Nutritional Composition of One Medium-Sized Egg
One medium-sized egg contains approximately 0.72g carbohydrates (0.37g sugars), 9.51g total fat, negligible dietary fiber, and serves as an excellent source of high-quality protein with all essential amino acids 1.
Macronutrient Profile
Based on nutritional data per 100g of eggs, a medium egg (approximately 44-50g) provides:
Protein: Eggs are recognized as having the highest biological value of 100, meaning they provide the most complete protein with optimal essential amino acid composition 2. A medium egg delivers roughly 6-7g of high-quality protein containing all essential amino acids including arginine, histidine, isoleucine, lysine, methionine, phenylalanine, threonine, and valine 3.
Fat: Approximately 9.51g per 100g 1, translating to about 4-5g per medium egg. The fat profile is predominantly unsaturated fatty acids, with oleic acid (a monounsaturated fat) comprising approximately 40% of total fatty acids 4. Eggs contain beneficial omega-3 fatty acids, though amounts vary by production method 5.
Carbohydrates: Minimal at 0.72g per 100g 1, with only 0.37g as sugars—making eggs essentially carbohydrate-free.
Micronutrients and Bioactive Compounds
Eggs are nutrient-dense, providing significant amounts of vitamins and minerals relative to their caloric content 6, 7:
Vitamins: Rich in vitamin B12 (160% RDA per 100g), vitamin A (25% RDA), riboflavin (B2), pantothenic acid (B5), folate, biotin, vitamin D3, and vitamin E 8, 9
Minerals: Excellent source of phosphorus, selenium, iodine, iron, and zinc 8, 9, 4
Carotenoids: Contains lutein and zeaxanthin, important antioxidants for ocular health 10
Cholesterol Content
A medium egg contains approximately 163-165mg of cholesterol 5. However, recent evidence demonstrates that dietary cholesterol from eggs has minimal impact on serum cholesterol levels and shows no significant association with cardiovascular disease risk in general populations 11, 10. The 2015 Dietary Guidelines Advisory Committee concluded that dietary cholesterol is not a "nutrient of concern for overconsumption" 11.
Protein Quality Considerations
Eggs provide 17.4-26.7% of the recommended daily allowance (RDA) of essential amino acids for adults 3. The limiting amino acids in order are phenylalanine + tyrosine, histidine, and lysine, though eggs still maintain superior protein quality compared to most other food sources 3.
Practical Context
One medium egg qualifies as approximately 1 serving from the protein foods group in dietary guidelines 6, 7. Eggs are particularly valuable as an affordable, readily available source of complete protein and essential nutrients, making them especially appropriate for children, adolescents, pregnant and breastfeeding women, the elderly, and undernourished individuals 8.
The nutritional composition can vary slightly based on production methods (cage-free, free-range, organic) and hen diet, particularly affecting omega-3 fatty acid content 5, 9, though these differences are generally modest for standard eggs.