Women's milk is a specific product of the mammary gland and is a complex liquid that contains substances in solution, in emulsion and in colloid dispersion.
Those in solution are represented by:
- sugars: lactose and simple sugars (oligosaccharides). Lactose is the prevailing sugar in quantity;
- mineral salts: sodium, potassium, chlorine, calcium.
- water-soluble vitamins (soluble in water);
- whey protein (whey protein), such as albumin (transport protein of many substances that circulate in the blood) and immunoglobulins (antibodies), which form a yellowish and viscous secretion called "colostrum".
The emulsifying substances in a woman's milk are:
lipids and fat-soluble vitamins (soluble in lipids), which are A, D, K, E.
Those in colloidal dispersion are:
represented by another protein called casein.
In breast milk, whey proteins prevail over the casein.
Oligosaccharides are important because they contribute to the growth of the intestinal bacterial flora, specifically resident in the colon, of the newborn. This flora has particular characteristics: in it are lactobacilli and bifidobacteria (the same as yoghurt), which are anaerobic bacteria (they grow well in airless environments). Precisely to the intestinal flora of the colon, which prevents any putrefaction phenomena from taking place here, the characteristics of the faeces of a breast-fed child are due:
- the sour smell: different from the fetid smell of proteins digested by the intestinal bacterial flora, which characterizes the faeces of the baby fed with artificial milk, which then resemble those of the adult;
- the emission of faeces with a much higher frequency (6-7 shocks per day) compared to the artificially fed baby;
- the golden yellow color of the faeces at the time of issue, which then become greenish because they oxidize in the air.
Bifidobacteria and lactobacilli also provide an anti-inflammatory and anti-infective action because they counteract the growth of gram-negative bacteria and clostridia (other bacteria harmful to the intestine). As a result, breastfed babies have the advantage of rarely falling ill with gastrointestinal phenomena while those who are breastfed often have frequent enteritis. Finally, we have seen that bifidobacteria and lactobacilli have the function of nutrient exchangers : some nutrients that are not digested in the upper portions of the gastrointestinal tract for various reasons, once they reach the colon, are metabolized by these bacteria, which have the properties of transforming them into substances that can be "exchanged" with others, and then absorbed equally.
The secretion of the breast, which begins after the birth (but exceptionally already before), passes through three phases and, consequently, also the distribution of the components of the mother's milk changes during the phases of breastfeeding:
in the first 5 days the colostrum is produced, from the 5th -6th to the 10th day the transitional milk, and from the 10th to the 20th day the mature milk.
Colostrum was once mistakenly called "witch's milk" or even "dead milk", so much so that for centuries doctors have always claimed, always mistakenly, that breast milk should be avoided for the first 7 days because it would not have been nutritious. . In reality, colostrum has been seen to be a fundamental element, because it is a defense milk, rich in immune elements. It is a yellowish, viscous secretion, and contains a large amount of immunoglobulins, especially type A, which have a remarkable ability to protect against infections, particularly intestinal infections. Furthermore, colostrum is rich in albumin, another extremely useful protein for transporting numerous substances (drugs, hormones, etc.), mineral salts, white blood cells, and low in lipids and lactose. Colostrum has characteristics opposite to those of mature milk, because the latter is rich in sugars (lactose) and poor in proteins (0.9%, against 2.8% of colostrum). The importance of colostrum has long been known also in veterinary medicine: in animal breeding, calves are fed with artificial milk (for the lowest cost), except for the first 7 days, when colostrum is used because it is rich in defensive substances.
As the months go by, milk continues to maintain its nutritional properties, although its quantity tends to decrease physiologically; after 6 months a woman produces an average of 500 cc per day, which is an insufficient amount to cover the child's energy needs. Therefore, you can continue to give milk even after 6 months, but no longer as an exclusive element of the diet, so it must be integrated with other foods.
