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Implications of Artificial Milk Feeding
Dr. Howard TylerAnS 337
Lactation Biology
Introduction to Artificial Milks
Feeding milk or colostrum from one species to newborns of another widely practiced Precocial vs. altricial species concerns Cows milk is primary source
Calves one of most precocial species Creates composition issues
History of Infant Formula Feeding
Formula feeding practiced since WWI Early formulas had no lactose (considered
toxic until ’30’s) Knowledge base of infant nutrient
requirements built on errors in formulation of infant formula
Proteins …
Cow’s Milk-based Formulas
Two main types: 1. Protein diluted to reach amount in
human milk add back CHO, fat, vitamins and minerals
2. Casein diluted to reach amount in human milk
add back lactalbumin, fat, vitamins and minerals
Infant Nutritional Requirements
Related to: Growth velocity
Most rapid rate during lifetime FAR slower than precocial
species Neurological development Vulnerability to dehydration
High surface area:mass Developmental immaturity
Digestive tract Renal function
Developmental Factors Affecting Infant NutritionDigestive tract
Low lipase levels and bile salt concentration Low disaccharidase activity except lactase Low saliva production Low pancreatic amylase activity Small stomach volume (10-20 mL) Low gastric acidity
Renal system Low urine concentrating capacity (700 mOsm/L)
Immune system Intestinal epithelium permeable to macromolecules
Reconciling Developmental Barriers to Infant Feeding
Developmental Factor Addressed by:
pancreatic lipase activity, bile salt concentration
Bile salt-stimulated lipases Medium chain triglycerides
saliva, pancreatic amylases
Simple sugars > Starch
gastric acid Whey > Casein
intestinal permeability Solid food introduced when epithelial closure occurs
urine concentrating capacity
Limit protein, Na+, K+, Cl-,
PO4-2 intakes
Osmolality & Renal Solute Load Human milk: low, less than 300
mosmolar, gut can easily handle Creates renal solute load of 13
mosmol/100kcal Cow’s milk: higher osmolality
Renal solute load of 46 mosmol/100kcal Skim milk with milk solids added: renal
solute load of 86 mosmol/100kcal Infant formulas: 18-25 mosmol/100kcal
Potential Problems Mixing formulas too strong (or weak) Skim milk to infants or children under 2 year
old Energy:protein ratio
Whole milk under 1 year old Allergies
Bacterial contamination Formula, utensils, water all can be sources Length of time between mixing and feeding
Proteins
Whey or soluble proteins form very light curds and are easy to digest Whey proteins in human milk high in IgA These antibodies coat the surface of the small intestine,
blocking binding sites to prevent bacterial attachment and allergens
Casein forms very thick curds and is very difficult to digest
Incidence of colic or pain in abdomen is generally higher in babies fed on cow’s milk because of thick curds that are formed from high amount of casein
Fats
Breast milk contains higher levels of essential fatty acids, linoleic and linolenic acid, which are essential for the development of CNS and eyes
Also contains bile salt-stimulated lipase Fats in breast milk bind less calcium as
compared to other milks
Carbohydrates
Not all the lactose present in breast milk is absorbed
Some gets fermented producing lactic acidThis helps to make the pH of the lower gut acidic Acidic pH inhibits the growth of pathogenic
bacteria thus reducing the chances of diarrheaAcidic pH helps to keep the iron in ferrous form
thus promoting its absorptionGalactose is used during myelinization of the
nervous system
Vitamins
Iron
Calcium
Breast milk contains only about a third of the calcium as compared to cow’s milk Absorption of calcium from breast milk is
much better due to low level of phosphates High levels of lactose also promote
absorption of calcium Less binding of calcium by fats in the
breast milk also helps in promoting better calcium absorption
Advantages of Breast Milk Over Formula Antibodies Less sugar than infant formulas Contains amino acids, fatty acids, cholesterol not
found in formulas Growth factors (epidermal growth factor, etc.) GnRH Delta sleep inducing peptide
Disadvantages of breast milk: harmful substances ingested by mother can pass
to baby (especially lipid-soluble substances)
Anti-infective Properties Bifidus factor: stimulates bifidobacteria, which
fight against pathogenic bacteria IgA, IgM, IgG: immunoglobulins that guard the
gut against infective bacteria Lactoferrin: binds iron away from bacteria Macrophages: phagocytosis of infective
bacteria B12 binding protein: removes B12 from bacteria
Protection Against Infection
Reduces risk and severity of infectious illness among infants
diarrhea otitis media lower respiratory infections bacteremia bacterial meningitis necrotizing enterocolitis infant botulism urinary tract disease sudden infant death syndrome (SIDS) colic
Other Health Benefits for Infant
Enhanced immune response to immunizations Polio Tetanus Diptheria haemophilus influenza
• Promotes cognitive development Better teeth and jaw development• Promotes facial and muscular
development• Promotes normal weight gain• Promotes a strong bond between
baby and mother• Reduces spitting up
Other Breastfeeding Benefits for Baby
Longer-term Health Outcomes
Reduces risk of chronic illness in childhood Some food allergies Type-1 insulin dependent diabetes Lymphoma Asthma Obesity
Health Benefits for the Mother Promotes more rapid return to pre-
pregnancy weight Reduces risk for certain cancers (lower
estrogen) Breast cancer Uterine, ovarian, and endometrial
cancers Reduces post-partum hemorrhage Promotes maternal attachment to baby• Reduces risk of osteoporosis• Saves money (~$1200/year)
Preterm and SGA* Infants: High Nutritional Risk
Physiologically immature Metabolic abnormalities
Fluid and electrolyte imbalances, acidosishypo- or hyperglycemia
Illness present Respiratory distress, sepsis, pneumonia,
meningitis Poor nutrient stores
Fat, glycogen, micronutrients High nutrient requirements
Intravenous (parenteral) feeding often necessary*Small for gestational age
Premature Infants Better growth when fed high-protein formula
Human milk inadequate? Pooled mid-lactation breast milk
Milk from mothers of premature infants differs High protein, high caloric density Low iron, riboflavin, vitamin D, folate
No deficiency symptoms Breast-fed premature infants have higher IQ at age
8 About 8 points on average
Composition of Milk
Excerpts from the American Academy of Pediatrics Policy Statement (Dec. 1997)
Human milk is uniquely superior for infant feeding Human milk is the preferred feeding for all infants,
including premature and sick newborns When direct breastfeeding is not possible,
expressed human milk, fortified when necessary for the premature infant, should be provided
Exclusive breastfeeding for approximately 6 months Continuation of breastfeeding for at least 12
months and thereafter for as long as mutually desired (WHO says 2 yrs. of age or beyond)
http://www.aap.org/policy/re9729.html
Milk Consumption by Adult Humans
Proteins have high biological value, although can be allergenic
Lactose intolerance primary problem Passes into large intestine
Cramps, bloating, diarrhea Most commonly develops between ages 1 and 4
Ethnic differences 10% white European descent, 70% in blacks Also high in people of Mediterranean descent
Lactase levels both constitutive and induced Some dietary manipulation possible
Neonatal Reflexes in Breast Feeding
Sucking or Suckling? Sucking – application of negative
pressure Like when you drink through a straw
Suckling involves a co-ordinated use of the tongue, lips and gums Premature infants often lack
coordination to suckle
Suckling
Nipple, areola, & underlying breast tissue are drawn into the infant’s mouth
Lips & cheeks form a seal, with the lips flanged outward
Nipple elongates to 2-3 times its resting length into a teat by suction
Jaw moves the tongue up, compressing the areola against the alveolar ridge, causing expression from the milk sinuses
The tongue then moves in a peristaltic motion, channeling milk to the pharynx for swallowing
Jaw lowers, filling the milk sinuses again
Teat
Tongue
Palate
Problems During Suckling
Low suction Inconsistent, irregular suckling bursts Poor endurance
Patent ductus arteriosus
Nipple Confusion
Action of sucking from the bottle is very different from suckling at the breastIn bottle feeding, the baby sucks at the nipple
and uses his tongue to stop the flow of milkIn breast feeding, the baby uses the tongue to
express milk from the breastBabies who have been bottle-fed try to suck
at the mother’s nipple rather than suckle - often called nipple confusion
Comparison of Breastfeeding with Bottle-feeding (Oral Skills)
In bottlefeeding:
Mouth less open, lips don’t need to be everted Bottle doesn’t have to be far back in the mouth Protective tongue action of anterior-superior
tongue movement to stop fluid flow Difficult to rest at the bottle – milk keeps
flowing
Breast feeding Bottle feeding
Tongue used to express milk Tongue used to stop milk
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