Whether it's a quail egg, chicken egg or duck egg, you can hard-boil just about any type of egg and turn it into a tasty snack. Eggs are healthy because they are filled with beneficial vitamins and minerals, while simultaneously being low in calories and carbohydrates. Hard-boiling eggs means that they'll be cooked thoroughly and have less of a chance of retaining disease-causing bacteria. However, their nutritional value can change, depending on how much heat is applied to them.
Hard-Boiled Egg Nutrition Facts
Eggs are healthy, nutrient-rich foods. A large hard-boiled egg has 77.5 calories, with almost none of these calories in the form of carbohydrates, because there are few carbs in a boiled egg. Each large, hard-boiled egg contains:
- 13 percent of the recommended daily value of protein
- six percent of the recommended daily value of vitamin A
- 15 percent of the recommended daily value of vitamin B2 (riboflavin)
- 7 percent of the recommended daily value of vitamin B5 (pantothenic acid)
- 5 percent of the recommended daily value of vitamin B9 (folate)
- 9 percent of the recommended daily value of phosphorus
- 22 percent of the recommended daily value of selenium
Each large hard-boiled egg also has 1 to 4 percent of various other vitamins and minerals, including other B-complex vitamins, vitamin E, calcium, iron, magnesium, manganese, sodium and zinc. Some eggs may even be enriched with healthy fatty acids, known as polyunsaturated fatty acids. These are omega fatty acids like omega-3 and omega-6, which can also be found in foods like fatty fish and walnuts.
Heat is known to affect foods in different ways and has the potential to degrade beneficial nutrients. Hard-boiling eggs doesn't affect their nutrition too much. Most of the vitamins and minerals are almost the same in hard-boiled eggs and raw eggs. However, there are other nutrients found in eggs that do change during the cooking process.
Lutein and zeaxanthin, which are nutrients beneficial for your eyes, can be found in egg yolk. Boiling your eggs reduces the amounts of these nutrients, particularly that of zeaxanthin. Because heat, specifically cooking eggs all the way through, affects hard-boiled egg nutrition, soft-boiled eggs could be considered to be a bit better for you than hard-boiled eggs.
Soft-boiled eggs are easier for your body to digest compared to hard-boiled eggs and are more likely to retain the complete range of beneficial nutrients. However, cooking eggs can actually improve digestibility for people with egg intolerances or allergies.
Cooking Hard-Boiled Eggs
Preparing hard-boiled eggs can be a lot easier than cooking other types of eggs. To prepare hard-boiled eggs, place your eggs in a pot of cool water and bring the water to a boil. The water should cover the eggs fully so that once it's boiling, you can remove the pot from the heat and allow your eggs to rest in the hot water. As long as you keep the eggs in a covered pot, they should cook just by sitting in the water.
After five to 10 minutes (depending on the size of your eggs), your eggs will be ready to eat. Keep in mind that removing your eggs too early means that they're soft-boiled, while leaving them in too long will mean that they may become overcooked.
If you get the balance right, though, you'll have hard-boiled eggs that are easy to eat on the go as snacks or can be cooled, chopped up and integrated into a variety of other foods. Hard-boiled eggs can be used in salads, sandwiches, pizzas or as stand-alone foods, like when you make deviled eggs.
Overcooked and incorrectly cooked hard-boiled eggs have discolored yolks that are greenish-gray. This discoloration is caused by an interaction between the yolk and egg white during the heating process. Essentially, iron in the yolk and hydrogen sulfide in the egg white react to form iron sulfide. Overcooked hard-boiled eggs are safe to eat, but will taste far less pleasant and may have reduced nutritional value compared to those that have been properly cooked.
Hard-Boiled Eggs vs. Other Eggs
Hard-boiled eggs are one of the most popular ways to cook eggs in the United States, ranked only below omelets, fried eggs and scrambled eggs. Cooking your eggs in this way means that they are cooked all the way through, unlike many other cooking methods applied to eggs. This means that hard-boiled eggs are more likely to completely eliminate harmful bacteria, like Salmonella, which can often be found on eggshells or even within the eggs themselves.
The USDA Nutrition Database shows that there's not a huge amount of difference in the nutritional value of popular egg cooking methods, although digestibility can be affected. For instance, the main differences between scrambled eggs and hard-boiled eggs is that the protein in a hard-boiled egg is slightly higher, while calories are slightly lower.
Hard-boiled eggs benefit from not requiring any fats to be cooked, unlike scrambled or fried eggs, which are very often cooked with butter or other additional ingredients that increase fat content and calories. Since different cooking methods can impact the amount of proteins, healthy fatty acids and carotenoids in your eggs, it's a good idea to eat eggs that have been cooked in different ways.
The way you cook your eggs can also influence the amount of glycotoxins, also known as advanced glycation end products, that end up in the final food product. As their name implies, glycotoxins are not good for your health. They have been related to heart problems, inflammation and diabetes.
Glycotoxins occur in many foods, but are most present in high-heat, high-fat cooking methods. This means that frying eggs, which is the most popular cooking method, unfortunately also produces the most glycotoxins. In contrast, the low to medium heat used to cook scrambled eggs will have far less advanced glycation end products.
Read more: The 20 Best Ways to Use Eggs
Integrating Eggs Into Your Diet
Everyone knows that eggs can come in a variety of shapes and sizes. The United States Department of Agriculture says that chicken eggs typically range between 1.25 ounces for peewee eggs to 2.42 ounces for jumbo eggs. Despite the substantial range in size, large eggs are the size typically used in recipes.
Eggs contain cholesterol, which was once thought to contribute to diseases like heart disease. These days, the cholesterol in eggs is thought to be healthy, while the culprit was actually saturated fat. The Harvard T. L. Chan School of Public Health and the American Heart Association consider eggs to be a healthy food and even recommend a large egg a day as a perfectly healthy dietary choice.
Eating an egg a day may even be able to help reduce your risk of heart disease. The main thing you need to watch out for is what you're cooking your eggs with, as certain fats (like butter) do contain saturated fat that can increase your risk of certain diseases.
If you choose to consume more than an egg a day, that's OK too. A 2018 study in the American Journal of Clinical Nutrition showed that even people with prediabetes can consume up to 12 eggs per week without negative impacts to their health. You should always try to consume a balanced diet, but a few extra eggs every now and again won't negatively affect your health.
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