Colostrum

What is Colostrum

Breast secretion, which in women normally begins after childbirth (only exceptionally before), goes through three phases. Consequently, the balance of nutrients in breast milk also changes during these three stages of breastfeeding:

in the first 5 days colostrum is produced
transition milk from 5th-6th to 10th day
from the 10th to the 20th day (onwards) the mature milk.

Colostrum, once misnamed "witch's milk" or "dead milk", for centuries it has been considered harmful to the infant; doctors argued that it should be avoided and suggested alternative practices that lasted at least for the first 7 days.
In reality, colostrum is a fundamental element for early development, as it boasts the unparalleled characteristics of promoting the baby's immune defenses and allowing optimal development of the intestine.

Functions and Nutrients

Newborns have digestive systems that are still immature, with a different ability to digest and absorb dietary nutrients than adults; for this reason, colostrum is quite dense and, compared to mature milk, contains a smaller aqueous fraction to concentrate more the elements in solution and suspension Not surprisingly, colostrum appears as a yellowish (not whitish) and viscous (not liquid) secretion.

Laxative effect

Colostrum has a very slight laxative effect on the child (probable reason for its bad reputation in the past years); this circumstance, apparently negative, is instead very important to favor the very first passage of faeces (called meconium or meconium) inside the "virgin" intestine.

In this way, the colic portion can develop what it will be its definitive intestinal bacterial flora (present on the mother's breast and selected thanks to the immune potential of the food).

It's not all; this mild laxative effect has the function of promoting the excretion of bilirubin from the child's body which, as we shall see, tends to retain it in excess, tending to jaundice. This surplus of bilirubin is due to the death of a large number of red blood cells ( erythrocytes) respectively produced in response to the volume reduction total caused by the separation from the mother at the time of delivery.

Immune Function and Growth Factors

Colostrum contains a large amount of white blood cells (lymphocytes) and immunoglobulins, especially type A, but also IgG and IgM. These defensive proteins are endowed with a remarkable anti-infective capacity and act above all at the level of the intestine; they represent the main components of the so-called "adaptive immune system". It is also hypothesized that IgA, that is the most numerous, can be absorbed at intestinal level and, once in circulation, secreted again in different districts.

Other factors of colostrum belong to the "innate immune system" and are: lactoferrin, lysozyme, lactoperoxidase, complement and proline-rich polypeptides (PRP).

Colostrum also provides a fair number of cytokines (messenger peptides capable of modifying the behavior of certain cells), including: interleukins, tumor necrosis factors, chemokines, etc.

There is no shortage of growth factors, such as insulin-like I (IGF-1) and II (IGF-2), transformation factors alpha, beta 1 and beta 2, fibroblast growth factors, epidemic growth factor, stimulating factors the growth of granulocytes and macrophages, platelet-derived growth factor, vascular endothelial growth factor and colony stimulating factor 1.

In summary, antimicrobials and growth factors represent the main BIOactive component of colostrum; while the former select the intestinal bacterial flora and protect the mucosa from pathogens, the latter promote the development of the intestine itself. Remember also in the mother's milk there are some oligosaccharides able to act as prebiotic agents on the intestinal bacterial flora.

Proteins and Fats

Colostrum is also rich in proteins and, among these, there is no shortage of albumin; these are extremely useful peptides in the transport of numerous substances (such as drugs, hormones, etc.), mineral salts and white blood cells (leukocytes). Among the vitamins, the equivalent retinol (vitamin A) stands out and, with regard to mineral salts, the most present is sodium chloride (it would be interesting to understand if this depends on the nutrition of the nurse or not).

In transition milk, compared to colostrum, the percentage of fat and lactose increases (therefore the caloric intake) and decreases the percentage of proteins and minerals. Over the months, breast milk continues to maintain its nutritional properties, while the quantity tends to decrease physiologically: after 6 months, a woman produces an average of 500cc per day, which is insufficient to cover the nutritional needs of a child of that age. Therefore, you can continue to give milk even after 6 months, as long as it is a supplementary product of food for weaning.
Colostrum therefore has characteristics almost opposite to those of mature milk, because the latter is rich in lactose, lipids and potassium, but is poor in proteins (0.9%, against 2.8% of colostrum).

Curiosity

The importance of colostrum has long been known also in veterinary medicine: in animal husbandry, calves are fed with artificial milk (for the lowest cost), except for the first 7 days, in which colostrum is used because it is rich in defensive substances.