Sugar in breast milk affects newborn immunity

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 of lactation 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.), as well as calorie content. 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 has a significant calorie content, 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 in color, but differs in its larger volume and 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 of 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.

Breastfeeding and bottle feeding: pros and cons

Mother's milk is an almost irreplaceable product for a baby with a unique composition.
It allows the baby to receive all the nutrients necessary for growth and development, and the mother does not have to worry too much about the balance of the child’s diet. However, there are circumstances in which breastfeeding is not possible and a substitute must be sought. And the best option in this case is artificial mixtures. The term "artificial" does not mean something bad. At least, such compositions are able to fully provide the child with the necessary substances, unlike, for example, cow's or goat's milk.

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.

Why is breast milk better than formula, and why is formula better than milk? Compare and draw conclusions

So, breast milk or formula? If possible, it is certainly better to choose the first, and here's why:

• breast milk has an optimal composition that adapts to the baby’s needs;
• on it, children do not gain excess weight, because they eat exactly as much as they need, eating according to hunger and appetite, while force-feeding with formula can lead to overeating;
• the first product that a child receives during breastfeeding is colostrum - and its value for the body is difficult to overestimate;
• milk is always where the mother is, which means you can feed a hungry child anywhere at any time. In addition, there is no need to spend money on the mixtures themselves, as well as various devices - bottles, nipples, sterilizers;
• When a child eats breast milk while being close to his mother, a positive psychological contact arises. Such closeness, alas, cannot be achieved with artificial feeding.

However, you should not think that the need to switch to a mixture for one reason or another is a disaster and tragedy. Moreover, there are advantages here too, for example:

• convenience for a woman: you can eat any food and drink any drink, and spontaneous milk discharge does not cause discomfort;
• freedom: mother can go about her business, leaving the baby in the care of any family member who can prepare a portion of the mixture;
• health and well-being: the mother’s nipples do not crack or hurt, moreover, when lactation gradually passes, the risk of lactostasis and mastitis goes away, and the general hormonal levels return to normal;
• benefits for the baby: on artificial formulas, children are much more willing to gain weight;
• stability: the mother does not have to worry that due to stress, lack of sleep or illness she will have nothing to feed her child - the formula is always at hand, regardless of external circumstances and internal sensations.

Thus, both breastfeeding and artificial feeding have both pros and cons. And, of course, both types of feeding a child have the right to exist. When choosing a feeding format, it is important to be guided not by momentary desires “I want to feed or not,” but by the current situation, and also take into account individual circumstances in the family.

What influences changes in the composition of breast milk

In addition to the stage of lactation, the composition of breast milk is influenced by many other factors: the needs of the child, his age, duration of feeding, etc.

Changing the composition of milk depending on the needs of the child

1. When the mother or child is sick, milk contains antibodies that protect against the disease.
2. The birth of a premature baby increases the period of colostrum release from 3-4 days to two weeks.
3. If a woman is nursing twins and gives each baby a different breast, the composition of the milk in each breast will be different.
4. During a baby's growth spurt, called a growth spurt, milk becomes richer in fat.

Changes in the composition of milk depending on the age of the child

In mature milk, the level of immunoglobulins and antibodies first decreases before the child reaches six months of age, and then begins to increase again. Thanks to this, the immune system of a child up to 6 months has the opportunity to establish the production of its own antibodies against the background of a still fairly high level of maternal antibodies that the child inherited during intrauterine development. Gradually, the baby’s circle of contacts expands, and at the same time, the level of immune factors in milk begins to increase again, which helps protect the baby when encountering pathogens of infectious diseases. From the age of three months, the fat content in milk begins to increase, which compensates for the increased energy needs of the body with a slight increase in milk volume.

Other changes in milk composition

1. 
   During feeding . At the beginning of feeding, the so-called “foremilk” is released, rich in lactose, water-soluble vitamins and protein. Towards the end of feeding, hind milk, rich in fats and fat-soluble vitamins, begins to be released.

2. Within 24 hours. The largest amount of fat is formed 30 minutes after the end of feeding, and if you put the baby to the breast more often, the milk will remain fatty all the time. At the same time, changing the feeding regimen does not in any way affect the level of protein and carbohydrates in milk.
3. Depending on the mother's diet. Changes concern only the level of water-soluble vitamins, polyunsaturated fatty acids, iodine and selenium; the level of other components cannot be corrected. The fluidity and viscosity of milk can be affected by the high concentration of lecithin received by the mother, which in certain cases prevents stagnation of milk.

Thus, the mother and child system functions as a single whole and no formula can come close to breast milk in terms of the richness of its composition. Read more about infant formula in the article.

Compound

Breast milk has an interesting property. Calorie content and its composition changes depending on the needs of the growing baby. Its main components are carbohydrates, proteins and fats. Let's look at them in more detail:

• Squirrels. Breast milk contains 1.03 g of protein per 100 ml. It seems like a little, but this is quite enough for the optimal development of the child. This amount of protein reduces the risk of developing hypertension, obesity and atherosclerosis in subsequent years of life; protective properties appear during puberty. Protein is necessary for the formation of tissues and cells, the synthesis of enzymes, and hormones. It plays a significant role in the development of healthy intestinal microflora and has immunomodulatory properties. In addition, milk contains non-nutritive proteins, for example, lactoferrin, lysozyme, nucleotides, immunoglobulins. They help protect the body from bacteria, viruses and, accordingly, from intestinal, respiratory and other diseases. You should also know that a certain part of the biologically active molecules contained in mother’s breast milk are species-specific. This means that they are only good for your child.
• Fats. Fat content ranges from 4.0–4.3 grams. Breast milk contains a large amount of polyunsaturated fatty acids; they are required for the development of sensory organs, the nervous system, as well as the intellectual development of the baby. In addition, fatty acids enhance protection against infections.
• Carbohydrates. They typically consist of lactose (milk sugar) and oligosaccharides. The carbohydrate content of milk is 6.89 g per 100 ml. Lactose is necessary for the newborn's body. Firstly, it is the basis for galacocerebrosides, which, in turn, are components of the cell walls of body tissues. Secondly, lactose, together with other oligosaccharides, promotes the favorable reproduction of healthy microflora in the intestines, which has a positive effect on digestion processes, the absorption of required vitamins, micro- and macroelements, and also helps in protection against various infections. Mother's milk has a high content of milk sugar, while other types of milk have much lower amounts.
• Vitamins and microelements. Despite the fact that there are large quantities of them in breast milk, they are quickly absorbed by the baby. For example, up to 70% of iron is absorbed, thanks to which children are less likely to suffer from anemia. It also contains potassium, sodium, calcium, magnesium, phosphorus, and zinc.

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 of lactation. 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. 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.

1. Lactoferrin is an 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.
2. Immunoglobulins are 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.
3. Lysozyme - like lactoferrin, has bactericidal activity, disrupting the integrity of the bacterial membrane. In human milk its concentration is 300 times higher than in cow's milk.
4. 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 of building material for the body, have immune activity, and 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 in 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 human milk triglycerides 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 the child’s digestive system synthesizes a sufficient amount of lactase, the enzyme that breaks it down, otherwise significant amounts of undigested lactose lead to symptoms of lactase deficiency. Small amounts of undigested lactose are considered normal and, upon entering the large intestine, are used by beneficial microflora with the release of organic acids that stimulate 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, the biological role of most of them is still poorly understood. 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.

Interesting facts about breast milk

Here are some of them:

Mother's milk is a unique nutritional substrate that helps the baby develop and grow harmoniously. Forms intelligence, develops immunity and sets the level of health for the rest of life.