Exam 3- Infancy Flashcards
A term infant is __% body fat and a 1 yr old is ___% body fat
16, 25
From 1 yr to adulthood the ___ decreases and the ____ increases
ECF, ICF
Energy requirements in children determined by
Determined by age, size, growth rate and PA
Calorie needs at 3 mo, 2 yr, 8yr, 12yr
100, 85, 75, 60 kcal/kg/day (adults are 25)
Optimal Indicator of Nutritional Status:
growth
Among growth charts what is a cause of concern?
If a child jumps 2 or more lines
Growth charts used for birth to 24 months
length, weight, head circumference, weight for length
Growths charts used 2-20 years
BMI for age, height, weight
Infancy- key concepts
- most rapid growth
- Nutritional requirement on the basis of per kg of body weight is highest of all life stages
- Dramatic development of feeding skills occurs- from reflex sucking at birth to eating at the table by 12 mo
- weight doubles by 4 mo and triples by 12 mo, length increases by 50% at 12 months and head circum by 40%
Newborn’s GI System: motility
Coordinated breathing, sucking & swallowing
GI motility:
- esophagus: lower esophageal sphincter (LES) is weak
- stomach: gastric capacity & emptying: small and fast
- small intestine transit time: longer
- large intestine transit time: shorter
Digestive enzymes
- amount
- activity
Excretion of undigested products
Newborn’s GI System: Digestive enzymes
Digestive enzymes
- amount: most are lower disaccharidases and intestinal mucosal peptidases
- activity: trypsin has reduced activity
Excretion of undigested products
Newborn’s Renal Function
- Kidneys immature at birth
- Need more water to excrete a given amount of “waste”
- potential renal solute load: comes from protein, Na, Cl, K and P, increase PRSL and increase burden on kidneys *why infants can’t drink cows milk
Psychosocial Development: main point
Feeding is the fundamental interaction from which the relationship between parents and infants evolves and the infants psychosocial development proceeds
Temperament
- Inherited pattern of physiologic and behavioral reactions tosituations.
- Components commonly include activity level, rhythmicity, approach, adaptability, intensity, mood, persistence, distractibility, and threshold
- classified as “Easy”, “Average”, “Difficult”
Development of feeding skills: 1-3 mo
suck and swallow
rooting
tonic neck reflex
head control is poor
Development of feeding skills: 4-6 mo
Rooting reflex fades
bite reflex fades
tonic neck reflex fades
Development of feeding skills: 7-9 mo
Gag reflex fades
Choking reflex can be inhibited
Develop rotary chewing
Development of feeding skills: 10-12 mo
Bites and grasps
Drink from cup
Lick food
Finger feeds with pincer grasp (rather than whole hand)
Key tips to breastfeeding
Let baby decide when and how much to eat
Respond to baby’s cues- crying and fussing
DRI – Approach for Infancy
Basic approach
- 2 stages: 0-6 mo and 7-12 mo
- energy based off total energy expenditure + growth
0-6 mo DRI
0-6 mo: all AIs, no EAR/RDA
- Based on breast milk intake of 780 ml/day
- AI for all nutrients
0-7 mo DRI
- Based on breast milk intake of 600 ml/day plus solid foods
- EAR/RDA for protein and iron
- AI for remaining nutrients
Energy requirement percentages
Growth: ~40% at birth, ~10% at 6 mo ~3% at 12 mo BMR: ~50% at birth, ~60% at 6 mo ~70% at 12 mo
Growth factor, adds how many calories?
0-3: 175
4-6: 56
7-12: 22
2ndary indicator of getting enough energy
Diapers- 3-4 stools per day, 5-6 wet diapers per day. Yellow, seedy, semisolid stool
Infants require a larger percentage of their calories to come from ___, ____ and ___
Protein, linolenic acid (precursor of DHA), linoleic acid
Macronutrient Contents in Human Milk - Carbohydrates
Types: lactose and oligosaccharides
Lactose:
- de novo synthesis in the mammary gland from galactose & glucose by enzymes that require a-lactalbumin as co-factor
- stimulates gut microorganisms
- enhances Ca and other mineral absorption
Oligosaccharides:
- function as resistance factors
Macronutrient Contents in Human Milk - Protein
-Colostrum contains higher protein than mature human milk
-Major proteins in human milk: casein and whey
Casein: 20-30% in colostrum, ~45% in mature human milk - form hard curds in the stomach (lowPH)
Whey: 70-80% in colostrum, ~55% in mature human milk - proteins that remain soluble after casein precipitates
- form softer curds in the stomach, easier to digest
- major whey protein: lactalbumin, synthesized de novo - other whey proteins: immunoglobulins, lactoferrin & other resistance factors
Non-protein nitrogen: urea & nucleotides
- account for 1/4 of total nitrogen in human milk
Macronutrient Contents in Human Milk - Fat
- Colostrum contains less fat than mature human milk
- Within each feeding, fat content is lower in foremilk than hindmilk
- > 90% fat in human milk is triglycerides (TG)
- unique TG structure: palmitate (16:0) in sn-2 position, easier to absorb than stereate (18:0)
Macronutrient Contents in Human Milk - Fat - FA profile
FA profile
- rich in PUFA; more EFA [linoleic (C18:2, n-6) and linolenic (C18:3, n-3)] than cow’s milk
- also contains EPA (C20:5, n-3) and DHA (C22:6, n-3) (cow’s milk does not contain DHA)
DHA: essential for brain and retina development
Macronutrient Contents in Human Milk - Fat - Cholesterol
- present in human milk but not in cow’s milk
- stimulate enzymes for cholesterol degradation
DHA in Infancy
-DHA accumulates in brain and retina during 0-2 yr
-DHA synthesis from linolenic acid is limited, dietary supply is needed
-Human milk contains DHA, cow’s milk does not
DHA supplementation in maternal diet during breastfeeding
- increased maternal blood DHA, breast milk DHA and infant’s blood DHA
- neural function and visual acuity did not differ
DHA supplementation in infant formula
- increased infant’s blood DHA
- neural function/visual acuity are better at age 1 y but not 3 y
Micronutrient Requirement in Infants: Iron
Fe metabolism in infants
- very high Hgb level at birth, decline to adult level by 6 mo
- Birth to 6 mo: req met by Fe store and recycled Fe from hemoglobin
- after 6 mo: Fe store depleted; rely on dietary intake
Iron DRI, 0-6 mo
- AI = 0.27 mg/d, based on breast milk content
Iron DRI, 7-12 mo
EAR = (basal loss + Fe deposition)/10% absorption
= (0.26 mg + 0.43 mg)/10% = 6.9 mg/d
RDA = 11 mg/d
AAP recommendations on iron supplementation
- BF infants: begin at age 4-6 months
- FF infants: not needed bc Fe-fortified formula
Micronutrient Requirement in Infants: Vitamin D
- breast milk contains little vitamin D
- vitamin D AI established based on maintaining adequate serum 25(OH)D
-AI = 400 IU for both 0-6 and 7-12 mo
AAP recommendations:
-BF infants: supplement at birth
-FF infants: no supplement needed, fortified
Micronutrient Requirement in Infants: Fluoride
- 0-6 mo: AI = 0.01 mg/d, based on breast milk content (no correlation between Fl intake at this age & dental carries)
- 6-12 mo: AI = 0.5 mg/d, based on protection for dental caries
- AAP recommendations:
BF infants: supplement beginning at 6 mo
FF infants: supplement beginning at 1 mo if water used to prepare formula is not fluoridated
Micronutrients in Human Milk: Vitamins
- concentrations vary depending on maternal nutritional status and vitamin contents in maternal diets
- vitamin D in human milk insufficient to meet infant requirement, supplementation (400 IU/day) should be given shortly after birth
Micronutrients in Human Milk: Minerals
- concentrations lower than cow’s milk but high bioavailability- advantage to newborn’s immature renal system
e. g., Zn: 10% bioavailable in cow’s milk; 49% bioavailable in breast milk - Fe in human milk insufficient to meet infant requirement, supplementation needed beginning at 4 months of age
Non-nutritional Beneficial Compounds in Human Milk
Resistance (anti-infective) factors:- Immunoglobulins: 90% are secretory IgA (sIgA); colostrum contains the highest content of IgA
- Bifidus factor
- Binding proteins: lactoferrin (binds iron) & B12-binding protein
Enzymes
- Digestive enzymes:, e.g., lipases, amylase
- Lysozymes
Cellular components
- Macrophages, T- and B-lymphocytes, neutrophils
Hormones and growth factors
Effect of Maternal Nutritional Status on Human Milk Production and Composition
- Moderate calorie deficit, e.g., caloric intake at 80% of requirement does not reduce vol of breast milk production or nutrient content
- More severe protein-energy malnutrition, e.g., caloric intake <60% of requirement decreased the vol of milk produced but does not decrease caloric density or nutrient content
- Variation in maternal diet does not influence breast milk concentrations of protein, CHO, total fat and most minerals
- Variation in maternal diet does influence breast milk concentrations of: FA profile and vitamins (esp water soluble)
Alternative to Breast Milk – Infant Formula
Cow’s milk NOT appropriate
- too much pro, Na, Cl, k and P
- low EFA, no DHA, vit A, D, E and iron
- GI blood loss found in infants fed cow’s milk
Infant formula kinds
- cow’s milk based
- soy-based
- special formulas (for infants with special health care needs)
Cow’s Milk Based Infant Formula
decreasing protein amount & modifying type of protein - decrease casein, increase whey; casein/whey ratio vary among brands
-adding carbohydrate
- to compensate for reduced protein
-changing fat composition
- remove milk fat (decrease SFA), add vegetable oil (increase UFA)
-add EFA and DHA
-decrease Ca, P, Na, Cl, K; increase vitamin A, C, D, E, iron
Two subtypes of cow’s milk based formula on the market
-low-iron or high-iron (iron-fortified)
(1-1.5 mg/L) (10-12 mg/L)
AAP recommends iron fortified cows milk formula
Soy Based Infant Formula
- For infants with galactosemia, congenital lactose deficiency and cows milk protein allergy
- Made with soy protein isolate + corn syrup + veg oil
- major CHO in corn syrup is glucose polymers
- supplemented with methionine (limiting AA in soy)
- higher protein and mineral content than cow’s milk formula b/c lower protein quality & mineral bioavailability - all soy formula are high-iron (iron-fortified); no low-iron soy formula
- higher PRSL than cow’s milk formula
- Not recommended by AAP for healthy term infants
Introduction to Solid Foods: When?
No earlier than 4-6 months, why?
- Nutritionally not necessary until then
- developmentally not ready (need to lose tongue reflex)
- Earlier intro. increases probability of developing allergies and eczema
- earlier intro doesn’t help baby sleep through the night
Major purpose of solid foods
- to develop feeding skills
- NOT to provide major source of nutrition; breast milk/formula remains the primary source of nutrition up to age 12 mo
Feeding Skills & Solid Food Introduction: 6 mo
6 mo- intro to solid foods
- rooting and extrusion reflexes fades
- open mouth for foods
- able to sit up with support
Feeding Skills & Solid Food Introduction: 7-9 mo
Finger foods, self feeding
- rotary chewing begins; munching more efficient
- pincer grasp develops; holds bottle & sippy cup
- able to sit without support
Feeding Skills & Solid Food Introduction: 9-12 mo
Table Foods and self spoon feeding
- develops interest to self-feed with spoon/fork (grasp bottle and utensils)
- begins to drink from an open cup, although not mastered until toddler ages
When to wean breast milk/formula
At 12 mo, switch to whole milk (not fat free)
Guidelines for Introducing Solid Foods: frequency
introduce one, single-ingredient food at a time, wait 3-7 days before introducing another one
Guidelines for Introducing Solid Foods: order
- First: Fe-rich food (meat) and Fe-fortified food (infant cereal)
- Second: vegetables and fruits (provide new flavors micronutrients)
Guidelines for Introducing Solid Foods: Form and texture for spoon feeding
thick liquid to mashed/ground to chopped
Guidelines for Introducing Solid Foods:
If a food is rejected at the first time, offer it again
-may take 10-12 attempts
Introduce as many varieties as possible between 6-12 mo
Let the baby decide when and how much to eat
- infants have innate ability to regulate energy balance
- Goal is to gradually increase solids and decrease formula/breast milk(general guideline: aim at less thab 32 oz at 6 mo, less than 24 oz by 12 mo)
Baby Led Weaning
Baby feeds themselves all foods from the beginning of complimentary feeding
-skip purees and spoon feeding, stick shaped pieces
-Parent decides “what;” baby decides if they will eat, “how much,” and “how quickly”
-Encourages responsive feeding practices
Potential pros: may lead to improved eating patterns, healthier weight, greater food acceptance
Potential cons: risk of choking, inadequate iron intake, inadequate energy intake
5 important points for safety:
◦Make sure the baby is sitting upright ◦Limit distractions ◦Baby is ready to start eating ◦Don’t put food in baby’s mouth ◦Offer appropriate foods
Nutritional Assessment for Infants
growth is the most important indicator of nutritional status in infants (and children)
Growth
- increase in body mass in set patterns
- growth rate: differs by stage of childhood
- measures of growth: weight, weight for length, length, head circumference, BMI
Tools to assess growth:
growth charts
- Sources of data for growth charts
- Age 0-2 years: WHO (breastfed infant based)
- Age 2-20 years: CDC (US data)
- Specific for gender and age
Length, weight & head circumference-for-age percentiles
- indicate how the baby’s length, weight and head circumference compared to other infants of same age
Weight-for-length percentile
- indicate how the baby’s weight compared to other infants that are as tall as the baby (age of the baby is ignored)
- weight-for-length percentile indicates whether the weight at that particular length is appropriate
How do growth percentiles change when malnutrition occurs?
Weight drops first, then length and then head circumference
