Transcript Neonatal Growth and Nutrition

Pediatric Nutrition I

Nutrition of Neonates and Infants
– Prior to 1 year of age
– Growth Rates and Nutritional Goals
– Nutrient Requirements


Energy, Protein, Minerals, Vitamins
Absorptive/Digestive Immaturity
– Human Milk
– Infant Formulas

Growth rates are most rapid in the first six
months of human life

Nutrient requirements on a weight basis are
highest during the first six months

Rapid organ growth and development occurs
during the last trimester and first six months

The detrimental effects of nutritional
insufficiencies are magnified during periods of
rapid organ growth (I.e., vulnerable periods for
brain growth)


Provide sufficient macro- and micronutrient
delivery to promote normal growth rate and body
composition, as assessed by curves which are
generated from the population
Curves exist for:
– Standard anthropometrics: weight, length, OFC
– Special anthropometrics: arm circumference, skinfold
thickness
– Body proportionality: weight/length, mid-arm
circumference: head circumference ratio

Body composition measurements (e.g. DEXA,
PeaPod) are not standardized yet
GIRLS
Birth to 36 mo
BOYS
Birth to 36 mo
 Term
infants require 85-90 Kcal/kg/d if
breast-fed, 100-105 Kcal//kg/d if
formula
 Differences
are due to increased
digestibility and absorbability of
breast milk
– Presence of compensatory enzymes
(lipases)
(Continued)
 Energy
requirements are 20% higher
in premature infants due to:
– Higher basal metabolic rate
– Lower coefficient of absorption for fat
and carbohydrates
 Energy
requirements decrease to 75
Kcal/kg/d between 5-12 months
Basal Metabolism
Gross
Metabolizable
Energy
Energy
Intake
Intake
Thermic Effect of Feeding
Activity
Energy Stored “growth”
Tissue Synthesis
Energy Excretion

Diseases of infancy that increase BMR
(cardiac, neurologic, respiratory) affect
energy requirements

Diseases that increase nutrient losses
(malabsorption due to cystic fibrosis,
celiac disease, short bowel syndrome)
increase the need for energy delivery,
although the BMR is normal

Late gestation and infancy is the time of
highest protein accretion in human life

Protein requirements range from 1.5 g/kg/d
(healthy breast-fed infant) to 3.5 g/kg/d
(septic, preterm infant)

Amino acid synthesis is incomplete in the
premature; taurine and cysteine are
additional essential amino acids because of
immaturity of enzyme systems
 Preterm
infants:
15 g/kg/d
 Toddlers:
6 g/kg/d
 Adolescents:
4 g/kg/d
Nutrient
Term
Preterm
5-12 Month
Neonate
Neonate
Infant
Na (mEq/kg/d)
2-3
4-7
1-2
K
1-2
2-4
1-2
Ca (mEq/kg/d)
60
150
40
Iron (mEq/kg/d)
1
2-4
0.7
0.4
0.3
(mEq/kg/d)
Zinc (mEq/kg/d)
0.2 - 0.5

Water-soluble vitamins (B, C, folate, etc.)
are rarely a problem in newborns and
infants; babies are born with adequate
stores and/or all food sources have
adequate amounts

Fat-soluble vitamins (A,E,D,K) may present
significant problems because of relatively
poor fat absorption by newborn infants
(especially premature infants)


K: Needs to be given at birth to prevent
hemorrhagic disease of newborn; adequate
thereafter due to synthesis by intestinal
bacteria
D: Low amounts in breast milk; infants
born in winter in north and infants who are
clothed at all times (minimal sun exposure)
have been identified with rickets
 AAP now recommends 400 IU/d for all infants
(Continued)

A: Essential for normal structural collagen
synthesis and retinal development
deficiency in premature infants contribute
to fibrotic chronic lung disease

E: Antioxidant that protects against
peroxidation of lipid membranes; preterms
have poor antioxidant defense and are
subjected to large amounts of oxidant
stress; vitamin E deficiency causes severe
hemolytic anemia
Rapid transit time
+
Immature digestive capabilities
=
Reduced nutrient retention

Primary sources of CHO in newborn
and infant diet are disaccharides (esp.
lactose)

Disaccharides must be broken into
component monosaccharides to be
absorbed
– Lactose = glucose + galactose (lactase)
– Sucrose = glucose + fructose (sucrase)
– Maltose = glucose + glucose (maltase)
 Intestinal
lactase concentrations are
low at birth and are not inducible
 Amylase,
necessary for breaking
down starches, are not adequate
until > 4 months
Sucrase, Maltase, Isomaltase
Glucose Uptake
Salivary Amylase
Zymogen Granules in Pancreas
Pancreatic Amylase
Lactose
Gluco-amylase
10 Wks
20 Wks
22 Wks
24 Wks
24 - 28 Wks

85 % of ingested protein is absorbed in
spite of functional immaturities:
– Reduces stomach acidity
– Low pancreatic peptides levels
(chymotrypsin caroboxypeptidases)

Compensation is by trypsin and brush
border peptidases
 Adult:
 Term
95%
infant: 85-95%
 Preterm
infant: 50 - 90%
(dependent on source of fat)
 Low
levels of intestinal lipases
 Small
bile salt pool
 Committee
on Nutrition of the AAP
strongly recommends breastfeeding
for infants
 The
rates of breastfeeding have risen
recently, but the attrition rate is high
(Continued)

The goal of the AAP and NIH Health People
2010 is to have 75% women breastfeed, with a
continuation rate of 50% at 6 months

It is necessary to breastfeed for at least 12
weeks to achieve the immunologic and
disease preventative benefits of breast milk

Physician’s role is to support, counsel and
trouble-shoot
 Health
 Nutritional
 Immunologic
 Neurodevelopmental
 Economic
 Environmental
 Studies
in developed countries
– Reduced prevalence of:
Diarrhea
» Otitis media
» Lower respiratory infection
» UTI
» NEC (in preterms)
» SIDS
»
 Protection
of infant from chronic
diseases:
– Insulin dependent diabetes mellitus

(OR 0.61)
– Inflammatory bowel disease
– Allergic disease
– Childhood lymphoma (OR 0.91)
– Obesity (OR 0.75-0.87)
 Protection
of mother from:
– Pregnancy
– Postpartum hemorrhage
– Bone demineralization
– Ovarian cancer

Complete human nutrition for 6 months
– Iron at 4 months
– Vitamin D in northern climates, covered
infants and mothers, vegetarians (vegans)

Energy is more accessible than from
formula
– Compensatory lipases  better fat
retention
– But, BF babies grow slower too
 Amino
acid spectrum matches
infant need; lower protein and
solute load
 Faster
reflux
gastric emptying  less
 Better
visual acuity (early)
— Role of DHA?
 Higher
IQ (debatable)
— Independent of nursing
— Components in human milk which
may potentiate the effect:
»
»
DHA
Growth factors
 25%
reduced risk of obesity if BF
— Adjusted OR: 0.75-0.89
—Dose response (Koletzko et al)
—
Rate of Adolescent Obesity
—12% if BF < 1month
—2% if BF 12 months
—“Small” effect compared to OR if
parents are obese (4.2), low physical
activity (3.5) or TV (1.5)

Reduced cost of feeding
— No formula cost (-$855/year)
— Increased maternal consumption (<+$400)
— Net savings of >$400/child

Reduced health care costs due to:
— Lower incidence of childhood illness

Reduced income loss due to:
— Less days lost to cover childhood illness



Galactosemia in infant
Illicit drug use by mother
Certain maternal infectious diseases
— Active TB
— HIV (US only)
— Not CMV

Certain maternal medications
— Anti-neoplastics, isotopes, etc
— How about SSRI's?

Promotes adequate growth, but not brain and
immunologic development compared to human
milk
 New formulas contain LC-PUFAs
 Soon to be added: prebiotics; probiotics

Most are cow-milk based, although soy-protein
based and fully elemental formulas are
available
(Continued)

Cow’s milk (not formula) is contraindicated in
the first year of life
— High solute load can lead to azotemia
— Inadequate vitamin D and A
— Milk fat poorly tolerated
— Low in calcium; can lead to neonatal seizures
— Gastrointestinal blood loss/sensitization to cowmilk protein

Feed humans human milk
— It is species specific

If not human milk, CMF or Soy formulas
with iron are indicated

Hypoallergenic formulas are highly
specialized, expensive and overused