Nutrition During Lactation Flashcards
Breastfeeding recommendations
Exclusive for 6 month, continues in combination with solid food for 12-24 months or beyond as long as mother and baby desire
In Aus- 1-4 breastfed exclusively for 6 months, 70% given formula by 6 months
Anatomy of lactating breast
Lactogenesis- human milk production
Mammary gland- makes and transports milk and includes the alveoli
Alveoli- small sacs lined with milk secreting cells
Secretory cells- cells in alveoli (milk gland) that are responsible for secreting milk components into hollow ducts
Lactiferous sinuses (ducts)- carry milk to outside and between feeds milk is stored
Myoepithelialncell (muscle cell)- line with alveoli and can contract to cause milk to be secreted into ducts
Nerves- allow release of hormones to trigger lactogenesis and let down blood vessels, provide nutrients to make milk
Mammary gland/ breast development- occurs during puberty in preparation for mammary glands for lactation
Hormones contributing to breast development and lactation
-oestrogen
Ductal growth
Important during mammary gland differentiation with menstruation
- progesterone
Alveolar development
Important after onset of menses and during pregnancy
- human growth hormone
Development of terminal end buds- important in mammary gland development
- human placental lactogen- alveolar development, important during pregnancy
Prolactin- alveolar development and milk secretion. Important during pregnancy and breastfeeding from third trimester. Stimulates milk production, released in response to suckling, stress sleep and sex, inhibits ovulation
- oxytocin
Letdown- ejection of milk from myopethelial cells
Important from onset of milk secretion to weaning
Stimulates let down
Released by nipple stimulation
Tingling of breast may occur corresponding to contractions in breast milk duct
Causes uterus to contract, seal blood vessels and shrink in size (return back to normal)
Stages of lactogenesis
Lactogenesis 1- (birth - 2-5 days) milk formation begins
Lactogenesis 2- (2-5 days after birth) increased blood flow to breast milk- comes in
Lactogenesis 3- (approx 10 days after birth) milk composition is stable
If there is no stimulation of the breast in first two weeks, milk supply may become dried out
Human milk composition
Maintained at expense of maternal stores
Changes over a single feeding, over a day, based on age of the infant, presence of infection in the breast, with menses and maternal nutrition status
Colostrum (1st 2-3 days) bright yellow colour, tiny amounts.
- first milk secreted during the first few days postpartum
- produced in small amounts
- low in E, lactose and fat
- higher in protein, minerals and fat soluble vitamins (AEK)
- high in proteins as secretory IgA and lactoferrin
- popular in body builders
Transitional milk (day 7-14) Mature milk (day 14 plus)
Macronutrients in human milk
Maternal diet does not greatly affect concentration of lactose, protein and fat, but can affect concn of some vit and minerals - vit A, thiamine, riboflavin, niacin, biotin, B6, B12, vit C, vit D and iodine
Water major component- isotonic with maternal plasma, provides infants with adequate hydration
Energy- approx 0.65kcal/no (2.8kj/ml)
Energy content may vary with fat, protein and carb comp
Lower energy than formila
Lipids in human milk
Provide half energy of human milk
3-5% concn in mature milk, most variable nutrient
Hind milk> fore milk
Fatty acid profile reflects dietary intake of mother
Very decreased fat diet with adequate CHO and protein, increased milk with medium chain fatty acids
Wt loss- fatty acid profile in fat stores reflected in milk
DHA (doccosahexaenoic acid) essential for regional development and associated with higher IQ scores
Cholesterol higher in human milk than infant formula. Early consumption of cholesterol through breast milk may lower levels in later life
Proteins in human milk
0.8-1% concentration in mature milk
Lower than in cows milk (approx 10vs 30g/L)
Concn maintained at expense of maternal stores
Have antiviral and antimicrobial effects
Caesin is main protein in human milk, facilitates calcium absorption
Whey- soluble protein can have some minerals, hormones, enzymes, immunoglobins and vitamins binding
Non- protein nitrogen - approx 20-25% nitrogen in human milk. Used to nake non essential amino acids, hormones and growth factors
CHO in human milk
Concentration affected by maternal diet
Lactose- dominant CHO, 7% concentration which enhances calcium absorption and is important E source
Olgiosaccharides - medium length CHO, prevent binding of pathogenic infection and diarrhoea, encourage growth of beneficial gut bacteria
Fat soluble vitamins in human milk
- Vit A
Content in colostrum is double than mature milk
Yellow colour from beta carotene
Deficiency remains a problem in developing countries - Vit D
Most as 25-OH2 vit D
Content reflects mothers exposure to sun
Low levels in milk found in hooded women, women living at high latitudes etc
Supplementation- 1 mcg recommended for high risk women
Vit D exclusively BF may need supplements at 2 months - Vit E
Levels linked to milks fat content- not adequate to meet needs of preterm infants - vit K
Approx 5% BF infants at risk of deficiency
Infants who did not receive K injection at birth may be at risk deficiency
Water soluble vitamins in human milk
Content reflective of mothers diet, most likely deficient in B6
- vit B12
Low in women with hypothyroidism, laten pernicious anaemia, are vegans of malnourished, have had gastric bypass surgery, follow GF diets (could be due to poor absorption from microvilli damage)
Minerals in human milk
Contribute to osmolarity
Related to growth of infant
Contraception decreases over first 4 months, except for magnesium
Most have high bioavailability (Mg, Ca, Fe, Zn) exclusively BF infants have low risk of anaemia despite low iron content of human milk
- iodine:
Milk contraception very sensitive to maternal status
NHMRC recommends 150mcg supplement daily
Other trace minerals or altered by mothers diet except fluoride
Taste of human milk
Flavour of foods in mothers diet influences taste of breast milk
Infants seem more interested in mothers milk if new flavour
Exposure to a variety of flavours may contribute to infants interest and acceptance of new flavours in solid food
Benefits of breastfeeding for women
- hormonal
Increased oxytocin stimulates uterus to return to prepregnancy status, decrease post partum blood loss - physical benefits
Contraception and weight loss - Psychosocial benefits
Increased self confidence and bonding with infant - health benefits
Decreased risk T2DM, vreatnahd ovarian cancer, CD, IBD, PPD
Benefits of breastfeeding for infants
- nutritional
Meets all requirements for growth and development
Nutrients balanced
Human milk is isotonic
Meets infant protein needs without overloading the kidney
Contains soft, easily digestible curd
Provides generous amounts of the right lipid
Minerals more bioavailable - immunological
Lower infant mortality
Reduction in SIDS
Reduced infection- gastroenteritis, diarrhoea, RTI, otitis media
Reduced chronic illness- coeliac, IBS, allergies etc
Childhood overweight and obesity - cognitive benefits
Studies show an increase even after adjusting for family and environment as assessed by IQ - socioeconomic
Decrease needs for medical care - analgesic effects
Reduction of infant pain
