Eggs - an Indispensable Component of the Diet
Kacper Nowak
2026-03-18
4 min. read
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Eggs are an excellent source of nutrients, containing valuable vitamins, high-quality protein, and minerals. The chemical composition of eggs depends on many factors such as the feeding of chickens, genetic factors, and the age of the chickens. A raw egg consists of over 70% water. The energy value of an egg weighing about 50 g is 70 kcal. The protein content is about 6.2 g, the fat content is 4.8 g, the carbohydrate content is 0.3 g, and the cholesterol content is 186 mg.
Eggs as a protein supplier
Chicken eggs are a rich source of whole-value protein, which contains all of the exogenous amino acids that the human body cannot produce on its own but are necessary for optimal functioning. The proportions of these amino acids in eggs are so well-suited to human needs that they have been used as a reference standard for many years in assessing the biological value of other proteins. Consuming one egg covers approximately 25% of an adult's daily protein requirement.
Lipid substances are components of eggs, including triglycerides, phospholipids, cholesterol and free fatty acids.
The lipid substances present in eggs are triglycerides, phospholipids, cholesterol and free fatty acids. Triglycerides make up around 60%, phospholipids approximately 30%, cholesterol (both in free and esterified form) 6%, and free fatty acids about 1%.
Carbohydrate suppliers
Eggs do not constitute a substantial source of carbohydrate suppliers, providing merely 0.6 g of these compounds per 100 g of product.
Mineral compounds found in eggs
Eggs are a significant source of mineral nutrients such as zinc, phosphorus, and iron.. they contain naturally occurring selenium, which is a potent antioxidant and can inhibit the growth of prostate cancer.. the iodine present in eggs aids in normal thyroid function.. the eggshell contains large quantities of calcium, which is well absorbed by the human body.
Vitamins and their derivatives
Chicken eggs, particularly the yolks, constitute an exceptional source of nutrients, including the fat-soluble vitamins A, D, E, and K. Vitamin A is present in two forms - retinol and provitamin, i.e., beta-carotene. The former is characteristic of animal products, while the latter is more commonly found in plant products. It is important to note that vitamin D is rarely found in food products, but eggs are a good source of it. Among the water-soluble vitamins also present in eggs, mention should be made of the B-vitamins, including folic acid, choline, and niacin (which regulates glucose and cholesterol levels in the blood). Particularly significant is the presence of vitamin B12 in eggs, which is not commonly found in food products.
Bioactive compounds found in eggs
Discussing the role of eggs in nutrition, we cannot overlook the components that exhibit biological activity in supporting the body's defense processes. Among them are egg proteins containing lysosome, conalbumin, cysteine, folic acid, which act as virus and bacteria inhibitors. These proteins also protect the egg content from spoilage. Human consumption in the form of soft-boiled can fulfill these functions in the human body. We should also mention avidin, an egg protein that inactivates biotin in raw eggs, contributing to the development of harmful microorganisms. Thermal processing destroys the properties of avidin. Other bioactive compounds in eggs are carotenoid compounds - beta-carotene, cryptoxanthin, lutein, and zeaxanthin. Lutein and zeaxanthin are responsible for the proper functioning of the eyes and the prevention of age-related macular degeneration. Regular consumption of one egg per day significantly increases the lutein level in the blood. This does not negatively affect the cholesterol level, but it reduces the risk of cataract development. Choline, another bioactive substance in the egg, is a vitamin participating in the development of the brain and nervous system and also affecting their function. It reduces cholesterol absorption, lowers homocysteine levels in the body, and thus reduces the risk of atherosclerosis.
Hypersensitivity reactions to egg protein
Egg protein serves as a significant source of allergens that can result in severe food allergies, particularly in children. The two main protein components of eggs, namely ovoalbumin and ovoomukoid, are responsible for the strongest hypersensitivity reactions that persist even after thermal processing. Additionally, livetin, a component of egg yolk, can also lead to cross-allergies with feathers.
The lipid recognized as cholesterol
Cholesterol constitutes 0.3% of the egg weight and is indispensable as a natural component of the egg as a reproductive cell. The liver produces 13 g of cholesterol per day, and one egg contains about 180 mg of this compound. When eggs are consumed, the liver reduces cholesterol production to maintain its proper level. The latest studies show that cholesterol in eggs has little effect on blood cholesterol levels in healthy people who are actively engaged in sports. This is due to the fact that cholesterol absorption is characterized by high levels of individual cholesterol and it varies in the range of 15–85%. Individuals with a genetic predisposition to overproduction of cholesterol should pay special attention to products with high cholesterol content. It is worth noting that the latest reports from the American Heart Association do not specify exactly how many eggs we can eat, but rather specify how much cholesterol should be consumed per day, which is 300 mg. The cholesterol content in eggs can vary, as factors such as the breed of the hens or the method of rearing can influence the values.
