Breast milk: composition, taste and physiology of lactation. Breast milk. Colostrum and transition milk

Breastfeeding a baby always means a huge and very complex complex of interaction between two organisms - maternal and child. The baby gurgles and smiles - the mother experiences warm feelings of love and tenderness, and the hormone oxytocin released at the same time helps the milk flow. The baby gets sick - an exchange occurs between the saliva and fluid of the attached baby and the receptors on the areola of the mother’s breast, and literally after a few hours the milk will be enriched with immune bodies to the child’s disease. Components breast milk it is impossible to even accurately calculate: researchers estimate their number from 400 to 500, and the composition of milk constantly changes not just depending on the age of the child or time of day, but even during one feeding! It turned out that the milk of mothers who, for some reason, fed the child not from the breast, but from a bottle, was poorer in composition - precisely due to the lack of live interaction between the baby and the breast.

Human breast milk is fundamentally different from cow and goat milk precisely due to the fact that it is intended for feeding not cattle, but infants. Our babies are born weak and immature, and therefore susceptible to external pathogenic factors, therefore various protective substances are very strong in breast milk. The evolutionary task that faces a person is the development of higher nervous activity, therefore, in the first year of life, the baby’s nervous tissue develops most actively, and this is what is facilitated by numerous growth factors and fatty acids in breast milk. Calves and kids are creatures of a different biological species, where it is primarily important to build muscle mass, but their milk is not suitable for human babies!

The task of adapted mixtures is to approximate the composition of cow or goat milk to the human. The amount of proteins is reduced, some vitamins, minerals and fatty acids are added. But add everything to the mix necessary for the child science is unable to achieve substances: 40-50 components is the maximum that allows one to be absorbed without compromising the assimilation of the other. And in breast milk alone there are 130 oligosaccharides, and they all play a role in maintaining health and development child's body! Growth factors, hormones and immune factors are also absent from the mixtures. Therefore, not only breastfeeding, but also expressed milk, not even from own mother, will always be healthier than formula and especially animal milk. But what does this same age difference give? How does the milk of a woman who has just given birth differ from that of a mother nursing a two-year-old?

Colostrum

Colostrum is a rich yellow or even orange color, which begins to be produced in the mammary glands even before birth. Some people leak, some don’t, some women have a little more, others a little less. But even a few drops are already enough to the born baby. The volume of its ventricle is very small, only 5 ml, and therefore large volumes of nutrition are not needed for such a baby and are even harmful.

Colostrum is essentially a very concentrated nutrition. On the first day of a child’s life, the protein content in colostrum is approximately 3 times higher than in mature milk! Colostrum protein is special: it is very finely dispersed, easier to digest, and does not require large quantity digestive juices and does not cause stress at work digestive tract.
but there is very little water in colostrum, because the baby is not yet able to process large volumes of liquid: the kidneys need time to adapt from prenatal period. But the baby is already born with a supply of water, protecting his body from dehydration until the liquid-rich milk arrives.
but the main advantage of colostrum is its enormous saturation with protective factors. For example, the yellow-orange color is given to it by the same substance as carrots - beta-carotene. It is a precursor to vitamin A, which is also a very powerful natural immunostimulant and adaptogen.
There are many different immunoglobulins in colostrum, of which experts attach the main importance to the so-called secretory immunoglobulin A: literally from the first drops it begins to protect the baby’s mucous membranes, which are always the main gateway for infection, and covers protective layer walls gastrointestinal tract baby, protecting him from pathogens. The content of immunoglobulin A in colostrum is so high that in just one day a newborn child receives an amount 50 times more than the therapeutic dose for adults with impaired immunity.
immunoglobulin A remains active in the gastrointestinal tract precisely in the environment that is typical for a breastfed child (it is less active when supplemented with formula).
and this is not the only beneficial substance in colostrum and breast milk that works best when fully breastfed! For example, a complex of breast milk, called HAMLET (an abbreviation for Human Alpha-lactalbumin Made Lethal to Tumor cells - human alpha-lactalbumin that kills tumor cells), is effective even against cancer and is now used in the most modern anticancer drugs. For adults this is a very expensive treatment, but infants simply receive it with colostrum and mother's milk! But this complex begins to work only in the baby’s stomach and only in the environment that develops during breastfeeding.
among other things, colostrum has a mild laxative effect, which cleanses the baby’s intestines of excess bilirubin, preventing the development of pathological jaundice. A baby who attaches to the breast shortly after birth immediately receives protection from possible dangers in an unfamiliar environment. That is why knowledgeable experts emphasize the importance of the child receiving colostrum in the first days and preserving exclusively breastfeeding in the first months of the baby's life!

Transition milk

So, in the first days after the baby is born, the mother feeds him colostrum, which is extremely valuable, but in small quantities. However, after 2-3 days (provided they are together), most babies sharply increase the frequency of feeding, starting to demand the breast literally every half hour. This means that the baby has already matured to receive food more plentiful than colostrum - and thanks to more frequent breastfeeding, the mother begins to produce milk.

The milk that is produced following colostrum until the baby is 2 weeks old is called transitional milk. First it has yellowish color, like colostrum, which gradually turns white. These days, the amount of protein, sodium, potassium, immunoglobulins and vitamins A and E in milk gradually decreases. But the content of fats, carbohydrates and B vitamins increases. And of course, there is much more of it in volume! These days are an important period for both the quantity and quality of milk. Now it is especially important to feed your baby as often as possible! In response to stimulation by the baby's sucking, the glandular tissue of the breast actively develops, in which milk will be produced, not only in the near future, but throughout the entire feeding period. The more glandular cells, the more milk production, therefore frequent feedings in the first 2 weeks of life they provide the baby with a constant “milk supply”!
In the first weeks after birth, the mammary gland is very responsive to baby suckling. For mothers who feed on demand, milk comes not only faster, but also with a richer composition! Studies in Moscow maternity hospitals have shown that mothers who fed on demand, by the time they were discharged from the hospital, produced almost 2 times more milk per day than those who fed by the hour. At the same time, babies who were with their mothers received milk during the day, which turned out to be 1.6 times richer in proteins, 1.8 times richer in fats, and 1.3 times richer in vitamins C. So the secret of “better quality milk” is simple: feed more often!

Breast milk is produced by special cells of the glandular (secretory) tissue of the mammary gland - lactocytes under the influence of the hormones of the female reproductive system progesterone and estrogen during pregnancy. At the same time, glandular tissue mammary gland grows, and from the second half of pregnancy, secretory cells begin to produce colostrum, which three days after birth passes into transitional and then into mature breast milk.

Breast milk is produced by secretory cells located in the glandular tissue of the mammary gland (lactocytes) under the influence of the hormone prolactin, the level of which increases after the start of breastfeeding. It stimulates the production of breast milk necessary for the next feeding of the baby.

Also, a specific inhibitor is determined in breast milk, a biologically active substance that inhibits milk production - FIL (factor inhibiting lactation). The longer breast milk remains in the mammary gland and is not removed from it by sucking or expressing, the stronger the effect of this factor, which leads to inhibition of the production of breast milk by lactocytes. This mechanism protects the mammary gland from overfilling the ducts and traumatizing the glandular tissue, and also allows the baby to independently regulate the intensity of milk production by the mammary glands. As the need for milk increases, the baby suckles more often, more actively and for longer, so milk (and inhibitor) is removed more intensively, and the rate of milk production increases, and the baby receives more milk. This regulatory mechanism is also activated when expressing breast milk, when at a certain point the baby cannot be breastfed:

according to indications from the mother (treatment with various drugs, infectious diseases, complications after childbirth);
indications from the child (weakness and prematurity, central nervous system diseases).

In this case, the inhibitor is also removed from the breast along with the milk, and the rate of milk production increases.

The release of breast milk from the mammary glands occurs under the influence of another hormonal factor - oxytocin, which is reflexively produced by the mother's pituitary gland when the baby is sucked.

Breast milk: types

Colostrum

This type of milk is produced by the mammary glands in small quantities in the second half of pregnancy and after the birth of the child and is considered the earliest milk - it is fed to the baby immediately after birth (often in the delivery room). Distinctive characteristics of colostrum and mature milk are:

more proteins;
less fat, but higher calorie content;
more microelements and fat-soluble vitamins (groups A, E, K), as well as vitamin C and less water-soluble vitamins;
less lactose (milk sugar).

Colostrum is produced in smaller quantities than mature milk, but it ensures that the baby’s digestive system gets used to new operating conditions.
Colostrum also contains high level all protective components - immunoglobulins and active leukocytes, therefore this food product is considered immunostimulating and protective medicine, which is vital for a newborn.

Transition milk

Transitional milk begins to be released after birth from 4-5 days until the end of the second week. It contains more fat than colostrum and gradually, in terms of its basic composition, it begins to approach mature milk.

Mature milk

Mature milk begins to be produced from the end of the 2nd week. But during lactation, its qualitative composition also changes and can be different during the day, and sometimes during one feeding. This depends on many factors (diet and drinking regime nursing mother, her psycho-emotional state). It is also noted that at the beginning of feeding (the first portions) the milk is thinner (it is recommended to express them), towards the end of sucking the milk is thicker and fattier (feeding cannot be interrupted until the baby stops breastfeeding, and it is also recommended to start next feeding from the breast that the baby was previously fed).

Colostrum

Colostrum is the first milk that is produced by the lactocytes of the woman’s mammary gland immediately after the birth of the baby, and sometimes even from the second half of pregnancy (in varying volumes - from a few drops to completely filling the milk ducts). Before the production of mature milk begins, the baby feeds on colostrum, which is a rather thick liquid and can range in color from bluish-transparent to yellow-orange.

This product has high nutritional value and is easily digested in the gastrointestinal tract, therefore it is considered the most suitable nutrition for a newborn. Colostrum prepares the baby's digestive system for more efficient absorption of transitional and mature breast milk. Colostrum contains a lot of proteins, essential amino acids and vitamins, but less fat. With the help of this indispensable food product for a newborn, the intestines are populated with beneficial bacteria. Colostrum has a mild laxative effect, which promotes the release of original feces (meconium) and the removal of bilirubin from the baby’s body, which is formed during the breakdown of fetal hemoglobin, preventing the development of jaundice in newborns.

Immediately after birth, colostrum is produced in very small quantities - sufficient for the baby and unnoticeable for the mother. Moreover, if the baby is actively sucking the breast, the newborn passes meconium and there is urination, colostrum is produced in sufficient quantities. Therefore, it is important from birth to feed the baby on demand:

if a newborn is rarely put to the breast (less than eight times a day), the baby may develop hypoglycemia (a drop in blood sugar levels);
frequent breastfeeding promotes contraction of the uterus after childbirth;
Active sucking by a newborn stimulates the breast, which promotes milk production.

The initial volume of a newborn's stomach does not exceed one teaspoon, while the baby's saturation is ensured by the high nutritional value of colostrum, so the amount that the baby receives when breastfeeding on demand is sufficient for the normal functioning of the digestive system and normal weight gain. In this case, physiological weight loss from 5 to 7% on the second - fourth days of life is considered normal occurrence, so additional feeding with the mixture is not required. Weight loss greater than 8% is:

a signal of the presence of a pathological condition;
improper organization of feeding;
a sign of ineffective sucking.

In these conditions, consultation with a pediatrician is necessary.

Colostrum is gradually replaced by mature breast milk. After three days, transitional milk appears in the breast - it is more liquid compared to colostrum, so the volume of one feeding increases. And by the end of the second week of a baby’s life, transitional milk turns into mature milk. An increase in milk production is noticeable in the condition of the breasts - they become heavier and swell. If the baby, immediately after birth, is given the opportunity to breastfeed on demand (according to WHO breastfeeding principles) - as much as he needs to be full - from 8 to 12 times a day, which stimulates the production of milk by secretory cells.

Breast milk: properties and composition

The composition of mature breast milk fully meets all the needs of the baby in quantitative and qualitative composition, changes as the child grows, and cannot be compared with any of the existing infant formulas, even those that fully match its composition.

The main components of breast milk include:

Fats

These components are considered the most variable ingredients in breast milk - because the fat content in breast milk changes both within one feeding, throughout the day and as the baby grows (in accordance with its energy needs). Breast milk is many times superior to cow's milk and adapted milk formulas in terms of the structure of fats, which are better absorbed. It also contains the enzyme lipase (enzyme) - a substance that helps digest fats, which are almost completely absorbed by the body. It also contains essential fatty acids that are part of the sheaths of nerve fibers, which ensure the passage of nerve impulses.

At the beginning of feeding, mother's milk is significantly poorer in fat - it is like skim or skim milk, but gradually the amount of essential fats increases - their greatest number in the last portion of milk: “cream”. This portion of breast milk contains a “satiety factor” that makes the baby feel full and stop breastfeeding.

It is important to know that a child screams not only when hungry, but also when thirsty or demanding attention and protection (an emotional reaction when wanting to be picked up).

When thirsty, the baby suckles at the breast for several minutes and is quite satisfied with the first portions of low-fat milk, but if the baby is hungry, he will suck at the breast until he is completely full.

Squirrels

These high-quality components are the basis for the growth and proper development of the baby's body. Squirrels playing important role in the first year of a child's life, when he grows faster than in any other period of development. Breast milk, like any other milk, contains two main proteins - casein and whey protein. Whey protein is easily digested in the baby's intestines, while casein is a protein that is involved in milk curdling, but is more difficult to digest. Breast milk contains more whey protein. This makes it significantly different from cow's and goat's milk, which contain more casein, as well as formula milk. Also, breast milk, in addition to whey protein, contains other proteins that are usually absent in goat and cow's milk, as well as in infant formulas, these include:

taurine is a protein that improves brain and peripheral development nervous system;
Lactoferrin is a specific protein that helps with the transport and utilization of iron from breast milk, and also suppresses the activity of pathogenic bacteria and fungi in the intestines.

Breast milk contains lysozymes - special enzymes and natural antibiotics that help destroy pathogenic microorganisms.

Breast milk proteins are easier to digest than cow's and goat's milk proteins, as well as the protein components contained in infant formula. Therefore, breast milk remains in the baby’s stomach for a short period of time, quickly entering the intestines, and the milk formula lingers in the stomach for 2-3 hours. In this regard, it is recommended to feed babies with the formula at certain intervals (according to the regimen), and when natural feeding– without restrictions (on request). It is important to remember that keeping the baby at the breast for a long time and frequent feeding of the baby can lead to overfeeding - regurgitation and intestinal colic. It is important to remember that a baby’s crying is not always a desire to eat - there may be other reasons for the baby’s anxiety (pain, temperature, cold or heat, thirst), as well as a lack of milk due to hypogalactia, mastitis and lactostasis.

Sugars (carbohydrates)

Human milk contains 20-30% more milk sugar (lactose) compared to animal milk. To bring adapted milk formulas closer in taste to breast milk, glucose or sucrose is added to them. At the same time, milk sugar has greater energy value and is important for the development and differentiation of neurons in the brain and central nervous system of the infant. Lactose improves calcium absorption and promotes the growth of positive intestinal microflora.

Iron

Protective substances

Mother's milk contains components that are unique in their structure and properties, capable of destroying infectious agents, and preventing the development and progression of viral, bacterial and fungal infections in the body of a newborn and infant. These include leukocytes - killers and helpers (white blood cells), as well as immunoglobulins (antibodies). Therefore, it is believed that the best protection for a baby is mother’s milk, which can protect the child from all diseases until he develops immunity.

Breast milk: pumping

Today, pumping is not carried out unless necessary - this prevents independent regulation of lactation. The mother produces as much breast milk as the baby needs, and when expressing the remaining milk after each feeding, more mother’s milk arrives, and this leads to lactostasis, and then mastitis.

But situations may arise when pumping is necessary:

when the baby is weak or premature and cannot suck on his own;
if a newborn or infant refuses to suckle;
when the mother is ill, when feeding for a certain time is impossible, but it is important to maintain lactation;
a woman has developed lactostasis or mastitis and needs to “drain” her breasts;
Mom needs to leave home (to work or study) and milk needs to be stored for future use.

Expressing breast milk is done by hand or with a breast pump.

Before the beginning manual expression It is necessary to stimulate the reflex secretion of milk through a light breast massage or a warm shower. When expressing, you need to place your fingers on the border of the areola and nipple from above and below, and then rhythmically press inward and forward, without stopping the rhythmic movements. At first, the milk is released in drops or weak streams, and as the pumping movements continue, the milk begins to flow in several streams until the milk release completely stops - then they begin to express the other breast.

Storing expressed milk

But there are situations when the mother needs to leave, undergo a course of treatment or interrupt maternity leave to go to work, temporarily stop feeding and get an answer to the question - wean the baby from the breast and transfer to artificial feeding or continue feeding with expressed breast milk? The answer depends on the situation with the help of a lactation consultant (pediatrician or family doctor). When feeding with expressed milk, it is necessary to store breast milk properly. But at the same time, you need to remember that depending on the chosen method of storing this product, its composition and shelf life may change.

Store expressed breast milk only in the refrigerator or freezer, and is strictly prohibited room temperature, except when using it in the near future. It can be stored in the refrigerator for no more than two days, and for long-term storage (3 months), breast milk is frozen in the freezer in portions, in sealed (special) tightly sealed containers: bags or containers. Thawing breast milk should be done at room temperature or when placed in a container with warm water However, it is not recommended to use a microwave oven for these purposes. Thawed milk tastes different from fresh milk and has a “stratified” appearance. Re-freezing breast milk is not permitted.

Storing breast milk outside the refrigerator

The shelf life of expressed breast milk at temperatures from 16 to 26˚C should be no more than 3-4 hours, and then all its antibacterial and protective properties gradually decrease (some sources describe the shelf life of this food product at room temperature for up to 6 hours, but at the same time everything is his beneficial features will change significantly). That's why the best way Preserving all the quality indicators of mother's milk will be its proper storage - in the refrigerator or freezer.

Storing breast milk in the refrigerator

When storing expressed breast milk in the refrigerator, use it within a week and it is best to store it in the main compartment of the refrigerator. At the same time, many studies show that there are significantly fewer pathogenic bacteria in chilled breast milk than directly after pumping(!), and this is due to active work macrophages - cells that kill pathogenic microorganisms. When frozen, macrophages die. This storage method is considered the most preferable for expressed breast milk.

Freezing breast milk

Freezing of mother's milk is carried out at a temperature of -13-18˚C, in a regular freezer breast milk can be stored for up to 3 - 4 months, and with deep freezing and a constant storage temperature: -18˚-20˚C, expressed milk can be store for 6 months or longer.

Anna Usynina

neonatologist

Associate Professor of the Department of Neonatology and

perinatology

Northern State

medical university

Astrakhan.

Where does it all begin?

Colostrum is the very first milk, which is a thick, sticky liquid. yellow color. A feature of the colostrum phase of lactation is that the amount of colostrum is very small. This usually worries mothers: how will they be able to feed the baby if droplets are coming out, and sometimes even with difficulty? Some women experience a freer flow of colostrum milk. As a rule, this applies to multiparous patients,

In any case, the average volume of colostrum is 30 ml per day. However, the density of colostrum is quite high. Its energy capacity exceeds that of more mature milk, reaching 150 kcal per 100 ml, while milk with established lactation contains an average of 70 kcal per 100 ml. Thus, by receiving drops of colostrum on the first or second day, the child can fully satisfy his energy needs. That is why it is so important not to limit the baby’s stay at the mother’s breast! And if the baby sleeps for too long in the first days after birth (more than 3 hours), no matter how sorry it would be to disturb his sleep, you should wake the baby up and put him to the breast. Such actions will help, among other things, to avoid large weight loss that is possible in the first days after birth.

Despite the small volume of colostrum received, a healthy child does not need additional fluids, and supplementary feeding adapted mixture is prescribed only according to indications, if changing the feeding regimen fails (more frequent feedings, monitoring correct application to the breast) to achieve more effective breastfeeding.

What did nature provide?

The exceptional value of colostrum is determined by its composition. Colostrum contains a lot of protein, fat-soluble vitamins (such as vitamins A, E), minerals, but little carbohydrates (in particular, the main milk sugar - lactase) and fat. Over time, the ratio of essential nutrients changes (see table), adapting to the needs of the growing baby.

The composition of colostrum corresponds to the ability of a newborn baby to absorb nutrition in the first days of life. So, during this period, the baby’s kidneys are not functionally ready to process a large volume of liquid, but the volume of colostrum received is small. The intestinal production of its own lactase (the enzyme that digests milk sugar - lactose) is insufficient in the first days. But colostrum does not contain as much lactose as mature milk.

It is known that human milk, especially colostrum, contains numerous growth factors - substances that are complex in their composition and act as stimulators for the development of tissues in the human body. Thus, the transmission from mother to baby of nerve tissue growth factor and epidermal growth factor (upper layer of skin) is extremely important. This is of great physiological significance, since, no longer being directly connected with the mother, the still immature organism of the child through mother’s milk receives specific substances that regulate its future life and development.

It has been noted that a child receiving colostrum has a lower risk of developing allergic diseases in the future, so the so-called “early start” of breastfeeding is important.

It is known that many newborns in the first days of life have so-called physiological jaundice, associated with an increase in the level of bilirubin in the baby’s blood. The intake of colostrum milk in sufficient quantities can prevent the development of intense jaundice, since entering the baby’s intestines, colostrum enhances its peristalsis, thus promoting faster bowel emptying and, accordingly, the rapid removal of pigment.

Surprisingly, during the period when lactation begins to fade, the composition of milk becomes close to colostrum. This has great physiological significance. The mother’s body is trying to finally provide the baby with some supply of protective substances that colostrum is so rich in.

Transition milk

Following colostrum, so-called transition milk begins to be produced. The beginning of its production during full-term pregnancy occurs at a period corresponding to approximately 1.5-3 days postpartum period. It is at this time that the composition of milk changes quite dramatically; its lactose content increases. Lactose is a carbohydrate, the milk sugar that gives milk its sweet taste. Due to the increase in the amount of lactose, the volume of milk produced by the glands noticeably increases. The fact is that lactose is osmotically active component milk. In other words, it seems to attract liquid onto itself.

At this time, a nursing woman experiences a feeling of “milk flow” - the mammary glands become larger, a tingling sensation and heat arise in them. For many mothers, the vascular venous network on the chest becomes more noticeable.

During this period, even more milk may be formed in the glands than is required to feed the baby. Then, even after long-term feeding the woman does not feel that the breasts are free, the feeling of fullness of the glands persists. In this case, it is recommended to express milk after feedings or between them (as the glands fill). In order to avoid problems associated with an excess of milk, when lactation begins, there should be no excess fluid intake in order to improve milk production. Sometimes a woman’s desire to feel a faster flow of milk leads to the consumption of large amounts of liquid, which causes severe overflow of the glands and the need to express in order to avoid lactostasis. It is often recommended to limit fluids in the first days after birth to 800 ml per day. This approach has a right to exist if this restriction does not cause the woman significant discomfort. After some time, estimated from several days to several weeks, the woman’s body adapts to the needs of the child. Milk is produced as much as the baby needs, lactation is rare long time remains redundant.

Mature milk

About two weeks after birth, so-called mature milk begins to be produced. Its composition is heterogeneous and changes during one feeding. There is a distinction between early and late milk. Early (or foremilk) milk is released at the beginning of feeding. It contains a lot of protein, lactose and, accordingly, water. Foremilk has a bluish tint, there is a lot of it, and it looks watery. The baby basically gets liquid with this milk and “gets drunk.” If feeding continues for a longer time, milk begins to flow to the baby from more distant parts of the gland - late (or hind) milk containing fat: the baby “gets full.” Rich in fat, the amount of which is 4-5 times higher than that in early milk, late milk flows more slowly, but it is this that provides the baby with important nutrients and energy.

The transition from early milk to late milk is not sudden, it occurs gradually. It is important to allow the baby to suckle for as long as he wants, and not to tear the baby off the breast until he finishes feeding himself (does not “fall off” from the breast). Only in this case will the baby be provided with both a sufficient amount of liquid and the nutrients necessary for its growth.

Average chemical composition human milk (g/l)

"The eighth wonder of the world"

Human milk is so a unique product, that it is impossible to copy it exactly, to reproduce this complex of interconnected and irreplaceable components for the development of the baby. No matter how perfect breast milk substitutes are, they can only come close to its composition.

Each component of human milk is not accidental; it has its own biological purpose. Thus, numerous hormones and growth factors found in mother’s milk contribute to the proper maturation of the child’s body, regulate the development of organs and tissues, including immune system, nervous tissue, gastrointestinal tract.

Surprisingly, a mother gives her baby not only nutrients, but also special means for their better absorption. Thus, as a fat component, the child receives, among other things, polyunsaturated fatty acids necessary for the development of the brain and retina of the eyes. infant. At the same time, human milk contains the enzyme lipase, which helps digest fat, since the baby’s digestive system is not yet mature and is not able to completely absorb fat on its own. Human milk fat is emulsified (in the form of tiny globules) for better absorption.

The main protein in human milk is albumin. This is a finely dispersed protein, which, when curdled, forms small flakes that are optimal for digestion. The digestibility of fine proteins in breast milk, as well as its other components, such as iron, is the best.

The ideal balance of amino acids not only provides the child with energy, but is also important for his proper development. Breast milk contains a high content of essential amino acids - the “building blocks” from which proteins are built. These protein substances are called essential, since they are not formed in the body and therefore must be supplied to the child with food. An essential amino acid that the baby’s body is unable to synthesize due to the lack of a specific enzyme is cysteine. It is essential for normal nervous system function.

Thanks to another component of breast milk - taurine - the baby's brain matures, the work of the heart muscle and liver improves. The baby’s body is also unable to synthesize taurine; it must be supplied with food.

Protective properties of milk

Immediately after birth, the child encounters a huge number of different microorganisms that can disrupt the adaptation process and cause infection of the baby’s skin, intestines, and respiratory tract. It would not be easy for a newborn’s body to cope with them on its own. Mother's milk comes to the rescue.

Milk contains many different components that perform a protective function for the baby’s body. Let's name just a few of them.

The most basic are the anti-infective proteins immunoglobulins A, M, G, the first of which is especially important. Immunoglobulin A is primarily necessary to protect the mucous membranes of the digestive tract. It lines the inside of the newborn's intestines, creating good protection against bacteria and their toxins. This is important because the baby’s production of its own immunoglobulin A is not yet perfect. The content of immunoglobulin A in colostrum is especially high.

In addition to immunoglobulins, mother's milk contains substances that have a protective function: lysozyme, lactoferrin, bifidus factor. The latter promotes the growth of bifidobacteria in the baby's intestines. The predominance of these microorganisms among the intestinal flora is an indicator of the absence of dysbiotic disorders in the child’s body. That is, such a baby has a lower risk of getting sick intestinal infection or have dysfunction of the gastrointestinal tract - unstable stool, colic, etc. The protein lactoferrin competes with pathogenic bacteria in the baby’s intestines, “taking away” from them the iron necessary for some microbes to reproduce successfully.

In addition to the indicated soluble components, cells that also perform a protective function pass to the baby with mother’s milk. The main ones are leukocytes and macrophages, whose function is to absorb and “digest” the infectious agent, as well as to produce specific immune substances that act against pathogens.

For a baby in the first year of life, breastfeeding means not only receiving optimal nutrition in all respects. This is also an opportunity for constant communication with mom, which means affirmation of feelings permanent protection and warmth, development of emotions and socialization of the child.

Speaking about the composition of breast milk, first of all, one should distinguish between its qualitative and quantitative composition. If the qualitative composition is relatively constant and includes mainly water, proteins, fats, carbohydrates, vitamins, macro- and microelements, then the quantitative composition is subject to change. Changes in the quantitative composition of the main components of milk depending on the stage are presented in the table.

Quantitative composition of a woman’s breast milk in g/l

Changes in the composition of milk do not occur abruptly, but gradually, affecting not only the main nutrients (proteins, fats, carbohydrates), but also all biologically active substances (vitamins, hormones, minerals, etc.), and also Let us consider these processes in more detail , tracing changes in composition from colostrum to involutive milk.

Colostrum

It would be more correct to call colostrum not one of the types of milk, but its predecessor. It is secreted from the mother during the third trimester of pregnancy and the first three days after birth in the amount of 5-10 ml per day. This is a thick yellowish sticky liquid that is released not in streams, but in separate drops and is closer in composition to blood than to milk. Colostrum is significantly different, thanks to which the child’s body, even with a very small stomach capacity, receives a sufficient amount of energy.

Components of colostrum characterized by high content

Components of colostrum characterized by reduced content

Transition milk

Three days after birth, blood begins to actively circulate in the mammary glands under the influence of hormones, increasing the production of early transitional milk. It is very similar to colostrum, but differs in larger volume and a changed quantitative composition of components. The content of protein, sodium salts, potassium, vitamins A, E decreases and the content of fat, carbohydrates, and B vitamins increases. After 7-8 days, the composition of milk continues to change, but at a lower rate than before, its stabilization begins to occur. This type transitional milk is called late transitional milk. As for the volume of milk during this period, it begins to adapt to the amount that the child sucks, that is, the hormonal regulation of volume is replaced by the so-called autocrine.

Mature milk

2-3 weeks after birth, mature milk begins to be produced, which is characterized by the most stable composition. The concept of stability here is very arbitrary, since very slowly the protein content continues to decrease and the carbohydrate content continues to increase. Changes in the content of the remaining components are not of such a constant nature and are determined by the child’s needs for them, his age and other factors.

Involutive milk

Produced in the mammary gland during lactation. This stage occurs when the child is 2.5-4.2 years old, when the child is put to the breast only 1-2 times a day. The composition of milk at this time becomes more and more similar to colostrum. It contains especially a lot of macrophages, leukocytes, immunoglobulins, phagocytes and other anti-infective factors.

What influences changes in the composition of breast milk

Characteristics and properties of breast milk components

Today, about 500 components of breast milk are known, and the properties and role of each of them are not yet fully understood. All of them can be divided into several groups, differing in structure, properties and functions performed in the body.

Squirrels

Whey proteins and casein. Most of the protein in breast milk is represented by whey proteins, a smaller part is made up of casein fractions. The ratio of whey proteins to casein depends on the stage. In mature milk it is 60:40. The term “casein” is not entirely accurate in this case, since this protein is formed under the action of gastric juice from caseinogen, which, in fact, is found in breast milk. Breast milk proteins can be quickly absorbed by the baby's body. This is achieved through:

small size of casein molecules (compared to cow's milk casein);
the presence of proteolytic enzymes;
the identity of 18 breast milk proteins to blood serum proteins, due to which they can be easily absorbed in the intestines and enter the blood unchanged.

The vast majority of protein supplied from food is a source of amino acids. In the absence or deficiency of certain amino acids (essential), the body will not be able to synthesize its own protein. TO essential amino acids in newborns include phenylalanine, lysine, isoleucine, valine, leucine, methionine, threonine, tryptophan, histidine.

Free amino acids. In addition to protein, milk contains free amino acids. It is believed that the presence of free amino acids in milk, for example, taurine, is explained by the high need for them in a newborn baby, which are not covered only by protein.

Important! Free amino acids in milk complement protein, which serves as a building material for the body.

Breast milk contains a special fraction of proteins that is practically not destroyed in the baby’s digestive system and has immune activity, being components of the body’s defense system.

Lactoferrin– iron-containing glycoprotein. Due to its ability to bind iron, it can block this element in the bacterial cells of pathogenic microorganisms, thereby suppressing their growth.
Immunoglobulins is a group of whey proteins. Their variety is immunoglobulin IgA, which is capable of enveloping the mucous membrane of the intestines and throat, thereby preventing the penetration of viruses and bacteria through it.
Lysozyme– like lactoferrin, it has bactericidal activity, disrupting the integrity of the bacterial membrane. In human milk its concentration is 300 times higher than in cow's milk.
Alpha-lactalbumin— promotes the formation of peptides with immunoregulatory and antibacterial properties, supports the growth of bifid flora in the child’s intestines. When it is broken down in the gastrointestinal tract, bioactive lipids are formed, the so-called HAMLET complex, which helps destroy cancer cells.

Important! Proteins are a source building material for the body, have immune activity, regulate the course of biochemical reactions.

Enzymes and hormones. The main function of enzymes is to accelerate biochemical reactions, and hormones to regulate their speed. Enzymes in breast milk facilitate the absorption of its components, since the synthesis of the child’s own enzymes by the body is still insufficient. Thus, the enzymes pepsinogen and trypsin are directly involved in the breakdown of protein, lipase facilitates the breakdown of fat due to its partial hydrolysis before entering the stomach.

Nucleotides. When they talk about the protein content of milk, they often mean total protein, determined by the calculation method based on nitrogen content. However, the nitrogen-containing compounds of milk include not only proteins, peptides and amino acids, but also other nitrogen-containing compounds. These substances include nucleotides - nitrogen-containing compounds, precursors of DNA and RNA, the content of which in breast milk is 7-10 mg/100 ml. In the human body, their synthesis is limited and occurs only in certain tissues, so food is almost the only opportunity for entry into the body. Their functions are as follows:

maturation of the immune system and formation of an immune response;
a universal source of energy that promotes cell growth and division;
participate in the formation of normal intestinal microflora and the metabolism of essential fatty acids.

Fats

Human milk fat, like most natural fats, has several main components:

triglycerides;
phospholipids;
sterols.

Triglycerides. They are the main part of fat and are esters of glycerol and fatty acids. The structure of triglycerides in human milk differs from triglycerides of other fats in the position of palmitic acid, which ensures its complete absorption by the child’s body, and in the predominance of polyunsaturated fatty acids over saturated fatty acids. Polyunsaturated fatty acids are not synthesized by the human body and are essential. A special place among them is occupied by linoleic acid (the precursor of arachidonic acid) and α-linoleic acid (the precursor of docosahexaenoic and eicosapentaenoic acid), which perform a number of important functions:

promote normal growth;
participate in the formation of the immune response;
necessary for the normal formation of the brain and neuroretina;
are involved in mechanisms that activate digestion and promote the maturation of intestinal cells.

Sterols. Their most important representative in breast milk is cholesterol, which is involved in the formation of cell membranes, nervous tissue, and the synthesis of certain vitamins, in particular vitamin D, hormones and other biologically important substances.

Phospholipids. Their most important representative is lecithin, which limits the deposition of ballast fat and promotes protein synthesis in the body.

Carbohydrates

Human milk carbohydrates contain lactose and oligosaccharides. Fructose, sucrose (less commonly maltose) are not always found.

Lactose. It is the main carbohydrate in human milk. This carbohydrate is found only in milk and is therefore also called milk sugar. Along with providing the body with energy, it performs a number of other important functions. So, when lactose breaks down in the small intestine, galactose is formed, which:

participates in the development of the central nervous system;
promotes the formation of beneficial intestinal microflora.

For the breakdown and further absorption of lactose, it is important that digestive system the child has synthesized a sufficient amount of lactase - the enzyme that breaks it down, otherwise significant amounts of undigested lactose lead to the manifestation of symptoms. Small amounts of undigested lactose are considered normal and, entering the large intestine, are used by beneficial microflora with the release organic acids, stimulating the maturation of intestinal cells and its peristalsis.

Lactose in human milk differs from lactose in cow's milk in its isomeric structure. While in human milk it is β-lactose, in cow's milk it is predominantly α-lactose. β-lactose differs from its isomer in bifidogenic properties and promotes the absorption of Ca, Mg, Mn, Zn. Due to the predominant content of lactose in breast milk, it has a low osmolarity, which is important for the normal absorption of nutrients.

Oligosaccharides. About 130 types of oligosaccharides have been identified, biological role Most of them have not yet been studied enough. Many of them are able to suppress the binding of toxins of viral and microbial origin to intestinal epithelial cells. All oligosaccharides are prebiotics, stimulating the growth of beneficial intestinal microflora.

Vitamins, minerals and trace elements

The content of minerals in human milk is significantly lower than in the milk of most mammals, but it provides all the necessary needs of the child’s body. The content of vitamins depends on the diet of the nursing mother. This is especially true for water-soluble vitamins, such as vitamin C. Vitamin D, although found in breast milk, is not able to fully satisfy the physiological need, so it is added to the baby’s diet additionally.

In contact with

The problem of a lack of breast milk is familiar to many mothers during the breastfeeding period. Some people have little breast milk from the very beginning of feeding their baby. For some, its amount decreases periodically during periods lactation crises. And for some, it almost disappears at some point due to stress or irregularities. It happens that the problem is completely imaginary, and the mother just thinks

While feeding a baby, you can often hear mothers complaining about blue milk that is thin like water. Mothers worry whether the baby is getting enough to eat, whether he has enough calories and microelements. So why is breast milk runny? How to make it fatter and is it necessary to do it? We will answer these questions in this article.

When a newborn is born, the wish for “sweet milk” is very often heard. Yes, in normal conditions human milk is sweet. But its taste may change. In this article we will look at the situation when milk becomes salty - this can happen due to various reasons, starting from the mother’s nutrition, ending with lactostasis or mastitis. Why is human breast milk sweet?

Staphylococcus is often found in breast milk. Mothers usually panic during such tests. What to do if you find staphylococcus? Do I need to get treatment myself? Will a baby get infected if breastfed? Without the correct information, mom can make mistakes. For example, stop breastfeeding when it is absolutely unnecessary. Or, conversely, not paying attention to serious symptoms

As soon as the baby is born, he shows with all his appearance that he wants to eat, opening his mouth slightly and trying to find the nipple. Already at this moment, the nursing mother is thinking about how much milk she has. What does it contain? Are all the necessary microelements for the baby? Mom wants to know if it can affect the composition of breast milk.

How is milk produced in female breast? How long must pass after the previous feeding of the baby for milk to appear in the woman’s body again? What does its quantity depend on? Why does a baby ask for breastfeeding so often at the beginning of life? In this article you will find answers to all these

Many doctors argue that from birth it is necessary to establish a certain feeding regime for the child, explaining their opinion by the fact that breast milk is digested no earlier than after 3 hours. To dispel this myth, an experiment was conducted in which it was determined how much adapted milk formula is digested and at what speed breast milk is absorbed. The study involved 20

Breast milk is produced in the alveoli mammary glands from the blood and lymph of a woman. What mommy eats and drinks is broken down into molecules in the gastrointestinal tract and absorbed into the blood. From the capillaries of the breast tissue, molecules enter the milk through the cells lining the alveoli. Since food is not digested instantly, and molecules are not removed from the blood immediately, this process takes some time.