2 Accreditation and Educational Credit The University of South Carolina School of Medicine-Palmetto Health Continuing Medical Education Organization designates this enduring material for a maximum of 1 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.This CME Activity is planned and presented in accordance with all ACCME Essential Areas and Elements (including the Standards for Commercial Support) and Accreditation Policies.Relevant financial relationships and acknowledgements of commercial support will be disclosed to participants. Faculties are required to disclose off-label/investigative uses of commercial products/devices.
3 Breastfeeding Education for Physicians: The Road to Baby Friendly Designation To be designated as a “Baby Friendly” institution, hospitals must follow the guidelines in the 10 steps and then be evaluated on how well these items are implemented. Part of that designation is staff training. Physicians must receive 3 hours of breastfeeding education for compliance.Jennifer Amrol, MDAssistant Professor of Clinical PediatricsUniversity of South Carolina School of Medicine
4 Objectives Review the anatomy and physiology of breastfeeding. Examine the composition of human milk and the significance of individual components.
5 Breast AnatomyBreast includes mammary tissue, nipple and areola, supporting connective tissue and fat, blood and lymphatic vessels, and nerves.Mature mammary gland has 6 to 10 lobes each of which has a single opening/galactophore in the nipple.
6 Breast Mammary tissue Nipple and Areola AlveoliDuctsNipple and AreolaSupporting connective tissue and fat, blood and lymphatic vessels, nervesAdipose tissue distribution greatly differs among women and is not related to milk productionBreast includes mammary tissue, nipple and areola, supporting connective tissue and fat, blood and lymphatic vessels, and nerves.Mature mammary gland has 6 to 10 lobes each of which has a single opening/galactophore in the nipple.The 3rd, 4th, 5th, and 6th intercostal nerves are essential to the breast’s milk production.
7 Breast Anatomy Mammary tissue Alveoli Ducts Small sacs of milk secreting and storing cells clustered into lobulesSurrounded by myoepithelial cells which contract in response to oxytocin for milk ejectionDuctsConnect lobules to form distinct mammary lobeThen connect lobes to end at the galactophoreDucts beneath areola become fuller due to oxytocin during a feedNumber is not related to milk productionDistinct mammary lobes- important for knowing anatomy and site of infectionLactiferous sinus may not exist based on recent research where US showed easily compressed ducts that seemed to simply transport and not store milk.
8 Breast AnatomyNippleHas an average of 9 milk ducts passing to outsideHas smooth muscle fibers and sensory nervesShape and size vary between womenMontgomery glands are usually not visible before pregnancy and lactation.
9 Inverted NipplesWomen with inverted nipples can breastfed but they many need more help postpartum.She should request assistance with breastfeeding as soon as possible after her baby is born.After delivery, a breast pump might be useful to help evert the nipples. If a pump is not available, a 20ml syringe with the adaptor end cut off and the plunger inserted backwards is used to help draw out a nipple.Avoid bottle and pacifier use so the baby does not become accustomed to the longer artificial nipple which feels and flows differently.When all else fails, an ultra-think silicone nipple shield can be tried temporarily.Nipple preparation during pregnancy is not recommended.
10 Breast Anatomy Areola Circular and pigmented Contains Montgomery glandsSecrete a bacteriostatic, oily fluid to protect the areola and nipple during lactationProduces the mother’s scent that attracts the babyShape and size vary between womenMontgomery glands are usually not visible before pregnancy and lactation.
11 Stages of Lactation Mammogenesis Lactogenesis Galactopoiesis Growth of the breastsIn utero, prepubertal, pubertalLactogenesisFunctional change of the breasts so that they can secrete milkOccurs during pregnancy and initial postpartum periodGalactopoiesisMaintaining the production of milkBegins 9 days postpartumInvolutionTermination of milk productionWith weaning
12 Mammogenesis In utero After birth/before puberty Mammary bulb is seen at weeks gestationFat pad precursor developsRudimentary ductal system is present at birthAfter birth/before pubertySmall set of branching ducts grows with childRemains inactiveLimited milk secretion may be seen at birth due to maternal hormones influence
13 Mammogenesis Puberty -Thelarche Takes 3 to 3 ½ years Occurs 2 ½ to 3 years prior to menarcheInitial stagesIncrease in size and pigmentation of areolaDevelopment of breast budThelarche indicates the beginning of puberty; generally begins at 9.6 years but may be as early as 8yBreast bud is a mass of tissue beneath areola
14 Mammogenesis Puberty -Thelarche Estrogen Progesterone Breast tissue enlargesStimulates growth of mammary ducts into preexisting fat padProgesteroneEffect begins with onset of menses and ovulationSecreted by ovary during luteal phase (second half of menstrual cycle)Stimulates lobulo-alveolar developmentAlveolar clusters grow with each luteal phase and regress with onset of menses and loss of hormonesAnother pituitary factor works along with estrogen- likely growth hormone.Estrogen and progesterone facilitate the formation of the terminal duct lobular unit. Full alveolar development requires pregnancy hormones.Luteal phase is the second half of the menstrual cycle.
15 Lactogenesis Mammary gland develops capacity to secrete milk Includes all steps needed to transform undifferentiated breast tissue in early pregnancy to fully differentiated state after pregnancyTwo stagesBeginning at the twelfth week of pregnancyBeginning shortly after delivery
16 Lactogenesis Stage 1 Occurs by mid pregnancy Pregnancy hormones ProgesteroneLactogenic hormonesProlactin and Human placental hormoneStimulate nipple and areolar growthBreast changesDouble in weightIncreased blood flowGrowth in lobules and alveoli (progesterone effect)Increased secretory activityMammary gland becomes competent to secrete milkAlveoli accumulate colostrumColostrum is secreted immediately postpartum when the newborn feedsMilk secretion is prevented by elevated levels of estrogen and progesteroneEither prolactin or hpl work with progesterone to bring about the final stages of mammary growth and differentiation including nipple and areolar growthWomen may notice superficial veins as breasts enlarge, darkening of areola pigmentation, protrusion of montgomery tubercles. Some women may have a slight leakage of colostrum during the second half of pregnancy.By mid pregnancy, the breast has extensive lobular clusters and lactose can be detected in blood and urine.The secreted glandular fluid contains increased lactose, protein, immunoglobulins and decreased Na and Cl.Elevated levels of progesterone and estrogen keep milk from being secreted until lactogenesis stage 2 when those hormone levels fall. Prolactin level remains elevated.
17 Lactogenesis Stage 2 Occurs whether or not the newborn breastfeeds Day 2 or 3 to day 8 after birthAverage of 40 hours postpartumEarlier in multiparous womenTight junction in alveolar cell closesOnset of copious milk secretionDrop in levels of estrogen and progesteroneRelative increase in prolactin levelsBreasts are full and warmSwitch from endocrine to autocrine controlContinued milk production depends on regular milk removalMajor volume increase occurs around 40h post partum- but anywhere from day 2 to 5; occurs earlier in multiparous women than in primiparous women.Don’t use term “milk comes in” because it leads women to believe there is none before then. Generally there is enough colostrum to meet the term infant’s needs.Autocrine is supply-demand control- continued milk production depends on regular milk removal.
18 Lactogenesis Stage 2 Blood flow, oxygen, and glucose uptake increase ProgesteroneRemoval of placenta with its progesterone is required for milk secretionProgesterone receptors appear to be lost in lactating tissues so that the inhibitory effect of circulating progesterone is decreased once lactation is establishedSo progesterone only birth control can be used once lactation is going wellInsulin, GH, cortisol, and PTHMaternal secretion allows for mobilization of nutrients and minerals required for lactationDecreased progesterone receptors should allow progesterone only birth control to be used once lactation is established.Citrate concentration increases- Increased milk citrate is a reliable marker for stage 2
19 Galactopoesis Begins 9 days after birth and continues until weaning Established milk secretion/production is maintainedContinued autocrine system of controlProlactinRequired to maintain milk secretionOxytocinRequired to produce let-down to allow milk extraction
20 Involution Begins at weaning Regular milk extraction ceasesProlactin is withdrawnIs completed ~40 days after last breastfeedingMilk secretion decreases due to the buildup of inhibitory peptidesMammary gland returns nearly to pre-pregnancy stateProlactin is withdrawn (in many species)
21 Lactation The cyclical process of milk synthesis and secretion Occurs with the help of prolactin and oxytocinRegulation of milk synthesisQuite efficientAverage of ~800 ml/day but volume secreted may vary depending on infant’s requirementMilk productionImproves with relaxationDecreases with maternal stress and fatigueIncreased dopamine and/or norepinephrine inhibit prolactin synthesisStress and fatigue inhibit oxytocin releaseEffect of AlcoholLower levels may enhance milk letdown due to decreased stress but higher doses inhibit oxytocin release thereby inhibiting letdownOpiates also suppress oxytocin releaseTechnically when we use the term lactation, we generally are referring to the stage of galactopoesis
22 Physiology of Lactation Suckling stimulates the release of prolactin from the ant pit and oxytocin from the post pit.
23 Physiology of Lactation ProlactinPolypeptide hormone synthesized in the anterior pituitaryPositive regulation of secretionReleased from anterior pituitary with the peak determined by the intensity of suckling by the infantNegative regulation of secretionMain control is from hypothalamic inhibitory factors (dopamine acts through the D2 receptors in lactotrophs)Stimulates mammary gland ductal growth and epithelial cell proliferationStimulates milk synthesis in mammary gland epithelial cellsSuppresses ovulationStimulates synthesis of mRNA of milk proteinsImportant in suppressing ovulation
24 Physiology of Lactation ProlactinLevels increase from 10 ng/ml in prepregnant state to ~200 ng/ml at termSecretion occurs 7 to 20 times per day with peaks of up to 75 minutesPeak is superimposed on continuous background level of secretionLevels quickly rise with suckling and peak ~30 minutes after start of a feedEffect on milk production is most pronounced in first few weeks after birthLevels are not proportional to milk secretion and do not directly regulate milk synthesis or secretionMore is produced at night so nocturnal feeds are helpful in keeping up supplyMakes mother feels relaxed and sleepyLevels return to low level in 2-3 weeks in nonlactating women
25 Physiology of Lactation Suckling stimulates the release of prolactin from the ant pit and oxytocin from the post pit.
26 Physiology of Lactation OxytocinSynthesized in hypothalamus and stored in the posterior pituitaryRelease is stimulated by sucklingNeuroendocrine reflex has a significant psychological componentOxytocin release may be stimulated by thought, sight, or sound of infantStimulates myoepithelial cells in alveoli to contract and expel milkForcible milk removal is called milk ejection or let-downVariation in perception of let-downAids in uterine involution after deliveryUterine contractions may be associated with “after pains” that indicate oxytocin release
27 Physiology of Lactation Signs of Oxytocin ReleaseTingling sensation in breast before or during a feedMilk flowing when mother thinks of baby or hears crying babyMilk flowing from other breast during feedingMilk streaming from breast if latch is interruptedSlow deep sucks and swallows by the baby during feedUterine pain during feedThirst during a feedLet down may occur several times during a feed- an avg of 2.5x (range of 2-9)
28 Physiology of Lactation Milk productionPositive local regulation by demandIncreased sucklingIncreased emptyingIncreased milk secretion/productionSkin to Skin (SSC) supports successful breastfeedingPartial milk removal sets a new, lower rate of milk productionNegative local regulation of milk productionFeedback Inhibitor of LactationAccumulates in milk between feeds so without removal of milk, secretion/production is inhibitedExplains why an empty breast makes milk faster than a fuller oneDistention or stretch of the alveoliLocal effect to inhibit milk secretion/productionOnce milk removal stops, involution beginsBreastfeeding is influenced positively by early and frequent milk removal and negatively by late, infrequent feeds along with feeding other things before 6 months of age.Is called the “law of demand and supply”Each breast responds to the infant’s needs, moms may exclusively breastfeed more than one infant or use only one breast. Local control allows for feeding from only one breast.An empty breast makes milk faster than a fuller one.
29 Physiology of Lactation Feedback Inhibitor of LactationInhibitory whey protein present in breast milkBuilds up as milk accumulates in the mammary glandWithout milk removal, the inhibitor stops epithelial cells from secreting/producing more milkProtects breast from harmful effects of overfillingOnce milk is removed, secretion restartsAllows production of milk to be determined by infant’s needsEspecially important regulatory mechanism once lactation is established since prolactin does not control milk volume produced
30 Maternal Diet and Milk Supply Mothers make nourishing milk for their infants from all kinds of food. There are no foods that must be avoided, unless mother or baby develops an allergic reaction.Breastfeeding mothers have an increased thirst that usually maintains an adequate fluid intake; no data support the assumption that increasing fluid intake will increase milk volume.Mothers do not need to drink milk to make milk; thirst can be satisfied from a variety of nourishing beverages, including water.Calcium is available not only in milk and milk products but in many other foods, such as broccoli, spinach, kale, bok choy, collards, mustard and turnip greens, almonds, and canned fish.Poor maternal nutrition is not a contraindication to breastfeeding.Mothers following a vegan diet should take a B12 supplement
31 Galactagogues Metoclopramide — most commonly used Domperidone — not approved in USA. Similar to metoclopramide but less side effects as little crosses blood brain barrierFenugreek and other herbal medicines — no scientific data except anecdotal reportsGoat’s rue, milk thistle, anise, basil, blessed thistle, fennel seeds and marshmallow
32 Metoclopramide Effect is to increase prolactin level Benefit shown in small placebo controlled crossover study with increase of 50 cc per feed with dose of at least 30 mg per daySide effectsgastrointestinal, anxiety, sedation, and rare dystonic reactionsNo documented neonatal reactionsShort term: 1–3 weeks is common.No evidence supporting long-term use.Usually wean after 10–14 daysCommon dosing regimen10 mg po qd first dayThen 10 mg po bidThen 10 mg po TIDPatients or lactation consultants may request that physicians prescribe domperidone from compounding pharmacies. FDA issued a caution due to small number of deaths with intravenous formulation and concerns regarding drug importation (American Academy of Breastfeeding Protocol #9). Small RCT (daSilva 2001) of 16 patients showed increase of 49.5 cc with domperidone) compared to 8.0 cc with placebo (p<0.05)
33 Fenugreek Most commonly recommended herbal galactogogue Usual dose is 1-4 capsules ( mg) tid to qidNo standard dosingMay also be taken as one cup of strained tea tid¼ tsp seeds steeped in 8oz water for 10 minutesIncreases supply within 24 to 72 hoursSide effects in motherMaple like odor to sweat, milk, and urineDiarrheaIncreased asthmatic symptomsLower blood sugarContraindicated during pregnancy due to uterine stimulant effectsFenugreek (Trigonella foenum-graecum)treasured as a spice and medicine throughout India and the Middle East for thousands of years. It is a member of the pea family listed as GRAS (generally regarded as safe) by the U.S. Food and Drug Administration. The higher of these doses may be required in relactating or adoptive mothers. Huggins34 reported the anecdotal use of fenugreek in at least 1200 women with increased milk supply within 24 to 72 hours. Reported side effects are rare: maple like odor to sweat, milk, and urine; diarrhea; and increased asthmatic symptoms. Fenugreek is known to lower blood glucose, so caution is advised. Two recent preliminary reports suggest effectiveness.35,36
34 Human Milk Composition Changes are visible over time with thick yellow colostrum at start
35 Human Milk Composition ColostrumDenser milk provided for the first 2-3 days after birthFacilitates the passage of meconium to decrease enterohepatic circulation and thus encourage elimination of bilirubinAids in establishment of Lactobacillus bifidus flora in infant’s gutMilk VolumesDay ml (range of 7-123ml)Day mlDay mlLow volumes encourage frequent feeds to stimulate milk synthesisColostrum Energy Value67 kcal/100mlColostrum componentsHigher concentrations of Na, K, and Cl than mature milkHigher percentage of protein, minerals and fat soluble vitamins than mature milkNewborn’s stomach volume is ~20ml or 5ml/kgVolume varies with parity and # of feedingsColostrum stimulates intestinal peristalsis which decreases enterohepatic circulation, encouraging elimination of bilirubin Low volume of colostrum encourages frequent feedings, which encourages milk to “come in”
36 Human Milk Composition ColostrumDenser milk with higher concentration of proteinsWhite cells and antibodies (especially sIgA)Important immune protection from exposures to environmental micro-organisms40-60% of cells are macrophagesEpidermal growth factorPrepares gut lining to receive nutrients in milkLactosePrevents hypoglycemia and facilitates meconium passage and therefore bilirubin excretionVitamin AProtects the eyes and epithelial surfacesBeta carotene, its precursor, provides yellowish color of colostrumDenser milk with relatively higher concentrations of proteins and antibodies.Protein is largely immunoglobulins (esp sIgA)wbcs are mainly macrophages with the rest lymphs or polymorphonucleocytes.Neutrophils in colostrum promote bacterial killing, phagocytosis, and chemotaxis
37 Human Milk Composition Immunoglobulins in Human Milk(levels decrease over time)Output - mg/24 hoursDay Postpartum IgG IgM IgA,000,000,0008 – ,000Powerful passive immunization against bacterial and viral infections; levels decrease with time, but immunologic protection continues
38 Human Milk Composition All increase except proteinNote the increases in calories, lactose, and fat while the protein decreases from colostrum to mature milk.
39 Human Milk Composition Transitional MilkMilk produced from days 5-12Intermediate composition between colostrum and mature milkVolume continues to increaseMacrophage as percentage of WBCs increases to 80-90%Concentration is 104 to 105 per ml of milk
40 Human Milk Composition Mature MilkMilk produced after ~14 daysContains all the nutrients an infant needs for the first 6 months of life and is uniquely specific for humansFat (3.8%), protein (0.9%), carbohydrates (7.2%), vitamins, minerals, and water (87%)Is easily digested and efficiently usedComposition varies through lactation: over a day, within a feed, and between womenCalories20 calories per ounce (65-75 kcal/100ml)
41 Formula Breast Milk Milk Note the substantial structure of human milk under a microscope; this is due to the compartmentation of the various components such as the nutrients and bioactive substances. This image demonstrates that milk is a living tissue containing about 4000 cells/cubic mm including neutrophils, macrophages, and lymphocytes.Human milk has substantial structure due to the compartmentation of the various components such as the nutrients and bioactive substances. Lipids are a good example of this compartmentation because a milk fat globule is formed as they are secreted from the mammary epithelial cell.Demonstrates that milk is a living tissue containing about 4000 cells/cubic mm including neutrophils, macrophages, and lymphocytes.
42 Human Milk Composition WaterHuman milk is 87% waterProvides sufficient fluid to maintain hydration even in hot climates
43 Human Milk Composition Fat Fat contentg/100ml provides 50% of energy/calories in milkMost variable component of human milkSeparates on standingContains cholesterol, triglycerides, short-chain fatty acids, and long-chain polyunsaturated fatty acidsForemilkMilk that accumulates in breast since previous feedLower fat content (1.5 to 2%) and looks bluish-grayHindmilkMilk that is secreted during a feedHigher fat content (2-3x more than foremilk- 5 to 6%) and looks creamy whiteFrequent shorter feeds can result in poor growth with high milk volumeLipids also aid in protection from infection: milk lipids damage membranes of enveloped viruses
44 Human Milk Composition Fat content increases from the start of a feed (~1.7%)to the end of a feed (~5.5%).Protein content decreases from the start (0.9%) of a feed to the end (0.7%).Foremilk has less fatbut more protein thanhindmilk.
45 Human Milk Composition Fat Lipid ComponentMilk fat globuleForms with lipid secretion from apical mammary epithelial cell and envelopment in its plasma membraneAlso contains proteins, growth factors, and vitaminsMucins on the globule membrane adhere to viruses and bacteria to aid in elimination from bodydiet does not affect amount of fat but does affect types of fat; Triglycerides are the main component of the fats; the lipid proportion provides the essential fatty acidsTerm infants are able to convert long chain polyunsaturated fatty acids to DHA and ARA so the addition of these to term formulas may be unnecessary but is likely useful for preterm infants who cannot convert them.
46 Human Milk Composition Fat Lipid ComponentBile salt-stimulated lipaseActs on triglycerides to produce free fatty acids and 2-monoglyceridesPrevents fatty acids from forming soaps with mineralsResults in superior absorption of fat and mineralsNot present in formulaLipase is heat labile so superior absorption does not occur with processed human milkdiet does not affect amount of fat but does affect types of fat; Triglycerides are the main component of the fats; the lipid proportion provides the essential fatty acidsTerm infants are able to convert long chain polyunsaturated fatty acids to DHA and ARA so the addition of these to term formulas may be unnecessary but is likely useful for preterm infants who cannot convert them.46
47 Human Milk Composition Fat Lipid ComponentAbundance of essential fatty acids (linoleic and linolenic acids)Most exist as triacylglycerols and phospholipids167 fatty acids have been identified in human milkUnique long chain polyunsaturated fatty acids (including omega-3 fatty acids DHA and ARA)Term infants are able to convert long chain polyunsaturated fatty acids to DHA and ARA so the addition of these to term formulas may be unnecessary but is likely useful for preterm infants who cannot convert them.Cholesterol is also present in significant quantitiesdiet does not affect amount of fat but does affect types of fat;Term infants are able to convert long chain polyunsaturated fatty acids to DHA and ARA so the addition of these to term formulas may be unnecessary but is likely useful for preterm infants who cannot convert them.47
48 Human Milk Composition Protein Human milk contains 9g protein/L (whey and casein)Less than in other animal milksWhey proteins consist primarily of α-lactalbumin without β-lactalbuminCow milk whey contains β-lactalbumin to which infants can become intolerantContains less casein than other milksProvides 80% of milk’s nitrogenProtein content declines over 2-4 weeks but then is constant until weaningProtein content varies with time earlier in lactation and 9-12 in later lactation; formula contains 15g/LRemainder of nitrogen comes from non-protein nitrogen sourcesHuman milk has lowest protein of all mammal milks studied; well matched for the developing renal function by placing a lower solute load for excretion on the kidneys
49 Human Milk Composition Protein Colostrum90/10 ratio of whey/caseinMature Milk70/30 ratio of whey/caseinLate Lactation50/50 ratio of whey/caseinCow Milk18/82 ratio of whey/caseinThe whey/casein ratio in human milk decreases from 90/10 in colostrum, to 70/30 in mature milk and to 50/50 in late lactation ( Lawrence, 2005 pgs ). Cow milk contains 18% whey, 82% casein
50 Human Milk Composition Protein Whey (70%)Contains water, electrolytes, and proteinsα-lactalbumin, albumin, lactoferrin, immunoglobulins, enzymes (e.g., lysozyme), growth factors, and hormonesRemains in solution after acidificationLactoferrin, lysozyme, and sIgA resist proteolytic digestion and line the GI tract to provide host defensePresent only in human milkGenerally more easily digested and associated with more rapid gastric emptyingHuman milk contains all the different immunoglobulins (M,A,D,G,E), but sIgA is most common. sIgA is protected from stomach acid so it reaches small intestine intact. Other immunoglobulins, including IgG and IgM, in breast milk also help protect against bacterial and viral infections. Eating fish can help increase the amount of these proteins in your breast milk.Many enzymes are present in milk including some for biosynthesis of the milk in the mammary gland; others aid the infant in digestion of proteins, fats, and carbohydrates to facilitate absorption of milk. Other enzymes transport minerals such as zn, selenium, and magnesium.
51 Human Milk Composition Protein- Whey LactoferrinTransports and promotes the absorption of ironInhibits the growth of iron-dependent bacteria in the gastrointestinal tract such as coliforms and yeastLysozymeEnzyme that protects the infant against E. Coli and SalmonellaPromotes the growth of healthy intestinal flora and has anti-inflammatory functionsSecretory IgAPrimary Ig in breastmilkProtects the infant from viruses and bacteria, specifically those to which the baby, mom, and family are exposedHelps protect against E. ColiLactoferrin transports and promotes the absorption of iron; it also inhibits the growth of iron-dependent bacteria in the gastrointestinal tract. This inhibits certain organisms, such as coliforms and yeast, that require iron.Human milk contains all the different immunoglobulins (M,A,D,G,E), but sIgA is most common. sIgA is protected from stomach acid so it reaches small intestine intact.Secretory IgA is the primary Ig in breastmilk also works to protect the infant from viruses and bacteria, specifically those that the baby, mom, and family are exposed to. It also helps to protect against E. Coli and possibly allergies. Other immunoglobulins, including IgG and IgM, in breast milk also help protect against bacterial and viral infections. Eating fish can help increase the amount of these proteins in your breast milk.Lysozyme is an enzyme that protects the infant against E. Coli and Salmonella. It also promotes the growth of healthy intestinal flora and has anti-inflammatory functions.
52 Human Milk Composition Protein Casein (30%)β-casein forms a soft curd in the infant’s stomach if pH<5Curd is an insoluble calcium caseinate-calcium phosphate complexLow solubility in acidHuman milk casein curds are more easily digested than those in other milksCommercial milk substitutes have been adjusted from predom cows milk casein, but feeding frequency, stools, and stool patterns of formula fed infants are different. Stools are firmer.Many enzymes are present in milk including some for biosynthesis of the milk in the mammary gland; others aid the infant in digestion of proteins, fats, and carbohydrates to facilitate absorption of milk. Other enzymes transport minerals such as zn, selenium, and magnesium.
53 Human Milk Composition Non-protein nitrogen containing compoundsProvide 20% of nitrogen in milkEpidermal growth factorContributes to the development and function of intestinal mucosaTaurineFree amino acid associated with bile acid conjugation and neurotransmissionNucleotidesHave metabolic and immune functionsCarnitineUsed for lipolysis of long-chain fatty acidsSomatomedin-C, Insulin and other peptides
54 Human Milk Composition Carbohydrates When is lactase present in the infant gut?Present in maximal amounts in the intestinal brush border of full term infantsDeficient before 34 wga
55 Human Milk Composition Carbohydrates Lactose (90%) 7.2g/LDisaccharide of galactose and glucose synthesized in the breastImportant source of glucoseImportant source of galactose for galactolipids used in infant brain developmentMonosaccharides, oligosaccharides, and glycoproteins (10%)Oligosaccharides prevent bacteria from adhering to mucosal surfaceOligosaccharides plus glycoproteins = “bifidus factor”Stimulate growth and colonization of newborn’s gut with Lactobacillus bifidus (beneficial bacteria that creates an acidic gut where harmful bacteria cannot survive)Lactose accounts for 40% of the energy intake/calories from breast milkLactobacillus bifidus is nonpathogenic bacteria which protects against invasive enteropathogensBifidus factor supports the growth of lactobacillus. Lactobacillus is a beneficial bacteria that protects the baby against harmful bacteria by creating an acidic environment where it cannot survive
56 Human Milk Composition MineralsContent is similar between mammal milks but concentrations, ratios, and bioavailability are species specificLower quantities results in lower solute load for immature renal systemIron, sodium, potassium, calcium, magnesium, zinc, and small amounts of copper, selenium, chromium, manganese, molybdenum, and nickelZinc and IronWell absorbed from human milkZinc deficiency is rare in breastfed infants whose mothers have adequate Zn intakeBreastfed babies are rarely iron deficient because of this enhanced absorption
57 Human Milk Composition Iron100mcg/L versus formula with 12mg/L50-100% of human milk iron is absorbed4% of iron fortified formula iron is absorbedAbsorption is enhanced by high lactose and vitamin C concentrations in human milkLactoferrin in whey binds ironIncreasing digestion and absorption of ironAlso makes iron unavailable to iron dependent bacteria in gutNormal full-term infants can be exclusively breastfed for 6 months without becoming iron deficientInfants absorb 100% of the iron in breastmilk (<1mg/L) but not all iron in formula which contains 12mg/L
58 Human Milk Composition VitaminsVitamin A, beta carotene, and vitamin EPlentiful in colostrum and early transitional milkVitamin A protects against infection and aids early retinal developmentVitamin E protects red cells against hemolysisVitamin DSufficient only with adequate maternal diet and maternal and infant sun exposureAAP recommends 400 IU/d for all breastfed infants until they are ingesting or exposed to sufficient Vitamin D from other sourcesVitamin KPoorly transported prenatally and also limited in human milkAll newborns must receive Vitamin K at birthVitamin B12Mothers on vegan diets may produce B12 deficient milk so supplements are recommendedBreast milk lacks enough Vit K and Vit D so supplementation is necessary; Vit K is given immediately post partum; human milk averages ~25 IU/L of Vit D; 400 IU per day is recommended, so babies taking less than 16oz formula per day should be supplemented with Vit D.Mothers on vegan diets may produce b12 deficient milk
59 Examples of the Non-nutritional Components of Human milk Antimicrobial factorssecretory IgA, IgM, IgG lactoferrin lysozyme complement C3 leukocytes bifidus factor lipids and fatty acids antiviral mucins, GAGs oligosaccharidesCytokines and anti-inflammatory factorstumour necrosis factor interleukins interferon-g prostaglandins a1-antichymotrypsin a1-antitrypsin platelet-activating factor: acetyl hydrolaseTransporterslactoferrin (Fe) folate binder cobalamin binder IgF binder thyroxine binder corticosteroid binderOtherscasomorphins d -sleep peptides nucleotides DNA, RNAGrowth factorsepidermal (EGF) nerve (NGF) insulin-like (IGF) transforming (TGF) taurine polyaminesDigestive enzymesamylase bile acid-stimulating esterase bile acid-stimulating lipases lipoprotein lipaseHormonesfeedback inhibitor of lactation (FIL) insulin prolactin thyroid hormones corticosteroids, ACTH oxytocin calcitonin parathyroid hormone erythropoietinPotentially harmful substancesviruses (e.g., HIV) aflatoxins trans-fatty acids nicotine, caffeine food allergens PCBs, DDT, dioxins radioisotopes drugsInterferon and fibronectin also have antiviral properties as they enhance the lytic properties of milk leukocytes.Many of the bioactive substances seem to influence neonatal gut maturation and growth by transferring developmental info to the newborn, but the exact roles are still unclear. EGF and TGF alpha are higher in preemie mothers. EGF, TGF alpha, and human milk stimulate fetal small intestinal cell proliferation in vitro with the most prolif following exposure to human milk.
60 Human Milk Composition Passive Immunization via the Enteromammary PathwayMaternal exposureBreast tissue and breastmilkAntigensInfant gutThis image is from the Wellstart intl study module. It illustrates how maternal exposure to antigens (virus and bacteria) results in protection for the infant. The mother ingests the viruses and bacteria which then comes into contact along the gut lining with lymphoblasts that mature into lymphocytes to then migrate into the lymphatic system. The lymphocytes synthesize immunoglobulins. From there, they move into the bloodstream and then into the breast tissue and milk from where they go to the infant.Other mucosal surfacesMaternal gutLymphoblasts mature into lymphocytes that produce immunoglobulins that move into the bloodstreamLymphoblastsBlood streamMesenteric nodeThoracic duct
61 Milk Composition Differences Human MilkCommercial SubstitutesProteinAppropriate (species specific) quality/quantity, easier to digestCorrected in quantity but not in quality (not species specific)FatAppropriate quality/quantity of essential fatty acids, lipase presentLipase absentVitaminsAdequate except for vitamins D and K in some situationsVitamins addedMineralsCorrect amountPartly correctedAnti-Infective propertiesPresentAbsentGrowth FactorsDigestive enzymesHormonesThis table is from the Wellstart international study modules.
62 Thank you for completing Section 2 of Breastfeeding Education for Physicians. To obtain CME credit, please click on the link below, provide your information and complete the post-testhttps://www.surveymonkey.com/s/BreastfeedingSection2