From the Guidelines
Human breast milk is the single most nutritionally complete food available for infants, while eggs are considered the most nutritionally complete single food for adults.
Key Points
- Human breast milk contains the perfect balance of proteins, fats, carbohydrates, vitamins, and minerals needed for infant development, along with immune factors, enzymes, and beneficial bacteria that support a baby's developing immune system 1.
- For adults, eggs are often considered the most nutritionally complete single food, containing high-quality protein with all essential amino acids, healthy fats, vitamins (including B vitamins, A, D, E, and K), and minerals like iron, phosphorus, and selenium 1.
- The nutritional quality of food proteins varies and depends on essential amino acid composition, with foods that contain essential amino acids at levels that facilitate tissue growth and repair being known as complete protein foods, such as eggs, which have the highest biological value of 100 1.
- A varied diet remains essential for optimal nutrition, as even the most nutritionally dense foods have limitations in meeting all human nutritional requirements across different life stages.
Nutritionally Complete Foods
- Breast milk: perfect balance of proteins, fats, carbohydrates, vitamins, and minerals for infant development 1.
- Eggs: high-quality protein with all essential amino acids, healthy fats, vitamins, and minerals for adults 1.
Importance of Varied Diet
- No single food can provide all nutrients humans need throughout life.
- A varied diet is essential to meet all human nutritional requirements across different life stages.
From the Research
Nutritional Completeness of Breast Milk
- Breast milk is considered the universal preferred nutrition for newborn human infants, providing numerous benefits including psychological, convenience, economical, ecological, and nutritional superiority 2.
- However, breast milk has been found to be low in certain nutrients, such as vitamin D, iodine, iron, and vitamin K in developed countries, and additional deficiencies have been documented in resource-poor countries, including vitamin A, vitamin B12, zinc, and vitamin B1/thiamin 2.
- The composition of breast milk may vary depending on environmental factors, including maternal diet, and it is not possible for a lactating woman to transfer nutrients via breast milk that she does not have 2, 3.
Comparison to Other Foods
- Breast milk is essential for infant growth and development, and while alternative forms of infant nutrition, such as infant formulas, may have similar compositions, there is no perfect substitute for breast milk 3.
- Infant formulas are fortified with various amounts of vitamins, minerals, and other nutrients, and are manufactured to be consistent in composition and monitored closely for quality, whereas breast milk composition can vary 2, 3.
Nutrient Content
- Breast milk contains about 87%-88% water, and 124- g/L solid components, including carbohydrates, protein, and fat, as well as various vitamins and minerals, although vitamins D and K may be insufficient 3, 4.
- The nutrients most likely to be limiting in the diets of breastfed infants are minerals, such as iron, zinc, and calcium, which can be obtained from complementary foods, such as iron-fortified cereals, meats, cheese, and yogurt 4.
Functional Compounds
- Breast milk contains functional compounds, such as milk fat globule membrane, proteins, oligosaccharides, growth factors, and microorganisms, which promote infant development and maturation, as well as modulate immunity 5.
- These compounds have potential applications in nutrition and therapy, although their clinical evaluation and commercial exploitation are limited by the difficulty of isolating and producing them on an adequate scale 5.