Nutrition Through the Life Cycle: Lactation and Infancy

How Human Milk Is Produced

1) suckling by infant 2) simulates hypothalamus 3) initiates the release of hormones prolactin and oxytocin by the pituitary gland 4) prolactin stimulates milk production and oxytocin causes release of milk from storage (breast) "let-down reflex" 5) milk supply for the infant (can be inhibited by nervous tension, lack of confidence, fatigue)

Feeding the Baby

*Birth to 4 months- exclusively breast milk (every 2-3 hours or on demand) *4 to 6 months- introduce semisolid foods but breastmilk still main diet *70% of all mothers breastfeed in the hospital -decreases as infants get older -20-30% still breastfeeding at 4-6 months

Breastmilk Content Not Dependent on Maternal Diet

*Cholesterol *Zinc (if mom deficient, breastmilk will show normal range for 2-3 months) *Calcium (maternal bone loss 3-7%)

Breastmilk Content Dependent on Maternal Diet

*Fatty Acids (type and amount) need LCFA in maternal diet *Vitamin D (time in sun or intake)

Milk Composition ~20 kcal/oz

*Fore milk -first 10-15 min of each feeding -resembles skim milk -17% fat, 74% CHO, 9% protein *Hind milk -resembles cream -66% fat, 28% CHO, 6% protein -released 10-20 minutes into the feeding

Infant Growth and Development

*Rapid Growth rate: -weight= doubles by 4-6 months; triples by 1 year -length= increases by 50% by end of 1st year -brain growth fastest during infancy *inadequate nutrition can inhibit growth

Ability to Breastfeed

*almost all women are physically capable *barriers to breastfeeding: -lack of support & appropriate information -inexperience -requires patience -stress from labor/delivery can delay milk production *when not to: -mom on meds, mom with HIV, TB, undergoing chemo

Watching for Development Landmarks

*birth to 4 months- rooting reflex *4-6 months- neck steady, lower lip control *6-8 months- grasping objects, jaw development

Mature Milk

*easily digested proteins *high long chain omega-3 FA, linoleic acid and cholesterol content (brain development, calories) *higher in carbohydrates, lower in protein/minerals (compared to cow's milk) *less iron than formula (but Lactoferrin instead of Iron Sulfate)

Factors Effecting Lactation

*frequency is biggest determinant ->what if she changes her mind after a month? *volume dependent on mom's hydration *decreased with malnourished mom *oral contraceptive may suppress lactation (6-10 weeks)

Assessment of Growth

*growth charts -comparing with others same age -50th percentile is considered average -BMI for age -Weight for age -Length for age *Height as unique marker

Infancy

*infant loses weight the first few days after birth *0-12 months *normal: 6-8 wet diapers, gaining weight, gaining height, frequent stools

Lactation Nutritional Needs

*milk production requires ~800 kcal/day; mom needs additional 500 kcal/day *increased need for most vitamins/minerals (decrease in need for iron/folate) *mom's diet should limit mercury, pesticides if possible *strenuous anaerobic exercise- lactic acid buildup

Benefits of Breast Feeding

*safest *antibodies-milk-oriented- microbiota (bacteria in gut feed on human milk oligosaccharides) *less likely to overfeed infant *promotes proper jaw and tooth development *promotes uterine wall returning to normal *mom's attitude and support system

Colostrum

*very first milk produced by breasts during late pregnancy and few days after birth *contains antibodies, immune-system cells and lactobacillus bifidus factor *facilitates the passage of 1st stool *higher protein, lower carbs/fat compared to mature milk

At 3 months of age, infants consume about:

0.75 to 1 liter of Human Milk or Formula