BREAST MILK

From Big Medical Encyclopedia

BREAST MILK (synonym women's milk) — the secret of mammary glands of the woman having specific and biological specificity.

Of m is the best look write for the child of the first year of life; it provides its full development. During the first days lactations (see) it is allocated colostrum (see), a cut to 3 — to the 4th day loses the idiosyncrasies and transitional milk turns in so naz. On 2 — 3rd week (it is rare on the 4th) it gets constant structure and is called mature milk (tab. 1).

Milk contains a large amount of various substances. Women's milk has some specific features depending on character of food of the feeding woman. G.'s structure of m of the same woman changes seasonally (the smallest protein content, redoxon in milk is noted in January — February), and also from that, to or after feeding of the child sample of milk is taken (content of fat in 100 ml of milk before feeding of the child fluctuates from 0,5 to 5,5 mg, and after feeding — from 3,7 to 9,7 mg). However more or less constant composition of mature women's milk throughout a lactation (tab. 2) is on average marked out.

The quantity and ratio of the main ingredients which are a part of women's milk provide optimal conditions for their digestion and absorption in went. - kish. path of the child. Distinction between the female and cow's milk (which is the most often used for feeding of the child in the absence of women's milk) is very essential. Especially these distinctions come to light at cultivation of cow's milk for preparation of milk mixes (tab. 3).

During the feeding by women's milk on a share squirrel 8% of the general caloric content are necessary, during the feeding by cow's milk — 20%. At natural feeding of the child 48% of caloric content fall to the share of fat, and during the feeding by milk mixes — only 29 — 34%. The amount of lactose (lactose) at cultivation of cow's milk considerably decreases, and caloric content at the expense of carbohydrates is provided with sucrose and other polysaccharides (see. Feeding of children ). At breastfeeding between mother and the child balance when the child exhausts so much milk how many for it it is necessary is established fiziol. It is caused by change of composition of milk during feeding [Hall (V. Hall), 1975]. The mechanism regulating appetite (and consequently, and the caloric content of the received food), ripens at the child to the 6th week of life [S. J. Fomon et al.].

Proteins of women's milk belong to ideal, biol which value is equal to 100%. In G. many various protein fractions among which 18 are identical to serum proteins were allocated to m. There is a distinction in the ratio of separate fractions of protein of female and cow's milk (tab. 4).

Proteins of milk differ on dispersion. Contains in proteins of women's milk much more albumine while in cow's milk there is more caseinogen. The relation makes an albumine/caseinogen in women's milk 3:2, and in cow — 1:4. Besides, the molecule of casein of women's milk is less (30 nanometers), than cow's milk (102 nanometers). During the curdling of women's milk thanks to existence of a large amount of low-molecular proteins, lower content of salts of calcium small gentle flakes are formed. It increases a surface for influence of a gastric juice thanks to what proteins of women's milk are easier digested and acquired, than proteins of cow's milk.

An allergy to G. of m — exclusively unusual occurrence. Still there are no indisputable proofs in favor of its existence (antibodies to G. of m at children are never revealed at natural feeding, and also at its intravenous administration in rather large numbers).

At G. of m there are four classes of immunoglobulins — A, G, M and D (see. Immunoglobulins ). Most immunoglobulin A which cosecretes cells of a mammary gland (secretory immunoglobulin A) is important. Thanks to low proteolytic activity of a gastric juice at children of the first months of life and to availability of inhibitor of trypsin in G. of m destruction of immunoglobulins is late in went. - kish. a path of the child that provides resistance of children of this age to an infection, especially went. - kish. to diseases.

The amino-acid composition of proteins of female and whole cow's milk has no essential distinctions (tab. 5). However at cultivation of cow's milk these distinctions become considerable.

In an organism of children of the first 3 months of life owing to absence or low activity of a tsistationin-sintetaza of a liver amino acid cystine cannot be synthesized (at children of this age it is among irreplaceable amino acids), therefore a large amount of serusoderzhashchy amino acids (especially cystine) in G. by m provides more correct development of the child. Protein of cow's milk is presented generally by a caseinogen which is especially rich with aromatic amino acids, a leucine and isoleucine (amino acids with strongly branched chain). Therefore the overload of a diet of the child protein can cause aminoacidemia (see), edges at relative immaturity of the enzymatic systems participating in metabolism of a leucine and isoleucine, and imperfection of function of kidneys can adversely influence development of c. N of page. The amount of residual nitrogen in women's milk develops hl. obr. also makes Ve of the general nitrogen of milk of nitrogen of amino acids and urea. Ammonia contains in a minute quantity.

Quantity fat in female and cow's milk it is almost identical (3,5 — 3,8%), however fat G. of m is acquired much better (assimilation of 95%), than fat of cow's milk (assimilation is lower than 90%). It is explained by different composition of fat and fat to - t, and also their stereochemical structure. The main component of fat of milk are triglycerides in which stearin to - that joins a glitserol in an outside polo of a zheniya, and palmitic — in internal. Children of the first months have lives activity of a lipase of a pancreas low therefore hydrolysis of fat and dissolution saturated fat to - t with a long carbon chain (stearin and palmitic) are especially complicated. At hydrolysis of fats of cow's milk are formed free fat to - you which are easily saponified by calcium and are brought out of intestines. It leads to irrational loss not only of fat, but also calcium at artificial feeding. Of m differs in lower contents palmitic to - you that promotes easier hydrolysis and full absorption with the help pinocytic (see) products of partial hydrolysis of fat — mono glycerides. Thus, the nutrition value of fats of women's milk expressed by coefficient of digestion of triglycerides, above than at cow.

Especially differ female and cow's milk in structure essential (irreplaceable) polyunsaturated fat to - t (tab. 6).

Higher content essential unsaturated fat to - t has saving effect on protein, increases its comprehensibility, and also promotes manifestation fiziol, effects of vitamins (B 1 , C) also increases resistance of an organism to infections.

Contents linoleic to - you, edges cannot be synthesized in an organism, in women's milk is 5 times higher, than in cow. Its share in the general caloric content of G. of m makes 5%, and in cow — only 0,5%. Matters also arachidonic to - that, being a part of nervous tissue. Women's milk contains prostaglandins and their derivatives which are a component of cellular membranes.

The bigger number of the lowest saturated fat to - t in fat of cow's milk in comparison with women's can irritate went. - kish. a path, and myristic and lauric to - you promote increase in cholesterol of blood. Fats of women's milk contain more phosphatides: in colostrum — 6,1%, mature milk — 1,7% [according to Hilditch] which cause early and plentiful biliation that promotes a resorption of fat in upper parts of a small intestine. Average activity of a lipase (tributiraza), optimum of action a cut is at pH 7,0, in women's milk is 20 — 25 times higher, than in cow. It promotes autolytic hydrolysis of fat of women's milk, since a stomach and consequently, to its easier digestion and assimilation.

Are a part of milk carbohydrates, lactose is basic of which, quantity it in G. the m averages 7,0 — 7,5%, and in cow — 4,0 — 4,5%. Increase in sugar in mature G. of m in comparison with colostrum happens preferential at the expense of lactose (K. V. Orekhov). Along with beta lactose G. of m contain also other carbohydrates. Disaccharides at their high caloric content possess a smaller osmomolyarnost, than monosaccharides. It promotes the best absorption of feedstuffs in a small intestine. The monosaccharide which is contained in lactose a galactose within the first weeks of life is used for synthesis of galaktozotserebrozid. At the same time enrichment of milk mixes the sucrose consisting of glucose and fructose at children of the first weeks of life is undesirable since triozofosfat, formed in the course of metabolism of fructose, can strengthen acidosis due to the increased education milk to - you. Beta Lactose G. of m contrary to alpha lactose of cow's milk is more slowly acquired in a small intestine and manages to reach thick. It provides growth bifidobacteria (see) which interfere with reproduction of putrefactive flora (antiputridnost) of intestines. G.'s Bifidogennost-antiputridnost of m is 40 times higher than cow. It along with beta lactose is promoted by other oligosaccharides, and also some polypeptides of proteins of women's milk and connection connected with coenzyme A and pantothenate of calcium.

Of m contains optimum quantity mineral salts, and the ratio of their concentration provides their best utilization. So, e.g., in G. the ratio of Ca/P makes m 2:1 that increases coefficient of assimilation of Ca to 75%. It is important for process of a mineralization of a skeleton of the child who is quickly growing during this period. At the same time the maintenance of Na, To and other mineral salts rather low therefore there is no delay of osmotically active ions in an organism of the child having low excretory function of kidneys.

A ratio between cations and anions and their qualitative structure G. provide m amphoteric reaction that promotes bigger stability of acid-base equilibrium of blood of the children who are on breastfeeding.

Quantity vitamins in breast milk depends on a season of year and vitamin value of food of the nursing mother. However they are not enough for ensuring the correct development of the child. Reserves of the water-soluble vitamins received by the child vnutriutrobno are limited and are quickly spent and eliminirutsya from an organism in the first 2 — 4 weeks of life. Women's milk in comparison with cow is richer with fat-soluble A, D vitamins, E. G. the m contains not only D3 vitamin, but also its metabolites possessing more expressed action on absorption of calcium in a small intestine.

Colostrum, transitional and partially mature G. m contain important biologically active compounds (nonspecific factors of protection in the form of a lysozyme, the substances stimulating complementary properties of blood, virus neutralizing antibodies, a thermostable «anti-staphylococcal» factor, and also hormones and enzymes). Along with autolytic enzymes in G. the m found aminotransferases, a diastase, dehydrogenases, a catalase, etc. Corticosteroid activity of G. of m is nearly 3 times higher than cow. It is important, especially in the first days and weeks of life as many systems there is functionally not enough zrela, and active immunity during this period only begins to form.

The mammary gland is an election threshold for the medicinal substances accepted by mother. However alcohol, nicotine, caffeine, morphine, iodine, acetilsalicylic to - that, and various aromatic substances can pass arsenic, some hypnotic drugs (e.g., veronal) into milk that should be considered in the period of a lactation.

The feeding woman shall decant excesses of milk. The decanted milk is used for feeding of the children deprived for any of several reasons of milk of mother. On collection points for G. of m it is mixed. The received donor milk has srednepostoyanny structure. As a result of transportation, storage, sterilizations etc. change it biol, properties: completely immunoglobulins disappear, vitamin activity sharply decreases, there is a destruction of biologically active agents, a partial denaturation of protein. Pollution of milk is possible.

The decanted milk of each woman delivered to blood donor center shall be exposed to the analysis. Its acidity and a possibility of cultivation is checked by water or milk of animals. For difference of women's milk from milk of animals a large number of the tests based on distinction of their pH is offered. However at pollution of women's milk lactobacilli of its pH decreases (fresh women's milk has acidity 3 — 4 ° according to Turner), and it reacts as counterfeited though cow's milk and was not added.

Test Dahl-Berg is based on distinction physical. properties of proteins of female and cow's milk: add 20% to milk solution of the calcium chloride acidified 0,1 N by HCl solution. After addition of the indicator of methyl orange the test tube is lowered in the boiling bath. Cow's milk instantly turns, and women's does not turn. Reaction with CaCl 2 it can be put also without acidulation.

Test and from 0,01 N by solution a chamois to - you in the presence of Koltgoff's indicator can be carried out (methyl orange + indigo carmine). If to women's milk it was added cow (more than 10%), casein accumulates on a bottom of a test tube and is painted in green color; casein of women's milk remains in suspension.

Reaction E. 3. Umikova: the women's milk mixed with ammonia at the room temperature gradually gets red-violet coloring. Warming up of milk to t ° 60 — 100 ° accelerates emergence of coloring. The cow's milk of coloring mixed with ammonia does not give.


Table 1. Composition of colostrum, transitional and mature women's milk in various terms of a lactation (&vnbsp; %)


Table 2. Composition of women's milk (average figures, according to various authors)


The table 3 Distribution of the General Caloric Content between proteins, fats, carbohydrates in milk and milk mixes (&vnbsp; %)



Table 4. The RATIO of SOME PROTEIN FRACTIONS IN FEMALE AND COW'S MILK (according to G. S. Korobkina, 1970)



Table 5. Amino-acid composition of proteins of female and cow's milk (according to experts a Fao/cart, 1966)



Table 6. Content of fatty acids in fat of female and cow's milk as a percentage to total quantity of fat (according to G. S. Korobkina, 1970)



Bibliography: Vasilyeva L. P. and Gurvich D. B. Quantitative protein content, fat, salts of calcium, magnesium and phosphorus in women's milk in the first week of a lactation, Vopr. okhr. mat. also it is put., t. 12, No. 6, page 65, 1967, bibliogr.; G. S. boxes-on Products of baby food, M., 1970, bibliogr.; Intolerance of milk and program of food, Chronicle of WHO, t. 26, JVe 11, page 525, 1972; Nuts K. V. K of metabolic adaptation of newborn children, Pediatrics, No. I, page 41, 1973; Round A. T. Reference book on a dietetics of children of early age, L., 1971, bibliogr.; Fomon S. J.а.о. Influence of formula concentration on caloric intake and growth of normal infants, Acta paediat. (Uppsala), v. 64, p. 172, 1975; Hall B. Changing composition of human milk and early development of an appetite control, Lancet, v. 1, p. 779, 1975.

A. V. Mazurin.

Яндекс.Метрика