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

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Growth rates are most rapid in the first six months of human life

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Nutrient requirements on a weight basis are highest during the first six months

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Rapid organ growth and development occurs during the last trimester and first six months

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The detrimental effects of nutritional insufficiencies are magnified during periods of rapid organ growth (I.e., vulnerable periods for brain growth)

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Provide sufficient macro- and micronutrient delivery to promote normal growth rate and body composition, as assessed by curves which are generated from the population

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Curves exist for:

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Standard anthropometrics: weight, length, OFC Special anthropometrics: arm circumference, skinfold thickness

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Body proportionality: weight/length, mid-arm circumference: head circumference ratio

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Body composition measurements (e.g. DEXA, PeaPod) are not standardized yet

GIRLS Birth to 36 mo

BOYS Birth to 36 mo

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Term infants require 85-90 Kcal/kg/d if breast-fed, 100-105 Kcal//kg/d if formula

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Differences are due to increased digestibility and absorbability of breast milk

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Presence of compensatory enzymes (lipases)

(Continued) 

Energy requirements are 20% higher in premature infants due to:

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Higher basal metabolic rate

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Lower coefficient of absorption for fat and carbohydrates

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Energy requirements decrease to 75 Kcal/kg/d between 5-12 months

Gross Energy Intake Basal Metabolism Metabolizable Energy Intake Thermic Effect of Feeding Activity Energy Stored “growth” Tissue Synthesis Energy Excretion

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Diseases of infancy that increase BMR (cardiac, neurologic, respiratory) affect energy requirements

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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

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Late gestation and infancy is the time of highest protein accretion in human life

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Protein requirements range from 1.5 g/kg/d (healthy breast-fed infant) to 3.5 g/kg/d (septic, preterm infant)

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Amino acid synthesis is incomplete in the premature; taurine and cysteine are additional essential amino acids because of immaturity of enzyme systems

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Preterm infants: 15 g/kg/d

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Toddlers: Adolescents: 6 g/kg/d 4 g/kg/d

Nutrient Term Preterm 5-12 Month Neonate Neonate Infant Na (mEq/kg/d) K (mEq/kg/d) Ca (mEq/kg/d) 2 - 3 1 - 2 4 - 7 1 - 2 2 - 4 1 - 2 60 150 40 Iron (mEq/kg/d) 1 2 - 4 0.7

Zinc (mEq/kg/d) 0.2 - 0.5 0.4 0.3

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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

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Fat-soluble vitamins (A,E,D,K) may present significant problems because of relatively poor fat absorption by newborn infants (especially premature infants)

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K: Needs to be given at birth to prevent hemorrhagic disease of newborn; adequate thereafter due to synthesis by intestinal bacteria

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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

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AAP now recommends 400 IU/d for all infants

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A: Essential for normal structural collagen synthesis and retinal development deficiency in premature infants contribute to fibrotic chronic lung disease

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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

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Primary sources of CHO in newborn and infant diet are disaccharides (esp. lactose)

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Disaccharides must be broken into component monosaccharides to be absorbed

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Lactose = glucose + galactose (lactase)

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Sucrose = glucose + fructose (sucrase)

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Maltose = glucose + glucose (maltase)

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Intestinal lactase concentrations are low at birth and are not inducible

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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 10 Wks Lactose 20 Wks 22 Wks 24 Wks Gluco-amylase 24 - 28 Wks

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85 % of ingested protein is absorbed in spite of functional immaturities:

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Reduces stomach acidity

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Low pancreatic peptides levels (chymotrypsin caroboxypeptidases)

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Compensation is by trypsin and brush border peptidases

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Adult: 95%

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Term infant: 85-95%

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Preterm infant: 50 - 90% (dependent on source of fat)

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Low levels of intestinal lipases

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Small bile salt pool

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Committee on Nutrition of the AAP strongly recommends breastfeeding for infants

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The rates of breastfeeding have risen recently, but the attrition rate is high

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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

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It is necessary to breastfeed for at least 12 weeks to achieve the immunologic and disease preventative benefits of breast milk

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Physician’s role is to support, counsel and trouble-shoot

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Health

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Nutritional

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Immunologic

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Neurodevelopmental

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Economic

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Environmental

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Studies in developed countries

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Reduced prevalence of:

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Diarrhea

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Otitis media

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Lower respiratory infection

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UTI

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NEC (in preterms)

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SIDS

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Protection of infant from chronic diseases:

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Insulin dependent diabetes mellitus

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(OR 0.61)

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Inflammatory bowel disease

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Allergic disease

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Childhood lymphoma (OR 0.91)

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Obesity (OR 0.75-0.87)

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Protection of mother from:

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Pregnancy

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Postpartum hemorrhage

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Bone demineralization

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Ovarian cancer

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Complete human nutrition for 6 months

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Iron at 4 months

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Vitamin D in northern climates, covered infants and mothers, vegetarians (vegans)

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Energy is more accessible than from formula

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Compensatory lipases

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retention better fat But, BF babies grow slower too

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Amino acid spectrum matches infant need; lower protein and solute load

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Faster gastric emptying

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reflux less

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Better visual acuity (early)

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Role of DHA?

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Higher IQ (debatable)

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Independent of nursing

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Components in human milk which may potentiate the effect:

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DHA

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Growth factors

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25% reduced risk of obesity if BF

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Adjusted OR: 0.75-0.89

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Dose response (Koletzko et al)

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Rate of Adolescent Obesity

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12% if BF < 1month

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2% if BF 12 months

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“Small” effect compared to OR if parents are obese (4.2), low physical activity (3.5) or TV (1.5)

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Reduced cost of feeding

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No formula cost (-$855/year)

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Increased maternal consumption (<+$400)

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Net savings of >$400/child

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Reduced health care costs due to:

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Lower incidence of childhood illness

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Reduced income loss due to:

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Less days lost to cover childhood illness

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Galactosemia in infant

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Illicit drug use by mother

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Certain maternal infectious diseases

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Active TB

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HIV (US only)

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Not CMV

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Certain maternal medications

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Anti-neoplastics, isotopes, etc

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How about SSRI's?

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Promotes adequate growth, but not brain and immunologic development compared to human milk

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New formulas contain LC-PUFAs

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Soon to be added: prebiotics; probiotics

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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

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High solute load can lead to azotemia

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Inadequate vitamin D and A

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Milk fat poorly tolerated

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Low in calcium; can lead to neonatal seizures

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Gastrointestinal blood loss/sensitization to cow milk protein

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Feed humans human milk

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It is species specific

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If not human milk, CMF or Soy formulas with iron are indicated

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Hypoallergenic formulas are highly specialized, expensive and overused