesterol. The DGA further states that cholesterol is not a nutrient of concern for overconsumption.


Eggs are a great source of vitamins A, D, E and several B vitamins. Vitamin A plays a role in eye health and immune function. Vitamin E serves as an antioxidant in the body to prevent cells from damage. B vitamins are crucial for energy metabolism among many other functions. Vitamin D is essential for bone health and also plays a role in immunity and depression. Yolks are rich in choline, a nutrient considered to be a vitamin-like compound, which plays a role in fat metabolism and cholesterol transport. In addition, choline is important for the structural integrity of cell membranes. Also important is choline’s role in the production of the neurotransmitter acetylcholine, which is important for muscle movement and memory. To reap these benefits, you must eat the yolks!


Eggs also boast an impressive list of minerals, including iron, selenium, zinc and phosphorous. Iron is necessary for oxygen transport in the body. Selenium acts as an antioxidant, protecting cells from free radical damage among many other functions. Zinc is crucial for wound healing and plays a role in normal growth and development during pregnancy and childhood.


As a complete protein, eggs contain all the essential amino acids our bodies require to carry out functions such as muscle and tissue growth and repair, as well as production of neurotransmitters. Eggs are known to have high biological value protein, which means that our bodies digest, absorb and utilize the protein extremely efficiently. It is a myth that all of the protein in eggs is found in the white. A look at the USDA nutrient database confirms that while the white does contain a larger percent of the total protein found in eggs (58 percent), the yolk still contains 31 percent, with the shell containing the final 11 percent (I don’t recommend eating the shell!). Each egg contains 6 grams of protein to support a healthy body!

Clearing the confusion: Interpreting supermarket labeling

Omeg- 3 Enriched – Eggs boasting this claim usually come from hens whose feed has been enhanced with flax seed and/or fish oil. Flax is more popular in order to avoid a “fishy” tasting egg. Expect to pay a higher price for these “designer” eggs.

Cage Free – Cage free doesn’t necessarily mean the chickens are roaming the farm. In fact, these chickens often live among thousands inside a large barn with no access to outdoor space. When a consumer sees “Cage Free,” sunny pastures may come to mind. Don’t be fooled.

USDA Organic – This is the most regulated claim you will find on an egg carton. Organic eggs come from hens that exclusively consume organic feed (free of pesticides and fertilizers) and are also allowed access to the outdoors and sunlight. Regular inspections take place to ensure these standards are followed.

Pasture Raised – This label is not regulated by the USDA. Many farmers and producers, such as Vital Farms Eggs, indicate that hens have access to pasture in order to consume their natural diet. With access to pasture, the yolks may contain more heart healthy omega-3 fats. Expect to pay more.

Vegetarian Fed Hens – Hens consume feed free of animal byproducts — usually the feed consists of grain, seed and soy. It is important to note that chickens are NOT vegetarians. This is a buzzword companies use to charge more for eggs. Left to forage in their natural living conditions, chickens would consume a variety of worms, bugs and plants.

When considering which eggs to buy, nutritional differences are quite minimal. I often recommend people learn about the above labeling claims and choose based on personal needs and values such as budget, environment and animal welfare.

What about the color?

Brown, white, blue, green — eggs come in a variety of different colors. There is no difference in nutritional value between the colors; it simply indicates the breed of the hen.

Bodybuilders beware!

Raw egg whites contain a protein called avidin, which binds to the B vitamin, biotin. Heavy consumption of raw egg whites can cause biotin deficiency! Cooking your eggs will denature this protein while also reducing your risk of foodborne illness.


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