Egg Nutritional Profile: Calories, Proteins, and Vitamins
Analysis of the calories, proteins, lipids, vitamins, and minerals within an egg, the definitive biological superfood.
Introduction: The Anatomy of a Biological “Superfood”
The egg is one of the most complete and nutritionally dense whole foods provided by nature. Within its fragile, hermetically sealed shell lies a sophisticated matrix of nutrients essential for human physiology. It is no coincidence that it is frequently termed a “superfood” or “nature’s multivitamin”: despite a modest caloric intake, it delivers high-biological-value proteins, beneficial lipids, and an extensive spectrum of fundamental vitamins and trace minerals.
But what, precisely, constitutes the interior of an egg? In this article, we shall perform a granular audit of its nutritional identity, deconstructing every element from primary macronutrients to the most precious bioactive micronutrients.
Our analysis utilises precise data derived from the food composition databases of CREA (Council for Agricultural Research and Economics), Italy’s leading authority on nutrition. Our objective is to provide an authoritative, accessible guide to understanding why the egg remains an unrivalled cornerstone of a healthy, performance-oriented diet.
Macronutrient Analysis: High-Biological-Value Proteins and Beneficial Lipids
Macronutrients are the substrates that provide the body with metabolic energy: proteins, lipids, and carbohydrates. The egg is virtually carbohydrate-free, serving instead as an elite source of the other two pillars.
Proteins: The Biological Gold Standard
Egg proteins are considered the “Gold Standard” against which all other food proteins are measured. The rationale? They possess a Biological Value (BV) of 100, the maximum attainable score. This indicates they contain all nine essential amino acids (EAAs) in the exact proportions required for human tissue synthesis and repair—from skeletal muscle to internal organs. A medium egg (approx. 60g) contains roughly 7–8 grams of these premium proteins, distributed almost equitably between the yolk and the albumen.
Lipids: Quality Concentrated in the Yolk
The lipids within an egg (approx. 5–6 grams in a medium egg) are sequestered almost exclusively in the yolk. Contrary to antiquated dietary fears, these fats are predominantly “beneficial.” The fatty acid profile is typically structured as follows:
- Monounsaturated Fats (approx. 40%): Primarily oleic acid, the same heart-healthy lipid found in extra virgin olive oil.
- Polyunsaturated Fats (approx. 20%): Including essential fatty acids such as Omega-6 and Omega-3.
- Saturated Fats (approx. 30%): Present in modest amounts (approx. 1.6 grams), significantly lower than levels found in other protein sources like aged cheeses or red meats.
The Vitelline Treasure: Essential Vitamins and Trace Minerals
It is within the yolk—once the subject of undue clinical scrutiny—that an incredible treasury of micronutrients is concentrated. The egg is one of the few natural dietary sources of several crucial vitamins.
- Vitamin D: Essential for skeletal integrity (facilitating calcium absorption) and the modulation of the immune system. The egg is one of the rare foods to provide this naturally.
- Vitamin B12 (Cobalamin): Vital for neurological health and the formation of red blood cells. It is an indispensable component of vegetarian nutritional strategies.
- Vitamin A (Retinol): Crucial for ocular health, dermal integrity, and immune function.
- Choline: An essential nutrient often grouped with B-vitamins. The egg is one of the primary dietary sources of choline, which is vital for neuro-cognitive health, memory, and hepatic (liver) function.
- Selenium: A potent antioxidant mineral that protects cells from oxidative stress and supports thyroid metabolism. Selenium-enriched eggs are an excellent conduit for this trace element.
- Lutein and Zeaxantina: Two carotenoid antioxidants that accumulate in the retina, acting as a natural filter against harmful blue light and reducing the risk of age-related macular degeneration.
Comprehensive Nutritional Data: Per 100g vs. Standard Medium Egg
For a complete overview, the following table details the average nutritional values per 100 grams of product (approx. two small eggs) and for a single standard medium egg (edible weight approx. 55–60 grams).
| Nutrient | Value per 100g | Value per Medium Egg (~60g) |
|---|---|---|
| Energy | 143 kcal | ~ 80 kcal |
| Water | 75.8 g | ~ 45.5 g |
| Protein | 12.6 g | ~ 7.5 g |
| Total Lipids (Fats) | 9.5 g | ~ 5.7 g |
| ↳ Saturated | 3.1 g | ~ 1.8 g |
| ↳ Monounsaturated | 3.8 g | ~ 2.3 g |
| ↳ Polyunsaturated | 1.4 g | ~ 0.8 g |
| Cholesterol | 372 mg | ~ 223 mg |
| Carbohydrates | 1.1 g | ~ 0.6 g |
| ↳ Sugars | 1.1 g | ~ 0.6 g |
| Phosphorus | 224 mg | ~ 134 mg |
| Calcium | 56 mg | ~ 33 mg |
| Iron | 1.8 mg | ~ 1.1 mg |
| Sodium | 144 mg | ~ 86 mg |
| Selenium | 30.8 µg | ~ 18.5 µg |
| Vitamin A | 227 µg | ~ 136 µg |
| Vitamin D | 1.8 µg | ~ 1.1 µg |
| Vitamin B12 | 2.5 µg | ~ 1.5 µg |
| Folate (B9) | 44 µg | ~ 26 µg |
| Choline | 294 mg | ~ 176 mg |
(Source: Average data synthesised from CREA and USDA composition tables)
Conclusion: An Unrivalled Nutritional Matrix
Upon analysing the empirical data, it is evident why the egg maintains its standing as a premier superfood. At approximately 80 calories, a single egg provides a significant percentage of the daily requirement for numerous vital nutrients: ultra-high-quality proteins, fat-soluble and water-soluble vitamins, essential minerals, and unique bioactive compounds like choline and lutein.
It is an efficient, versatile, and economically accessible whole food. Integrating eggs into a diverse and balanced diet remains one of the most sophisticated choices one can make to nourish the body completely and naturally.