Nutrition During Lactation Flashcards
When did breastfeeding rates start to decline?
1950s and 1960s
then dramatically in the 1970s
declined until the early 1990s
What demographic factors are associated with longer duration of breastfeeding?
higher education higher SES western region married being older white, hispanic/latino
What timeframe is considered early postpartum?
first 7 days
What is the mammary gland?
source of milk for offspring
What are alveoli?
functional unit of mammary gland - secretes milk
cluster of cells with a duct in the center
round or oblong shaped cavity in the breast
What are secretory cells?
responsible for secreting milk components into the ducts
What are myoepithelial cells?
line the alveoli
contract to cause milk to be secreted into the ducts
What is oxytocin?
hormone
letdown - eject milk from gland (acinus) into milk ducts
stimulated by sucking and nipple stimulation
causes uterus to contract, shrink and seals blood vessels
How do mammary glands develop?
during puberty
increased release of E and P from ovaries
hormones govern breast development
develops lobes, ducts and alveoli
usually complete within 12-18 months of menarche
What happens as the ductal system matures?
cells that secrete milk develop
nipple grows
nipple pigmentation changes
fibrous and fatty tissues increase around ducts
What happens during pregnancy to prepare for breastfeeding?
luteal and placental hormones
estrogen simulates dev. of glands that make milk
P allows tubules to elongate and epithelial cells to duplicate
What is lactogenesis?
production of milk
occurs in 3 stages
What is lactogenesis 1?
begins during last trimester, extends through first few days postpartum
milk begins to form
lactose and protein content of milk increases
What may impact lactogenesis 1?
premature delivery
method of delivery
other factors
What is a full milk supply?
25-35 ounces per day
What is lactogenesis 2?
2-5 days postpartum
increased blood flow to the mammary gland
onset of copious milk secretion
significant changes in composition and quantity over first 10 days
What is lactogenesis 3?
about 10 days postpartum
composition becomes stable
What is prolactin?
hormone
stimulates milk production, inhibits ovulation
sucking stimulates secretion of prolactin
also stimulated by: stress, sleep, intercourse
3rd trimester to weaning (activity inhibited during pregnancy)
What hormones are necessary for establishing and maintaining milk supply?
prolactin and oxytocin
What hormones contribute to breast development and lactation?
estrogen, progesterone, human growth hormone, human placental lactogen, prolactin, oxytocin
What are the pathways for secretion of milk components?
- made in the secretory cells
- passive diffusion through alveolar cell membranes
- from mother’s blood
What causes letdown?
suckling, sexual arousal, thinking about nursing, hearing a baby cry, etc.
What is the purpose of human milk?
nurture the infant
protect from infectious and certain chronic diseases
What can cause the composition of human milk to change?
age of infant gestation at delivery presence of infection in breast menses maternal nutritional status
What is colostrum?
first milk produced during lactogenesis 2
thick, often yellow
has a lot of immunoglobulin
How does colostrum differ from mature milk?
higher in protein, lower in fat and CHO lower in calories higher in mononuclear cells (immune) higher concentrations of Na, K, Chloride some proteins not present higher in Vitamin A (about double)
What are the components of human milk?
water, energy, protein, fat, minerals, nutrients, sugars, carbs
Which infants consume more calories?
non-breastfed
What are the PRO, CHO, FAT shares of energy in human milk?
FAT - 50% (assume 20 kcal per ounce)
PRO - 1%
CHO - 49%
How does the maternal diet effect fat composition?
diet reflects the fatty acids
if she’s losing weight, fat stores reflect the fatty acids
if her diet is low fat, but calorie sufficient, there are more medium-chain fatty acids
DHA levels increased by supplementation
reflects trans-fats
What are the benefits of DHA in breastmilk?
retinal development
associated with higher IQ scores
only found in some formulas
especially important to preterm infants
Which infants consume more cholesterol?
breastfed
early consumption appears to lower levels in later life
What impacts protein concentration?
age of infant rather than maternal intake and status
What are the values of human milk proteins?
antiviral and antimicrobial effects
might facilitate prevention of inflammation