Lactation Flashcards
Alveoli
Rounded or oblong shaped cavity present in breast where milk is stored, lined with lactocytes
Secretory cells
Cells in acinus (milk gland) that are responsible for secreting milk components into ducts
Prolactin
Stimulates milk production
Released in response to suckling
Oxytocin
Stimulates letdown
Induces contractions in milk ducts
Causes uterus to contract, seal blood vessels, & shrink in size
Colostrum
Milk produced in the first few days
Rich in immunologic components such as secretory IgA, lactoferrin, leukocytes, as well as developmental factors such as epidermal growth factor.
Relatively low concentrations of lactose
Primary functions is to be immunologic and trophic rather than nutritional.
Levels of sodium, chloride and magnesium are higher
Levels of potassium and calcium are lower
in colostrum than later milk
Carbohydrates in BM
Lactose
Dominant carbohydrate
Enhances calcium absorption
Higher concentrations with greater volume of milk
Oligosaccharides
Second largest carbohydrate component
Prevent binding of pathogenic microorganisms to gut, which prevents infection & diarrhea
HMO structure different from those added in formulas and Bovine.
Lipids in BM
Lipids—provide ½ the calories in human milk
Concentration changes over course of the feeding
Foremilk has lower fat than hindmilk
3.2 to 3.6 g/dL
Maternal diet changes fat composition of milk
Fatty acid profile reflects dietary intake of mother
DHA (docosahexaenoic acid)
Increased with maternal supplementation
Essential for retinal development
Associated with higher IQ scores in infant
Trans fatty acids
Present in human milk from maternal diet
Cholesterol
Higher in human milk than formula
Early consumption of cholesterol through breast milk appears to be related to lower blood cholesterol levels later in life ( Wong et al 1993)- Better regulation of endogenous synthesis via HMG CoA
Protein in BM
Casein
Predominant type of protein
Facilitates calcium absorption
Whey
A soluble protein that precipitates by acid or enzyme
Some minerals, hormones & vitamin binding proteins are part of whey
Non-protein nitrogen (e.g., urea, free amino acids)
~20-25% nitrogen in human milk
Used to make non-essential amino acids
Lower than in whole cow’s milk
Have both nutritive and non-nutritive roles
Antiviral
Antimicrobial
Enzymes to protect against inflammation
Concentration more affected by age of infant than by maternal diet
Preterm milk is higher in protein and fat
Glutamate in BM
Provides ketoglutaric acid for the citric acid cycle, possibly acting as a neurotransmitter in the brain, and serving as a major energy substrate for intestinal cells.
Regulates intakes- High levels of free glutamate in breast milk and extensively hydrolyzed formula are responsible for the lower daily intakes of these diets.
Very low-birth weight infants receiving Glutamine supplementation have less tissue catabolism and enhanced gluconeogenesis- established
Fat soluble vitamins in BM
Vitamin A
Content in colostrum is ~double that of mature milk
Yellow color from beta-carotene
Vitamin D
Most as 25-OH2 vitamin D
Content reflective of mother’s exposure to sun and diet
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 ( Need it because of sterile gut)
Water soluble vitamins in BM
Content reflective of mother’s diet
Vitamin most likely to be deficient is B6, 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
Minerals in BM
Minerals contribute to osmolality
Content related to growth of infant
Concentration decreases over 1st 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
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
Breastmilk Jaundice
Onset later than physiological jaundice—typically peaks 7th to 10th day
1/3 of breast-fed infants are jaundiced at 3 weeks
Cause is unknown
Thought that more bilirubin is reabsorbed due to factors in breast milk that promote its absorption
Typically resolves itself but in severe cases is treated like regular physiological jaundice
