Lecture 4: NDD10603
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This document discusses lactation physiology and the development and functional units of the mammary glands. It describes the hormonal control of lactation including prolactin and oxytocin. Key topics covered include the composition and benefits of human milk, breastfeeding positions, attachment, and common breastfeeding conditions such as sore or inverted nipples. The document provides an overview of the nutritional needs for lactation and factors that can influence breast milk supply and demand.
Lecture 4: NDD10603
- 1. NDD10603 Lecture 4 Nutrition During Lactation
- 2. Introduction • Information beneficial to health care professionals to promote breastfeeding is included:
- 3. Lactation Physiology Mammary gland Source of milk for offspring, the breast Alveoli Rounded or oblong shaped cavity present in breast Myoepithelial cells Line the alveoli & can contract to cause milk to be secreted into ducts Lobes Rounded structures of mammary glands Oxytocin Hormone produced during letdown that causes milk to eject into ducts Prolactin A hormone necessary for milk production Lactogenesis Term for human milk production Secretory cells Cells in acinus (milk gland) that are responsible for secreting milk components into ducts
- 4. Breast of a Lactating Female
- 5. Functional Units of the Mammary Glands
- 6. Mammary Gland Development • During puberty, the ovaries mature with increases in estrogen & progesterone • Primary hormones contributing to breast development and lactation are: – Estrogen —Progesterone – Human growth hormone —Prolactin – Human placental lactogen —Oxytocin
- 7. Mammary Gland Development HORMONE ROLE STAGE
- 8. Mammary Gland Development • Estrogen & progesterone increase during puberty • Levels of both hormones increase dramatically to prepare mammary glands for lactation
- 11. Hormonal Control of Lactation PROLACTIN Stimulates milk production Released in response to suckling, stress, sleep, & sexual intercourse OXYTOCIN Stimulates letdown Tingling of the breast may occur corresponding to contractions in milk duct Causes uterus to contract, seal blood vessels, & shrink in size
- 13. Human Milk Composition • Human milk is the only food needed by the majority of healthy infants for ~ 6 months – It nurtures & protects infants from infectious diseases • The composition changes over a single feeding, over a day, based on age of the infant, presence of infection in the breast, with menses, & maternal nutrition status
- 14. Colostrum The first milk secreted during the first few days postpartum
- 15. Colostrum Composition of 100 mL colostrum (days 1-5 postpartum) and mature milk (day 15 postpartum)
- 16. Water and Energy in Human Milk WATER – Major component in human milk – Isotonic with maternal plasma ENERGY – ~0.65 kcal/mL – Calories may vary with fat, protein and carbohydrate composition – Lower in calories than human milk substitute (HMS)
- 17. Lipids in Human Milk • Lipids—provide ½ the calories in human milk • Effect of maternal diet on fat composition – Fatty acid profile reflects dietary intake of mother – Very fat diet with adequate CHO & protein, milk is in medium-chain fatty acids
- 18. DHA, Trans Fatty Acids, and Cholesterol in Human Milk DHA (docosahexaenoic acid) Essential for retinal development. Associated with higher IQ scores. Trans fatty acids Present in human milk from maternal diet. Cholesterol Higher in human milk than HMS. Early consumption of cholesterol through breast milk appears to be related to lower blood cholesterol levels later in life.
- 19. Proteins in Human Milk Total proteins Lower than in whole cow’s milk (0.32 vs. 0.96 g/fl oz) Have antiviral & antimicrobial effects Casein Main protein in mature human milk Facilitates calcium absorption
- 20. Proteins in Human Milk Whey A soluble protein that precipitates by acid or enzyme Some minerals, hormones & vitamin binding proteins are part of whey Includes lactoferrin, an iron carrier Non-protein nitrogen ~20-25% nitrogen in human milk Used to make non- essential amino acids
- 21. Milk Carbohydrates Lactose Dominant CHO Enhances calcium absorption Oligosaccharides A medium-length CHO Prevent binding of pathogenic microorganisms to gut, which prevents infection & diarrhea
- 22. Fat-Soluble Vitamins in Human Milk Vitamin A Content in colostrum is ~double that of mature milk Yellow color from beta-carotene Vitamin D Most as 25-OH2 vitamin D and D3 Content reflective of mother’s exposure to sun
- 23. Fat-Soluble Vitamins Vitamin E Level linked to milk’s fat content Level not adequate to meet needs of preterm infants Vitamin K ~5% of breastfed infants at risk for K deficiency based on clotting factors Infants who did not receive K injection at birth may be deficient
- 24. Water-Soluble Vitamins in Human Milk Water soluble in general Content reflective of mother’s diet or supplements Vitamin most likely to be deficient is B6 Vitamin B12 and folate Bound to whey proteins Low B12 seen in women who: Have hypothyroidism or latent pernicious anemia Are vegans or malnourished Have had gastric bypass
- 25. Minerals in Human Milk • Minerals contribute to osmolality – Content related to growth of infant – Concentration decreases over first 4 months, except for magnesium • Bioavailability – Most have high bioavailability – Exclusively breastfed infants have very low risk of anemia despite low iron content of human milk
- 26. Minerals in Human Milk • Zinc – Bound to protein & highly available – Rare defect in mammary gland uptake of zinc may cause zinc deficiency that appears as diaper rash • Trace minerals – Copper, selenium, chromium, manganese, molybdenum, nickel, fluoride – In general, trace minerals are not altered by mother’s diet, except fluoride
- 27. Taste of Human Milk • Flavor of foods in mother’s diet influences taste of breast milk – Infants seem more interested in mother’s milk if flavor is new • Exposure to a variety of flavors may contribute to infant’s interest & acceptance of new flavors in solid foods
- 28. Benefits of Breastfeeding for Women
- 30. Benefits of Breastfeeding for Infants 1. Nutritional benefits – Widely recognized – HMS (Human Milk Subs) use human milk as a standard – Nutrients are balanced – Human milk is isosmotic – Meets infants’ protein needs without overloading the kidneys – Contains soft, easily digestible curd – Provides generous amounts of the right lipids – Minerals more bioavailable
- 31. Benefits of Breastfeeding for Infants 2. Immunological benefits – Lower infant mortality in developing countries – Fewer acute illnesses 3. Reductions in chronic illnesses – Reduce risk of celiac disease, IBS, leukemia – Reduce risk of allergies and asthmatic disease 3. Breastfeeding & childhood overweight – Typically breastfed infants are leaner at 1 year of age
- 32. Benefits of Breastfeeding for Infants 5. Cognitive benefits – Studies show an increase in cognitive ability even after adjusting for family environment 5. Analgesic effects – Reduction of infant pain 5. Socioeconomic benefits – Decreased need for medical care
- 33. Breast Milk Supply and Demand • Can women make enough milk? Milk synthesis is related to: How vigorously an infant nurses How much time the infant is at the breast How many times per day infant nurses
- 34. Breast Milk Supply and Demand • The size of the breast does NOT limit a woman’s ability to nurse • Is feeding frequency related to the amount of milk a woman makes? – Rate of milk synthesis is variable between breasts & between feedings
- 35. Breast Milk Supply and Demand • Pumping or expressing milk – Several different methods are available • Manually • Hand pumps • Commercial electric pumps • Hospital grade electric pumps – To stimulate adequate milk may require 8-12 expressions per day
- 36. Positions for Breastfeeding BREASTFEEDING POSITION FOOTBALL SIDELYING CROSSCRADLE CRADLE
- 37. Attachment
- 38. Attachment
- 39. The Breastfeeding Infant • Reflexes – Gag reflex—prevents infant from taking food and fluids into lungs – Oral search reflex—infant opens mouth wide when close to breast & thrusting tongue forward – Rooting reflex—infant turns to side when stimulated on that side • Also requires appropriate positioning , adequate letdown and milk production
- 41. The Breastfeeding Infant Feeding frequency • 10-12 feedings/day are normal for newborns • Stomach emptying occurs in ~1½ hours
- 42. Identifying Breastfeeding Malnutrition • Normal weight loss for newborns – ~7% of birthweight in 1st week – Weight loss of 10% needs evaluation by lactation consultant • Malnourished infants become sleepy, non- responsive, have a weak cry, & wet few diapers – By day 5 to 7, infants should have 6 wet diapers & 3-4 soiled diapers
- 43. Tooth Decay • Caries can occur in children who are breastfed • Risk factor is frequent nursing at night after 1 year • All children should be seen 6 months after 1st tooth erupts or at 1 year of age
- 44. Energy and Nutrient Needs for Lactation • Energy needs vary by activity level • RNI is 500 kcal/day for the 1st 6 months A single recommendation for energy needs could never address all of the individual variation in energy needs
- 45. Protein • Protein requirements (15-20%) – +20 g for the 1st 6 months – +15 g for the 2nd 6 months
- 46. Maternal Energy Balance and Milk Composition • Protein-calorie malnutrition – Results in reduction in milk volume but not quality • Weight loss during breastfeeding – the caloric DRI assume a loss of 0.8 kg/month – Most women do not reach pre-pregnancy weight by 1 year after birth – Modest or short-term energy reductions do not decrease milk production
- 47. Other Factors of Maternal Diet • Infant Colic – Defined as crying for more than 3 hours a day – no medical cause – Components of maternal diet may be related to infant colic – More likely with • Cow’s milk, onions, cabbage, broccoli, & chocolate
- 48. Barriers to Breastfeeding Initiation Time & social constraint Embarrassment Lack of confidence Concern about diet & health Fear of pain
- 49. Common Breastfeeding Conditions • Sore, flat or inverted nipples • Letdown failure • Hyperactive letdown • Hyperlactation • Engorgement • Plugged duct • Mastitis (Infection) • Low milk supply
- 50. Common Breastfeeding Conditions • Sore, flat or inverted nipples • Letdown failure • Hyperactive letdown • Hyperlactation • Engorgement • Plugged duct • Mastitis (Infection) • Low milk supply
- 51. Condition: Sore nipples • May be prevented by proper positioning of baby on breast • The areola should be in the baby’s mouth with tongue extended against lower lip
- 52. Condition: Flat or Inverted Nipples • This should not impact breastfeeding if the latch is correct. • If difficult to latch: – Mother may roll her nipple between her fingers – Or use a breast pump prior to feeding • Helps to draw out the nipple
- 53. Condition: Letdown Failure • When milk does not eject from the breast • Very uncommon • Oxytocin nasal spray may be prescribed • Relaxation techniques may help reduce problem
- 54. Condition: Hyperactive Letdown • Streams of milk come from breast • If too active, may cause infant to choke while nursing • Management: – Wait for the milk flow to slow down before putting the infant to the breast – Mother may express milk until the flow slows then allow infant to nurse
- 55. Condition: Hyperlactation • Occurs when milk volume produced exceeds intake of the baby – Symptoms in mother: • Breasts not drained completely • Chronic plugged ducts • Leaking between feedings • Pain with letdown or deep in breast – Symptoms in baby: • Spitting up, poor weight gain • Difficulty maintaining latch
- 56. Condition: Hyperlactation • Management: – Reduce production • Nurse baby on one side only and express for comfort on the other • Cabbage leaves may be used to decrease production
- 57. Condition: Engorgement • Breasts are overfilled with milk • Results when supply- and-demand process is not yet established and milk is abundant • Best prevention: nurse frequently— newborns may nurse every 1 to 2 hours
- 58. Condition: Plugged Duct • Caused by milk staying in the ducts • Painful knot may form in breast • Treated by massage and warm compress • Prevented by complete emptying of breasts and changing position of infant while feeding
- 59. Condition: Mastitis (Infection) • Mastitis is inflammation of the breast – May be infective or non-infective • Occurs in 3 to 20% of breastfeeding women • Most common at 2-6 weeks postpartum
- 60. Condition: Mastitis (Infection) • May result from: – Sore and cracked nipples – Blood borne source of bacterial infection – Missing a feeding resulting in engorgement, then plugged duct may precipitate engorgement
- 61. Condition: Low Milk Supply • Most common reason for cessation of breastfeeding – May be real or may be perceived • Causes: – Insufficient breastfeeding or pumping – Ineffective emptying – Stress • Management – Nurse or pump every 2-3 hours – Drugs or herbs may be prescribed • Galactogogue, Metoclopromide, Fenugreek
- 62. Neonatal Jaundice and Kernicterus • Jaundice—a yellow color of the skin seen in about 60% of full-term & 80% of preterm infants (AKA hyperbilirubinemia) • If not resolved, the elevated bilirubin can cause permanent neurological damage • It is the most frequent cause for hospital readmission for newborns
- 63. Bilirubin Metabolism • Bilirubin—a pigment produced as heme from red blood cells (RBC) break down • Usually processed by the liver and excreted in the baby’s stool • Newborn’s liver not fully mature so jaundice is common during first few days of life • Color appears first in the face & upper body then progresses downward toward the toes
- 64. Bilirubin Metabolism • In the fetal state, high levels of hemoglobin were needed to carry oxygen delivered by the placenta • At birth, infants have very high levels of hemoglobin and hematocrits of 50% to 60% • As infant breathes on his own, high hemoglobin is not needed, so RBC begin to break down
- 65. Physiologic versus Pathologic Newborn Jaundice PHYSIOLOGICAL •Begins after the 1st day of birth rising steadily with peak ~ day 6-7 •Bilirubin <12 mg/dL •Condition resolves within a few days •Cause: normal heme breakdown PATHOLOGICAL •Begins within 1st day after birth rises rapidly & lasts longer •Bilirubin >8 mg/dL in 1st day •Medical intervention with phototherapy •Cause: various pathological conditions
- 66. Treating Jaundice • The AAP guidelines recommend phototherapy using fluorescent lights • Light is absorbed in bilirubin changing it to a water-soluble product that can be excreted via the kidneys • AAP guidelines encourage continuation of breastfeeding
- 67. Breastfeeding Multiples • Breastfeeding twins, triplets & quadruplets is possible – Main obstacle is the time & fatigue of mother • Frequent nursing increases milk supply • Parents of multiples need support in: – Organization – Feeding – Individualization – Stress management
- 68. Infant Allergies • Exclusive breastfeeding for ≥4 months protects against allergies, ectopic dermatitis & wheezing • Development of food allergies influenced by numerous factors: – Genetics, duration of breastfeeding, time of introduction of other foods, maternal smoking, air pollution, exposure to infectious disease, maternal diet and immune systems • Consumption of omega-3 fatty acids by lactating mother may protect against Allergies
- 69. Late-Preterm Infants • Infant born 34 to 37 weeks • May have subtle immaturity making breastfeeding difficult • Complications include: – Cardio-respiratory instability, poor temperature control, lower glycogen & fat stores, immature immune system, weak suck- swallow coordination
- 70. Human Milk Collection and Storage “Human milk is the most appropriate food for infants and is also used as medical therapy for older children and adults with certain medical conditions. Human milk has a long history and proven track record both as nutrition and therapy.” – Human Milk Banking Association of North America
- 71. Human Milk Collection and Storage
- 72. Human Milk Collection and Storage
- 73. SELF-STUDY • Three Stages of Lactogenesis • The Letdown Reflex • Benefits of Colostrum • Breastmilk vs Formula Milk
Editor's Notes
- #6: Alveoli in mammary glands are the functional units Each is composed of secretory cells with a duct in the center Myoepithelial cells, that line the alveoli, contract during letdown causing milk ejection