Eggs are the perfect foods that are delicious, high in quality protein, and packed with micronutrients. They are easy to cook, affordable, and great for the human body. Known as the “nature’s vitamin”, eggs can be the perfect way to start your day.
The low carbohydrate content of the egg makes it the number one choice of not only healthy, young adults but also people with diabetes.
However, the way eggs are cooked directly affects their nutrient availability. Like all other foods, eggs also need to be cooked such that the harmful bacteria are killed, but most of its nutrients are preserved.
In this article, we will evaluate the healthiest methods of egg consumption and examine how different cooking methods affect the nutrient value of eggs.
Egg Nutrition
If there was a competition over perfect foods, eggs would have been its best contender. Eggs have everything that is good for our health.
They have very high-quality protein, low amounts of carbohydrate, moderate amounts of good fat, high amounts of vitamins and minerals, as well as plenty of antioxidants.
Eggs contain all the 9 essential amino acids, making them a complete protein source. In addition to the protein in the eggs, other vital nutrients such as Vitamin D, calcium, potassium, phosphorus, and magnesium help build our muscles and strengthen our bones.
It’s iron and folic acid content help in carrying oxygen throughout our body and for maintaining healthy cells. The high amount of B-vitamins in the eggs boosts energy and metabolism.
Choline is a vitamin that helps improve brain function. Selenium and Vitamin E present in eggs work as an antioxidant and protect the body from harmful effects of free radicals.
The two carotenoids, lutein, and zeaxanthin found in eggs help improve vision.
A large-sized boiled egg (50g) contains: (1)
- Calories: 78
- Protein: 6.29g
- Fat: 5.3g
- Carbohydrate: 0.56g
Summary: Eggs are highly nutritious, containing all 9 essential amino acids, good fats, vitamins, minerals, and antioxidants.
The Pros and Cons of Cooking Eggs
Eggs are delicious and can be incorporated into our diet in a variety of ways. Some people prefer eating them raw and some prefer them cooked.
Eggs can be cooked on their own in different ways, as well as can be combined with other foods.
Heat ensures a safer egg and enables certain nutrients to be broken into a simpler form rendering it readily digestible.
But, it is also known that heat destroys some of the antioxidants in eggs and oxidizes the cholesterol in the yolk.
So, let’s take a detailed look at them and understand the science behind it.
The 3 Advantages of Heating Eggs
Cooking Makes Some Nutrients Digestible
Both egg white and egg yolk are great sources of protein. But, some of them are indigestible, making them unavailable to the human body.
Raw eggs contain large-sized protein compounds that are curled up in a contorted manner. Our body can’t digest it. But, when the egg is cooked, heat breaks them and forms new bonds. These new bonds in the cooked egg are easier for the body to digest. Hence, heat makes them accessible to you.
One study found that the human body can use 91% of the protein in cooked eggs compared to 51% in raw eggs (2).
Cooking Improves Bioavailability of Nutrients
Avidin, a protein, present in raw eggs can interfere with the absorption of a micronutrient called ‘biotin’. Also known as vitamin B7 or vitamin H, biotin is extremely crucial in fat and sugar metabolism in the human body.
But, avidin binds the biotin making it unavailable in raw eggs. Heat causes avidin to break down thus making the biotin available for absorption.
A clinical trial conducted by Evenepoel et al. and published in 1998 in the Journal of Nutrition observed that cooking eggs increased their digestibility.
The egg proteins became twice as usable by the body compared to raw eggs.
Cooking Can Make The Eggs Much Safer To Eat
Eggs are one of nature’s nutritious food and are prone to be infested with microorganisms such as bacteria.
Eggs that appear safe to eat may contain bacteria known as Salmonella. It can make you sick. As heat can kill this microbe, cooked eggs are safe but it is not the case with raw eggs.
Salmonella can contaminate the egg even before the shells are formed. Aged people, small kids, and people with compromised immune systems can get seriously ill with Salmonella caused disease (3).
Summary: Cooking eggs makes them safe from bacteria like Salmonella and makes the nutrients more available for digestion and absorption.
3 Disadvantages of Heating Eggs
Heat Damages Certain Important Vitamins
Heat can damage many of the nutrients in eggs. Egg yolks do not react to the heat in the same manner as egg white. High heat damages the fat and many of the vital nutrients present in the yolk.
If eggs are cooked at high temperatures for a long period of time, a lot of vitamins in the egg yolk gets destroyed.
One study found that cooking eggs reduced vitamin A content by 17-20 % (4, 5). Research has also shown that, when eggs were baked for 40 minutes, they lost up to 61% of their vitamin D (6). Frying or boiling for a shorter duration reduced it by 18%.
Heat Damages Antioxidants Present In Eggs
Eggs are a rich source of antioxidants. Amongst them, xanthophyll, lutein, and zeaxanthin have shown a visible reduction in quantity when exposed to heat while cooking.
Xanthophyll is a pigment that is responsible for the yellow color of the egg yolk. It is a strong antioxidant and has numerous health benefits. Lutein and zeaxanthin, are two carotenoids that play a crucial role in the prevention of age-related macular degeneration.
In 2016, a randomized controlled trial observed that one egg per day increases the serum lutein and zeaxanthin without altering the serum lipid (7).
But, during the cooking of egg, heat reduced the lutein and zeaxanthin. Boiling, microwaving, and frying of eggs reduced the lutein content by 23%, 17%, and 19%. The xanthophyll loss ranged from 6-18% (8).
The loss is mostly due to oxidation and degradation (9).
Heat Results In Oxidation of Cholesterol Which Can be Harmful
Egg yolks are high in cholesterol and contain around 212 mg. This is nearly 71 % of the previously recommended intake of cholesterol of 300 mg per day. Now, there is no upper limit of cholesterol.
Studies have shown that this cholesterol is not as evil as it is painted to be. When you provide cholesterol to the body through diet, the liver simply reduces its cholesterol production and uses this one for the different functions in the body.
However, when eggs are cooked at high temperatures, the cholesterol in the yolk is oxidized, producing a compound called oxysterols (10).
These oxysterols are thought to impact the creation of atherosclerotic lesions (11, 12, 13). However, the oxidized cholesterol present in food is less harmful than the cholesterol that is oxidized in the body.
Summary: The heat damages the antioxidants and vitamins in the egg. The cholesterol present in eggs gets oxidized with heat and produces compounds that are harmful to the body.
Egg Yolk vs Whites
Eggs are a great source of complete protein and have very few calories (14). The protein concentration is near about 12.5 g per 100 g of whole raw fresh egg. It is an excellent source of a very important nutrient known as choline.
Choline helps in increasing the bioavailability of folic acid. But, the high cholesterol content of egg yolk, has been a matter of concern and full of controversies.
That brings the question in mind “what is better, the egg white or egg yolk?”
The Egg Whites
Egg whites are fat-free and low in calories. The bulk of the protein, present in the egg, is in the egg white.
Egg white contains a significant amount of B1, B6, B8, B9, and B12. Eating two eggs per day covers 10% to 30% of the vitamin requirement for humans.
The Egg Yolks
Egg yolk on the other hand is packed with fat-soluble vitamins, essential fatty acids, and minerals. It is a vitamin-rich food that contains all vitamins except vitamin C. It has a high amount of vitamin A, D, E, K, B1, B2, B5, B6, B9, and B12.
Eggs also represent a major source of choline, which is essentially concentrated in the yolk. It is crucial in neurotransmission, brain development, and bone integrity. Egg yolk is also a major contributor of iron and zinc.
As it is understandable, that egg yolk has more nutrients than egg white, but the presence of a high amount of cholesterol (212mg) does give it a negative name (15).
New research shows that, contrary to previous belief, moderate consumption of egg doesn’t increase the risk of heart disease, and the entire egg eaten as a whole, gives the most complete nutrition. Nature has married the yolk and white, and together they give the most complete nutrition.
Studies not only confirmed that 7 eggs per week are absolutely safe (16, 17). But also suggested that they prevent certain types of stroke and eye conditions. So, the amount of eggs you eat is not necessarily a concern.
( Note: People with established cardiac problems should take their doctor’s advice.)
Summary: Egg whites are fat-free, less in carbs, and excellent sources of high-quality protein and minerals. Egg yolk is packed with vitamins, essential fatty acids, minerals, and antioxidants. Even though the cholesterol in egg yolk gives it a bad reputation, eating egg as a whole provides you with the utmost nutrients.
The Pros And Cons of Eating Raw Eggs
Sylvester Stalone, guzzling down a tall glass of raw eggs in the morning to build muscles is a classic scene that became the norm from the legendary movie “Rocky”, which hit the theatres in 1976.
Raw eggs became the new trend as the bodybuilder’s breakfast. Many who wanted to build muscles were found gulping down raw eggs before their workouts.
Then in 2010, came the scare of Salmonella associated with raw eggs. Half a billion eggs were recalled due to the outbreak. Strict guidelines to store and cook eggs were given (18).
Hence, ‘raw egg or cooked egg?’ which is better became a common question.
Here are jotted down some of the pros and cons of consuming raw eggs:
Pros:
- Raw eggs are highly nutritious as the vitamins and antioxidants are intact
- Raw eggs do not have any danger of cholesterol oxidation
Cons:
- Raw eggs contain a protein “avidin”, that binds the vitamin biotin leading to its deficiency
- It can be exposed to Salmonella and when eaten can cause serious health issues
So, as with most foods, the best way to consume an egg is to cook it long enough in order to kill harmful bacteria while not overcooking them to the point of damaging the nutrients it contains.
Summary: Even though consuming raw eggs ensures all the nutrients, it is safer to cook the egg and consume it. Just a little heat to make the protein more digestible and avert Salmonella infestation. But, not so much to destroy the nutrients.
The Best to the Worst: Different ways of Eating and Cooking Eggs
Eggs are an absolutely delicious addition to any food. It can be cooked in different ways. It is easy to combine with other healthy foods like whole grains and vegetables. Even though heat does reduce the nutrients to some extent, it is still one of the most nutritious foods (19).
Here are some of the popular cooking methods of eggs:
Soft Boiled Eggs
They are one of the best ways to cook eggs. In this procedure, the egg is boiled, but still left a little bit runny and the yolk is not hard.
Soft boiled eggs are the healthiest of all other cooking versions and tasty as much. This cooking method is also the lowest heat method.
In a soft-boiled-egg, the fats and nutrients of the yolk have three protective layers – the water, the eggshell, and the egg white, that prevents its oxidation.
In this process, the egg whites are cooked enough for the best protein utilization and removal of avidin and the good stuff in the egg yolk is maximally preserved.
Poached Eggs
The next in line in terms of healthy egg cooking is poached eggs. They are cracked into a pot of simmering water between 160-180° F and cooked for 2.5-3 minutes.
Here, while the egg yolk remains submerged in water and covered mostly by the egg white, the protective shell layer is lost. Check out the video of Jamie Oliver teaching the right way to make poached eggs.
The dish that is most commonly associated with poached eggs is egg-benedict. However, it can be served without hollandaise.
Hard-Boiled Eggs
Hard-boiled eggs are cooked eggs, which are cooked in their shells in a pot of boiling water for about 6-10 minutes, depending upon how well you want it to be cooked.
The longer you cook, the firmer is the yolk. Even though it doesn’t contain maximal nutrition, it still is healthy.
Even though it retains the three layers intact, the yolk reaches a higher temperature and the destructive process starts. But, as the egg yolk is not exposed to oxygen, it is limited.
Sunny-Side Up
In this type of cooking process, all the direct cooking is at the bottom of the egg and the yolk stays fairly preserved. However, the protective water coating is lost making the above-mentioned processes much more preferable.
The best way to cook a Sunnyside up is with the lowest possible heat. The lower the heat, the lesser is the oxidation of fats and healthier is the egg.
Also known as the ‘emoji egg’, check out this quick video on how to make it.
Over-Easy Eggs
This is the same as Sunnyside up, but the egg is effectively exposed to heat and oxygen on both sides.
As the yolk is directly exposed to high heat on both sides, there is an increased loss of precious nutrients in the egg yolk and making the fat less beneficial.
Baked Eggs
Baked eggs are considered nutritious and very easy to prepare. Any choice of toppings or mix-in can be served with it. Just how nutritious they will depend on your preparation. Simply baking them in a muffin tin is similar to the over-easy eggs as the whites and yolks are exposed to heat from both sides.
Preheat the oven to 350° F. On a muffin pan, add a bit of cooking spray, crack the eggs and put in a muffin tin. Bake the eggs for 14-18 minutes or until the whites are fully cooked and the yolks are to your likings.
Other baked versions of eggs that include a base made of another ingredient and a topping that helps enclose the egg inside, helps ensure the yolk is not exposed to oxygen during the cooking process, thus maintaining its high nutrient values.
Scrambled Eggs
Scrambling the eggs is essentially mixing up the fats and the proteins and directly exposing them to heat and oxygenation over and over.
It is the worst way to eat eggs, because this process involves more opportunity to oxidize fats and cholesterol, making them potentially detrimental to health (20).
Omelets are similar to scrambled eggs and may or may not be mixed with vegetables and herbs. The same exposure to heat and oxygen is there, making this process also not a convenient choice.
Microwaved Eggs
Microwaving eggs are a great way to preserve egg nutrition. You can put the eggs in a bowl of water and cover them before putting them in the microwave. Whole eggs are usually microwaved for 4 to 5 minutes at 50% power.
But beware that the egg might just explode inside your microwave if you don’t prick it first with a safety pin or thumbtack.
There are other ways to cook eggs in a microwave and how healthy they are will be based on how much you expose the yolk to the heat and oxygen as well as how long you cook it.
Summary: The poached, soft boil and hard-boiled eggs are extremely nutritious as it averts the breakage of the protective layers over the yolks. These cooking methods maintain most of the nutrients and does not allow the egg yolk to oxidize.
5 Tips To Cook Super-healthy Eggs
Eggs are nutritious, but believe it or not, can be made even healthier.
Below are five tips to cook super healthy eggs:
1. Choose the most nutritious eggs you can afford- Organic, free-range, omega-3 enriched, etc.
2. Choose a low-calorie cooking method to reduce your overall calorie intake. A tablespoon of butter has 102 calories while a large-sized egg (50gms) has just 78 calories. So boiled eggs have a much lower calorie option compared to fried or scrambled eggs.
3. Combine them with vegetables to increase the nutritional value of your meals.
4. If you are using any type of oil to cook or scramble them, make sure to use one that is stable in high temperatures.
5. Don’t overcook them as this helps preserve the nutrients in the egg and it tastes better too.
The Final Note
If you are not allergic to eggs, then eggs can be a great addition to your diet.
Eating raw eggs ensures all the egg nutrients. But, it may not be safe. The fear of Salmonella infestation is always there.
Shorter and lower heat methods for cooking eggs are the best as they cause little or no cholesterol oxidation. Such cooking methods also help retain most of the nutrients.
Poached and soft-boiled eggs are the healthiest followed by hard-boiled eggs. They also don’t use unnecessary calories for cooking (21).
Having 1 to 3 eggs daily makes it much easier to meet our daily nutritional requirements. Even diabetics can have one egg a day safely.
