and why it is important
Human milk is an incredibly important source of nutrition for all infants, and it also has many benefits that extend far beyond the initial growth period of an infant’s life. Human milk contains all the key nutrients needed for a baby’s growth and development—but it is more than just food; it contains a special combination of living cells, enzymes, proteins, hormones, and antibodies that provide the baby with optimal nourishment and protection, as well as neurodevelopmental, immunological, and emotional benefits.
Human milk is produced by the mammary glands in the breasts of female mammals. In the case of humans, lactation, or the process of milk production, is stimulated by the production and secretion of the hormones oxytocin and prolactin, and is regulated by a complex network of signals between the hypothalamus (the area of the human brain that helps control vital body functions such as temperature and hormone secretion) and the pituitary gland.
The composition of human milk is highly variable, not only among individuals but also over time within the same individual, due to biological and environmental factors. As a general rule, though, human milk consists of around 87% water, which is important for hydration and digestion – especially since the digestive system of a newborn baby is still very immature. The other 13% of human milk is made up of proteins, lipids (fats), carbohydrates, minerals and vitamins, as well as other bioactive components.
Proteins are a key component of human milk, and around a third of the proteins contained in milk are whey proteins. Whey proteins are essential for growth and development in infants as they provide essential amino acids that cannot be synthesized in the body; they are also responsible for providing most of the nitrogen in milk which is important for muscle, organ, and bone development.
Lipids are the most energy-rich component of human milk, and are essential for growth, metabolic functioning, and brain development. The main types of fat found in human milk are long-chain polyunsaturated fatty acids (LCPUFAs), which are especially important for brain and vision development, and short-chain fatty acids (SCFAs), which help protect the body from infection.
Carbohydrates account for between 6 and 8% of human milk, serving as another key energy source for infant growth and development. The most prominent carbohydrate in human milk is lactose, which is a type of sugar that helps in the absorption of nutrients; other sources of carbohydrate in human milk include fructose, galactose and oligosaccharides.
Humans milk also contains numerous vitamins and minerals including calcium, phosphorus, magnesium, sodium, potassium, zinc, iron and vitamins A, C and E. The amounts of these vitamins and minerals vary depending on the mother’s diet, but all are essential for building bones, teeth, and muscles, as well as for supporting other vital processes like metabolism and synthesis of hormones.
In addition to its nutritional components, human milk also contains a wide range of specialized components that provide additional advantages, such as immune factors. These immune factors help to protect the baby from infection and other diseases and can also help to nurture the developing gut micro-ecosystem, promoting healthy microbial colonization in the baby’s gut. Human milk also contains hormones that help regulate infant metabolism and support the development of neurological pathways between the brain and other organs.
The benefits of human milk extend far beyond the initial growth period. Studies suggest that breastfeeding continues to reduce the risk of certain diseases and allergies later in life, and that it can even have positive effects on cognitive function and psychological wellbeing.
All in all, the health benefits of human milk are numerous and plentiful. Human milk provides all the key nutrients needed for a baby’s growth, as well as extensive health benefits that extend well beyond the initial period of growth and development. For this reason, it is highly recommended that all babies are fed exclusively with human milk for the first 6 months of life, and ideally longer.