1

NUTR 3340Life Cycle Nutrition

Lactation

Breast Anatomy and DevelopmentAnatomy of mammary gland

1) mammary gland contains milk producing cells and a duct system2) Nipple surrounded by a pigmented area called areola3) Alveoli - gland cells that produce the milk4) Milk passes from the cell to the ductule into the lactiferous duct sinus through the nipple

Breast development1) immature ducts and glandular lobules present at birth2) growth at puberty

Breast maturation1) progesterone promotes lobular development2) most women that want to breast feed can; insufficient mammary tissue only in rare cases such as post surgical etc3) pregnancy is needed for satisfactory milk production4) placental hormones promote mammary growth

Physiology of lactationGeneral activity

1) Initial postpartum secretions on day 2 or 3 is colostrum. By one week lactation is established although it may take up to three weeks2) milk production

a) synthesisb) secretionc) propulsion or ejection of milk along a duct system

3) most of the synthesis of the milk is during suckling

Fat synthesis and release1) Fatty acid synthesis and triglyceride formation is in the endoplasmic reticulum2) milk secretions enter ductules by apocrine secretions

Protein synthesis and discharge1) most milk proteins are specific to mammary secretions2) main proteins are casein, alpha and beta-lactalbumin

3) synthesis is in the rough endoplasmic reticulum4) released into a ductule from the Golgi apparatus by apocrine secretion or reverse pinocytosis

2

CHO synthesis and release1) Lactose is the predominant CHO2) release by reverse pinocytosis

The role of Hormones1) prolactin is the stimulus for milk production2) maintenance of milk secretions is from anterior pituitary hormonal factors stimulated by sucking3) oral contraceptive agents (only estrogen) inhibit milk production

Let down reflex1) sucking stimulates release of oxytocin from the posterior pituitary2) oxytocin causes milk ejection3) psychological factors can influence;

a) stress or embarrassment may inhibitb) set off by thought or sound of baby crying

4) successful let down - dripping of milk before the feeding Sucking is needed to maintain lactation - feeding on demand is desired Duration of lactation depends on local and cultural patterns. After 12 months of age the quantity of milk decreases usually due to reduced demand.

The Nature of Mammalian MilkThere are unique species variations - changes particularly in concentration and fat content

Human milk is dilute and low in fat most similar to marsupials and animals that hibernate. The mothers are readily available and the young nurse frequently.

Nature of Human Milk1) Basic contents - basically a solution of protein, sugar, salts and fatty compounds. More than 100 components have been recognized.

There is variation in human milk largely due to maternal intake except for some of the vitamins and fat.

In famines the quality of the milk usually remains good but the quantity decreases.

Composition of human milk;varies from one human to anotherone period of lactation compared to anothertiming of the withdrawalgestational agematernal;

ageparityhealthSES

3

2) Milk volume The volume of milk is variable but the average is 600-900ml/day If there is severe food restriction the volume of milk decreases

Colostrum is the first fluid It is an opaque liquid on days 1-3, about 2-10 ml/feeding The color is yellow due to carotene It is high in protein and low in sugar and fat Fewer calories than mature milk

Transitional milk Colostrum changes to transitional milk by day 3 to 6. After 10-13 days the major changes are finished. At this time the protein may be

somewhat high but it falls gradually to a stable level by 4 weeks with a corresponding rise in fat and CHO.

Composition of Mature Mother's MilkProtein 1) It is about 0.8-0.9 g/100ml

(Colostrum 2% and Transitional milk 1.5%) Much lower protein in human compared to cow milk

2) The major types of protein are casein and whey (eg. lactalbumin and lactoferrin)3) Low maternal intake does not affect milk quality - maternal reserves are used.

Severe protein deficiency can lead to reduced protein in the milk4) amino acid content is perfect for human babies

Some amino acids are lower than cow milk;phenylalanine, tyrosine and methionine.

The enzyme systems to metabolize phe, tyr and met are immature so reduced amounts of these amino acids may spare harmful affects to the brain

human milk contains increased cystine which the baby may not be able to adequately synthesize

Taurine is higher in human than cow milk. Taurine content is high in fetal brain therefore may be important. Needed for bile acid conjugation and may be needed for the retina.

Non-protein nitrogen25% of nitrogen is non-protein;

peptides free amino acids urea creatinine sugaramines

4

Lipids1) Amount of fat in human milk:

varies from one woman to anothervaries by parityvaries by season

Average is 2.02 - 5.3%foremilk lower in fatlast milk higher in fat (3X greater than foremilk)

2) Types: a) triglycerides make up 90% of the fatb) Others include;

phospholipidscholesterolmono and diglyceridesglycolipidssterol estersFFA's

Comparison of human and cow milk; linoleic acid (essential fa) is higher in human than cow milk short chain fa's (C4-C8) lower in human than cow cholesterol is higher in human than cow milk; speculated;

- needed for myelin synthesis- stimulates development of the enzymes for degradation of cholesterol

Eicosapentanoic acid (EPA) and docosahexanoic acid (DHA) are present in human milk and not in cow milk. They may be essential for the brain and retina.

3) The fat content varies considerably with the maternal diet Diet high in PUFA makes milk high in PUFA If energy is severely restricted fat is obtained from maternal stores If diet is high in CHO there are increased fatty acids with carbon chains less than C16.

Mechanism and reason unclear.

4) Lipases in milk lipoprotein lipase and others in the milk lead to lipolysis if left refrigerated or frozen Other lipases are only activated when they encounter bile; this occurs in the intestine and

may lead to improved triglyceride hydrolysis and improved fat digestion by breast fed babies.

5) Carnitine - facilitates the transport of LCFA's across the mitochondrial membrane. Source is diet and synthesis from lysine and methionine. In infants there may be a limited capacity to synthesize Human and cow milk have similar quantities.

5

Carbohydrates1) Lactose (glucose and galactose)

In human milk 7% in cow milk 4.8 % content in the milk not affected by maternal diet Advantages of lactose in the milk;

a) slowly digestedb) stimulates growth of microorganisms in the gut that synthesize vitamins and produce organic acids (acidic pH) which prevent growth of undesirable bacteriac) improves mineral absorption

2) Other CHO's are present in small amounts3) amylase - starch splitting enzyme present in early infancy (pancreatic amylase low or absent)

Minerals Most striking difference between human and cow

Cow milk has compared to human milk;phosphorus 6 times highercalcium 4 times higherAsh 3 times higherprotein 3 times higher

This leads to increased waste for the kidney. Kidneys in newborns are immature and the waste from breast milk is suited.

Major minerals in human milk - K, Ca, P, Cl, Na trace amounts of minerals in human milk - Fe, Cu, Manganese

total content is fairly constant; some minerals may change with the course of lactationo little relationship between maternal intake and content in milk

Bioavailability of iron and zinc in breast milk better than cow milko nonsupplemented women that breast feed the infant may have negative iron

balance between 3 and 6 months

Fat Soluble Vitamins All vitamins necessary are supplied in human milk The major factor influencing their content in human milk is maternal intake mothers intake low - level in infant low mother's intake improves - infants level improves mother's intake super high - infants level plateaus does not keep going up

Vitamin D low in human milk .5-1.5 ug/L sunshine and diet intake can affect the level in the infant unclear if supplement is needed - if mother's intake is low and no chance of getting from

sun, supplement may be good idea

6

Vitamin A Adequate in human milk Affected by the quantity and quality of mother's intake Seasonal variation not so pronounced due to extended growing season, supermarket and

frozen foods

Vitamin E is greater in human than cow milk

Vitamin K 2 ug/L in mature human milk; 60 ug/L in cow milk infant is born with sterile intestinal flora; it takes several days for the microbe population

to be established hemorrhagic disease has been reported as long as 4 weeks after delivery in breast fed

babies due to low vitamin K. All babies are given vitamin K supplement at birth

Water soluble vitamins reflect the maternal diet and supplements taken vitamin C - mother taking 90, 250 or 1000 mg/day same content in human milk B12 - from well fed mothers no problem strict vegetarian women deficiency is a problem

Resistance factors bifidus factor - Nitrogen containing polysaccharide that favors growth of lactobacillus

o bifidus protects against enteropathic organisms Immunoglobulins

o IgA, IgD, IgE manufactured in mammary tissueo IgG - lymphoblasts migrate from the maternal serum to the mammary gland -

antigenic exposure from distance sites - antibody synthesis occurs in mammary gland - protects the infant

o IgA - secretory immunoglobulin predominant in human milk. Especially high in colostrum. Major host resistance factor against organisms that infect the GI tract like E-Coli and enterovirus.

Other host resistance factors Lysozyme - antibacterial enzyme human milk 300 times greater than cow milk Lactoferrin - prevents candida albicans - inhibits growth of staph and E-coli by binding

iron which the bacteria require Lactoperoxidase - combats strep prostaglandins - may protect the GI tract Lymphocyte - macrophage activity

o lymphocytes in human milk produce interferon (antiviral substance)o macrophages - produce complement, lactoferrin, lysozyme and others

7

Preterm milkPreterm milk refers to the milk produced by a mother who delivered her baby earlier than the expected timePreterm milk is higher in several nutrients compared to term milk;

proteinnonprotein nitrogencalciumIgAsodiumpotassiumchloridephosphorusmagnesiumMCFA, PUFA, total lipids

Preterm milk is lower in lactose Preterm infants grow better is fed their own mother's milk rather than banked breast milk Commercial formulas geared for LBW led to better growth than banked human milk In spite of the increased nutrients in preterm milk the protein and sodium are marginal

and the calcium and phosphorus are too low for the preterms needs. A fortifier should be added to the milk to increase protein, CHO, calories and Calcium

and phosphorus

Maternal malnutrition In severely malnourished women;

IgG 1/3 normal concentrationAlbumin 1/2 normalIgA is lowC4 (a component of complement) is low

ContaminantsDrugs In general 1-2 % of maternal dose goes to the infant Specific drugs;

sedatives should not be taken - infant drowsy; won't eatlithium carbonate for maniac depression - reduced body temperature, poor muscle tone and bluish skincyclophosphamides and methotrexate - bone marrow depressionpenicillin - may induce allergy in infantradioactive thyroid - may damage thyroid of infantsome laxatives may cause bowel problems in infantheroin - dependency in infant

8

methadone treatment - may lead to infant death

If a drug is believed to be safe and is used; use short acting - easier for the babies liver to detoxify and excrete take immediately after breast feeding so that smallest amount will appear in milk watch the baby for any signs of reaction use the smallest dose possible

Environmental contaminants Organohalides - accumulate in fat of breast milk

PCB'sDDT There is no amount that is known to be safe; try to avoid

Heavy metalso lead and mercury are transferred to the fetus by the placenta and baby by the milk

Nicotine - "poisoning"mother's who smoked 6-16 cigarettes per day infants refused to suckle, become apathetic, vomit and retain urine and feces. Caffeine - 1% transferred but can accumulate over time

o 6-8 cups baby can get the nervous jitters alcohol - Similar amount in baby as in the mother's blood

o Increased alcohol intake Cushingoid appearanceo Cushing's syndrome increased secretion of ACTH or intake of corticosteroids that

cause rapid development of fat deposits around the face , neck and trunk giving a "moon face" appearance.

o Several drinks a day can lead to an infant with developmental delay AIDS virus - The aids virus can be transmitted through human milk In this country it is good to discourage breast feeding if mother is HIV positive Breast milk banks screen donors and pasteurize the milk to destroy the virus

Diet for the Nursing MotherGeneral recommendations

The RDA is greater than non-pregnant women requirements are based on the amount of milk produced

Energy 2-4 kg of body fat are stored during the pregnancy that will provide 200-300 kcal/day for

lactation for the first three months estimated additional calorie needs for lactation RDA+500 kcalories successful lactation can occur with a gradual weight loss with energy intakes less than

recommended RDA 2200 calories, plus 500 for lactation, minus 300 provided by fat stores, minus 500

calories for weight loss = 1900 calories needed for lactation moderate to severe energy restriction will compromise the ability to synthesize the milk

9

Encourage gradual weight loss over the first 6 months or milk supply may become inadequate

Protein RDA 71 gms (non-pregnant 46 gms)

Vegetarian diets appropriate sources for the extra calories and protein are needed Kale and calcium fortified food if no dairy; mixing proteins with limiting amino acids to

get better utilizations of the protein If they eat dairy products no problem Diet supplements if acceptable

Supplements Probably not needed if woman has healthy diet however, often recommended that

woman continues the pre-natal vitamin Increased needs are met by the increased foods calcium supplement if no milk to prevent bone depletion

Cost of lactation Variable depending on the cost of the items chosen to add the calories If economical choices are made it can be cheaper than commercial feeding

Advantages of Breast Feeding Human milk was designed for humans Lactation is a normal process for mammals

Anti-infective Properties At the turn of the century there was not much knowledge about microbiology or

immunology. Bottle fed babies had a much higher problem with diarrhea and acute GI infections leading to increased mortality

Today in this country there is only a small increased mortality in bottle fed babies There is decreased morbidity in breast fed babies which could be due to the anti-infective

properties or other factors

Optimum Nutrition Breast feeding avoids problems such as improper dilution of the formula (The calories

and protein in breast milk are ideal for growth) over diluted - growth failure under diluted - excess growth and increased renal solute load Colostrum and mature breast milk contain many factors and micronutrients whose

functions are unclear

10

Appropriate Growth and Development Breast fed and bottle fed babies follow the same growth pattern for the first 3 to 4

months Then bottle fed babies gain weight faster The slower rate of weight gain of the breast fed baby is probably the ideal pattern There are not standard growth charts for bottle versus breast fed babies

Reduced Risk of Allergy Food allergy is associated with penetration of intact proteins or large peptides with

antigenic determinants across the mucosal barrier Usually a mucosal barrier is formed in the intestine of the infant by secretory antibody

by;o efficient intraluminal digestiono impermeable intestinal epithelial cellso impermeable intracellular junction

The maximum time for whole macromolecule absorption is in the newborn period and decreases with age

There is increased allergy in formula fed infants. Exact mechanism is unknown but breast fed infants may;

o promote early closure of mucosal barriero antibodies toward milk components have been found in breast milko These may hinder intestinal absorption of intact immunogenic foods and decrease

allergies Allergy to breast milk probably does not exist.

o However, a mother can pass an allergen from a food she has eaten through the breast milk to the infant promoting an allergic reaction.

o It takes 4-6 hours for the food she has eaten to appear in the milk; eliminate the offending food.

Normal psychological development Breast feeding induces maternal-infant bonding Prolactin may produce mothering responses there is a special closeness between breast fed children and their mother's

Reduced risk of obesity - this has not been supported by data so far

Other benefits In LBW (low birth weight) may prevent NEC (necrotizing enterocolitis) and may prevent

other diseases

Maternal Benefits Oxytocin - promoted involution of the uterus (shrinking back to it's normal size) Suppression of ovulation - short term spacing of children in under developed countries

attributed to this. The effect is lost as the demand for solid food increases.

11

Ease of feeding - early there may be more time spent in breast feeding until the supply meets the demand. After this time bottle feeding takes more time if you include preparation and clean up.

Breast milk - costs less and is more economical

Incidence of Breast FeedingUnited States

In 1950-1960's - 82% of infants were bottle fed This trend started to reverse in the 1970's and peaked in about 1980 with about 60% of

babies breast fed In 1998 breast feeding rate 64% in early post-partum period, declines to 29% at 6

months. The 1998 breast feeding rate is similar for whites (68%) and Hispanic (66%) women.

Rates are lower in younger, and unmarried, and low income women.

Current trends preterm infants are being fed breast milk employment

In Baltimore area; Planning to return to work in the first 6 months did not affect decision to breast feed Over 50% who returned to work stopped breast feeding as early at 2-3 months 2/3 of the women who did not return to work early continued breast feeding part-time employment (20 hrs/wk) continued breast feeding

Regional differences higher in Mountain and Pacific regions and lowest in East South Central

Breast feeding is recommended by the American Academy of Pediatrics, promoted by Pediatricians, WIC workers and other health care professionals

Prenatal and postpartum careDecision to breast feed

Health care professionals should present the advantages to breast feeding and support breast feedings early. After parents make their decision, support their decision.

Instructions on how to breast feed are desirable while in the second trimester. The Father should be included, if possible.

Advantages of breast feedingrespond to questions and concernsphysiology and anatomyDiet needs

mother's diet, rest If a certain food is suspected of causing gas eliminate it from the mothers diet Adequate rest, diet and fluids are essential; there is a growth spurt between 6-12 weeks;

12

stress reduces quantity therefore rest etc important Other anxieties;

o Growth failure is only evidence that lactation is inadequate;o Studies indicate growth will fall between 6-15 months if only breast milk is given

(need solid foods as well)

Effect of anesthetics Some anesthetics can make the baby lethargic and disinterested in feeding - May take an

extra day of two to establish lactation.

Feeding Start each feeding on alternate breast Feeding 7-10 minutes on each side

Typical Concerns Concern over quantity and quality of milk Sufficient quantity of milk milk produced is equal to demand - may take a day or two for the supply to reach the

demand the let-down-reflex can be influenced by stress - best support is positive support monitoring growth is the best way to know if quantity is adequate

infant should gain 1/3-1/2 pound per week

In-Hospital Postpartum support Make the mother feel at ease Include the father as he can give support later

Positions be sure the baby is able to breath and swallow properly lying down, sitting or football hold

Baby's response not every cry is from hunger - there should be at least 6 wet diapers per day sometimes need to be burped, change diapers, gas or want to be held

milk quality quality of milk overall is stable shouldn't feel guilty if baby is fussy or has gas

Resources for breast feedingHealth professionalsReferences

13

Talk to other mothersLa Leche League

NipplesNursing bra can be worn day and night.Leave breast exposed to air for about 10 minutes after feeding to let them dryNo ointments or lotion they may remove natural lubricants and may not be good for the babySoap is drying wash only with waterinverted nipples may need a shield or a pump

Nipple Soreness Soreness for a few seconds is normal due to stimulation of the breast by oxytocin during

let down Tenderness and redness usually from tissue breakdown - best is to try to prevent

problems but treat quickly when problems occur to prevent further problems Insert finger to remove suction when removing infant from the breast

Treatment:1) Check for proper position of baby2) feed on demand - if too hungry may suck too hard leading to soreness3) vary the feeding position4) begin feeding on breast that is least tender - switch in middle to tender breast - and end feeding on least tender breast5) terminate feeding when complete; usually 7-10 minutes per side6) Air dry breast for at least 10 minutes 7) Avoid soaps, alcohol or petroleum based compounds - use only lanolin or breast creams if recommended by doctor. Some women apply cooled tea bags 2-3 times per day tannic acid in the tea has a healing effect.

Engorgement The breasts feel hot, heavy and hard with milk. Normally occurs on first day of full milk production. Probably caused by a combination of increased mammary tissue, edema and the newly

produced milk It can cause mild to severe discomfort for the mother If not taken care of promptly can lead to stress for the mother and a hungry frustrated

baby

Treatment:1) feed at least every three hours, be sure baby has proper grasp2) If supply is greater than demand limit feeding to 5 minutes per side and pump to relieve the pressure or pump before if needed for baby to get proper grasp3) moist heat or warm shower helps and massage while feeding to help drain the ducts

Leaking

14

This is a normal experience often occurring early in lactation. It is a sign of normal milk production and let-down reflex

Supplemental feedings - Lactation is usually well established after 4 weeks At this time a bottle can be offered once or twice a week Feeding can be given by father or other family member Bottle should provide feeding as close to breast feeding as possible and burp more often

as they will swallow more air Powdered formula is the most economical for the supplement As the infant gets older it is possible to replace one feeding with a bottle and breast feed

at other feedings

Expression of milk Manual for small amounts Pumps

o Manual pumps usually create increased negative pressure and don't work well. They can cause pain and even damage

o Electric pumps can be rented when the mother needs to express the milk for a few days or weeks (preterm, mother who works)

Storage of milk Fresh milk is safe for up to 6 hours after expression, refrigerate 1-2 days. Freezing prevents microorganism growth with minimal changes in the composition

o Freezing causes some of the membranes of the milk cells to break leading to lipolysis

o Other components eg. nutrients, immunoglobulins and antibodies are unchanged Heat treatment can reduce the protective factors

Duration In many parts of the world 2-3 years for lactation is common The most common termination is one year of age - often happens spontaneously At this time the infant should be receiving adequate supplementary foods, they breast

feed less often and are more curious May be a feeling of relief or rejection for mother - may need support

Special problems:Contraindications

a) Galactosemia - inherited genetic disease baby cannot breakdown lactose, requires a lactose-free formulab) PKU - need a low phenylalanine formula, can partially breast feed along with a medical food low or free of phenylalaninec) HIV positive or Women with AIDS should not breast feed

15

d) alcoholics or substance abusers should not breast feed even marijuana inhibits prolactine) chronic disease - TB if active can pass in milk or if on drugs for treatment of disease

2) Cesarean birth - Effects of the anesthetic wear off quickly Should not contraindicate breast feeding - if in pain should take medicine 15-30 minutes

before the feeding

3) Poor let-down emotional stress and anxiety release adrenalin which suppresses oxytocin - encourage

activities that relax4) Breast feeding should be continues for the following;

colds and influenza - the baby has already been exposed by the time the mother comes down with the symptoms; symptoms in baby mild if any

clogged milk ducts can be caused by incomplete emptying or not varying the feeding position

feed more frequentlymoist heat and massagevary the positions and increase the feeding time

Once the plug is removed dramatic improvement mastitis similar to engorgement except can be fever

bed restantibioticscontinued feedings ( increased stasis will make problem worse)

abscess - localized pus and swelling discontinue breast feeding on affected sidepump milkantibioticsmassage or possibly surgical drainage

Maternal DiseaseIf woman with chronic disease can successfully complete pregnancy often can breast feed

1) Diabetes - watch for infections2) thyroid - hyperthyroid take drugs to inhibit synthesis of thyroid hormones can pass to the baby safest would be to discontinue breast feeding (no problem for woman on thyroid replacement treatment)3) Cancer - breasts often become lumpy when lactating. Suspicious lumps can be biopsied under local anesthetic.

Family and Social1) Lactation is possible for multiple infants - this is concept of "wet nurse"; the problem is not the milk supply but the problem of time2) Working with lactation - 4-6 weeks needed to establish lactation - after this time the woman can express the milk

After 3-4 months feeding schedule more regular can give a supplement and discontinue one feeding

16

3) pregnancy during lactation - oxytocin can cause contractions of the uterus - possibly increased risk of spontaneous abortion

pregnancy hormones may alter the taste and decrease the amount of milk produced4) relactation possible particularly if the time is short - will depend on the mother's determination and the baby's willingness5) Some women have nursed adopted babies. This is more likely to be possible if she has recently given birth or weaned another baby. May add to the stress of an adoptive parent and should not be encouraged6) teenage mothers can breast feed but need more support

Failure to Thrive1) causes can be maternal 2) can be related to inappropriate suckling3) evaluate the growth frequently

Try to improve intake if there is a problem, if this fails add a supplement or if necessary change to bottle feeding

Common reasons for failureA) Poor maternal attitude - the choice to breast feed may not have been hers. She agreed to do it for others.B) Inadequate milk supply

1) Is mother's nutrition adequate2) Are anxieties and distractions eliminated?3) Adequate rest4) Is there a problem due to some medication she is taking that inhibits milk production or let down

C) Lack of information and support Many women do not have anyone to talk to about their experiences postpartum depression occurs around 4-5 days after birth; this may cause normal minor

problems to be blown out of proportion Good instruction and counseling and proper support can overcome these problems.

Infancy

Assessing Newborn Health Full term infants - born between 37 – 42 weeks gestation Preterm infants – born before 37 weeks gestation Infant mortality – death that occurs within the first year of life, most common causes;

o Congenital malformationso Complications related to preterm birtho Sudden infant death

17

Standard Newborn Growth:o Babies born full term (37-42 weeks) with normal growth are called Appropriate for

Gestational Age (AGA). o If they are full term and are greater than the 90 percentile they are called Large for

Gestational Age or (LGA). o If they are low birth weight (LBW) this means less than 5.5 pounds they can be either

o Preterm born less than 37 weeks gestation oro Small for Gestational age (SGA) or intrauterine growth retardation (IUGR).

These babies are born full term but small. o

Assessing Newborns: A test is done on newborn babies in the delivery room as a quick assessment of the infant’s status after birth. It is called an Apgar test and involves scoring five factors; activity and muscle tone, pulse (heart rate), grimace response (medically known as "reflex irritability"), appearance (skin coloration) and respiration (breathing rate and effort). Each factor is scored 0-2 so the score could be between 0 and 10. The test is usually done at one and five minutes, unless the score is low, then it will be done again at 10 minutes. A score <3 indicates critical condition, 4-6 fairly low and 7 and above generally are normal. It would be in the medical record as follows: Apgars 61 and 95. This means the one minute Apgar was 6 a somewhat low score, followed by a nine at five minutes, a normal score.

Growth and Maturation The infant grows rapidly the first year of life goes from reflexive sucking to self feeding changes from a diet of milk to include other beverages, table and finger foods Bonds with the parents and develops a distinct and unique personality

Growth and maturation can be compromised or accelerated by over or under nutrition during this time

Physical GrowthBirth weight

Determined by the mother's pre-pregnancy and weight gain during the pregnancy After birth genetics, environment and nutrition determine rates of gains in wt and ht After birth there is a loss of ~6% body weight (up to 10%)

o B.W. regained by the 10th day of life

Weight gain: Average wt gain 20-25 g/day to 4 months of age Average wt gain 15 g/day 4-12 months of age by 4 mos most babies double their birth weight by 12 months most babies triple their birth weight Males and smaller babies usually gain faster

Length

18

50% increase by one year of age There can be catch-up or lag down in growth after birth Catch up - babies are born small but genetically determined to be larger. Increase in

growth noted usually between 3-6 months of age Lag down - initially babies continue to grow at the pre-delivery rate then slow down and

cross growth channels - usually 9 months to 1 year.

Growth Charts accurate measurements need to be taken. Then the measurements are plotted on standard charts over time growth velocity, acceleration or deceleration can be monitored.

Most common growth standards in North America are the National Center for Health Statistics (NCHS) based on data accumulated Fels Research Institute

Birth to 36 months - one for males one for females On the axis age; on the abscissa ht or wt ranked compared to 100 other infants of similar age

National Health and Nutrition Examination Survey (NHANES) equal distribution of races includes any baby over 1500 gms www.cdc.gov/growthcharts

Changes in body compositionBody water total body water 70% at birth

1. infants have high body water content 2. high body water content makes infants susceptible to dehydration

at one year body water 60% Extracellular fluid decreases and intracellular water increases

LBM increases (contains water)

Fat increases 0.5 % at 5 months gestation 16% body fat at term fat increases until about 9 months

Changes in body proportions At birth the head is 1/4 of the total body length in adult 1/8 At birth the legs are 3/8 of the total length in the adult 1/2

Psychosocial The infant develops trust – needs to be fed immediately –

19

they do not tolerate delay after 3 months more patient, can wait better tactile stimulation important - should hold and cuddle when feeding

Digestion and absorptionFull term infant is prepared to digest and absorb an adequate supply of nutrients for growth and development

Stomach - small frequent feeding are required At birth the stomach capacity is 10-12 ml which increases to 200 ml by 12 months of age Stomach empties in 2 1/2 - 3 hrs - need frequent feedings By 24 hours of age the stomach has an acid pH

Intestines - increased surface area for absorption compared to adults proteins;

o trypsin - near adult levelo chymotrypsin - 50% of adult levelo carboxypeptidase - 50% of adult level

The amount of protein in human milk or commercial formulas is adequately digested by the infant

FATS - overall adequately absorbed and digested by infantso human milk absorb - 85-90%o cow milk absorb - 70%o commercial formulas is a blend which improves absorption > cow milk

CHO - sugars are well utilized by infantso maltase, isomaltase and sucrase fully developed by 28-32 wks gestationo lactase rises near termo pancreatic amylase - not present until 4 months of age

Renal functionThe infant has immature kidneys;

nephrons mature at 1 months of age tubules are short and narrow until 5 months of age pituitary gland produces small amounts only of the antidiuretic hormone, vasopressin,

which inhibits diuresis

Therefore, the infant has limited ability to concentrate urine

Renal solute load is the major percent of solutes presented to the kidney for excretion N-end (nitrogen) products from protein metabolism electrolytes - Na, K, P, Cl If not utilized or lost they need to be excreted

20

The potential load of the solutes to the kidney can be calculated exactly Milk provides 95 ml of water for every 100 ml consumed Some of the solutes are used for growing, some are lost in feces or evaporation The remaining solutes are dissolved in water from the diet or water formed during the

oxidation of CHO and proteins The concentrating ability of neonates maybe 700 mOsm/L. The concentrating ability of older children and adults is 1200 mOsm/L

Milliosmoles (mOsm/L) standard unit of osmotic pressure; equal to the gram molecular weight of solute divided by the number of particles (ions) into which the substance dissociates in solution.

Osmolality – refers to the concentration of solutes per unit of solvent.

Human milk provides 93 mOsm/LCommercial formula 133 mOsm/Lsoy formula 177 mOsm/L

The infant has no problem excreting the solute load provided by human or commercial formulas

Problems can occur; incorrectly prepared formula fever or increased environmental temperature increases water losses diarrhea or vomiting causes increased losses low intake

Nutrient Needs of InfantsEstimated needs are based on the following;

intakes of normally growing infants nutrient content of human milk nitrogen balance studies for amino acid requirements

DRIs - RDA's provide a margin of safety and are divided;birth to 6 months6-12 months - reduced growth in second 6 months

Energydetermined by;

body size physical activity rate of growth

range is large from one baby to the next and even within the same baby at different times Total energy needs increase during the first year of life

21

The energy per unit of body size decreases108 kcal/kg 0-6 months

98 kcal/kg 6-12 months Monitor growth to determine is energy intake is adequate

Protein and amino acidsRequirements

0-6 months 2.2g/kg (9.1 g/day)6-12 months 1.6 g/kg (11.0 g/day)

Breast fed baby gets; 2.43g/kg/day at 1 month 1.51 g/kg/day at 4 months

The American Academy of Pediatrics has set minimum protein standards for infant formula of 1.8g/100kcal with the efficiency of the protein equal to casein

amino acids - 9 essential – (phenylalanine, tryptophan, lysine, threonine, leucine, isoleucine, valine, methionine and histidine ( histidine essential in infants and children not adults).

Snyderman and Holt determined the least amount of each essential amino acid required to maintain positive nitrogen balance and promote growth when the nitrogen and other amino acids are kept constant

Fomon and Filer estimated amino acid requirements based on intakes and growth

The FAO/WHO - used the above studies to determine the upper range of essential amino acid intake

FAT and Essential FA's Fat is an important source of energy during rapid growth because of the protein sparing

effect Human and commercial contain similar amounts of fat human 55% and commercial 45-

50% Essential fatty acid - Linoleic acid Linoleic acid deficiency has been reported;

a) increased basal metabolic rateb) eczema like dermatitisc) increased caloric intake to maintain growth minimal is 1% of the total calories optimum is 4-5% of the total calories human milk provides 5 % - cow milk only 1% - commercial formulas added

Water infants have increased body water and the immature kidneys makes then vulnerable to

water imbalance The requirement is determined by water loss, water needed for growth and solutes in the

diet

22

water can be lost through; skin and respiratory tract called insensible water loss Evaporative losses, perspiration increased with fever or increased environmental

temperature. Evaporative losses are greater in infants than in adults elimination - feces and urine growth - water is used in growth of new tissues

The range of water requirements newborn 80-100 ml/kg/day > 10 days 125-150 ml/kg/day 1 year 120-135 ml/kg/day

NRC - National Research Council - recommends 1.5 ml/kcal of energy

Breast fed and commercial formula fed infants do not need supplements of water under normal conditions (abnormal losses increased need for water)

Water intoxification - Hyponatremia, irritability and coma can result from too much water. There are case reports where the babies were forced to drink 8 ounces of water after each

feeding or were given water instead of feedings. Also reported in infants given swimming lessons. Swallow water when submerged at too

young an age.

Minerals and vitamins - The RDA has been established for 3 major and 4 trace elements and 11 vitamins

MineralsCalcium –

recommended intake is based on formula fed infants who retained less than 50% of the calcium they consume

Breast fed babies retain 2/3rds of the calcium they consumeo 0-6 months 210 mg/day (AI)o 6-12 months 270 mg/day (AI)

Iron - based on prenatal reserves and food intake prenatal reserves - fetus accumulates iron in proportion to body size - preterm and LBW

have lower reserves if the mother follows a healthy diet during pregnancy the full term baby has iron reserves

that last 4-6 months full term infant has rapid growth and increased blood volume so needs are high

o At birth the Hg is 17-19g/100mlo 6-8 weeks the Hg is 10-11 g/100ml - the decrease is a result of the shortened life

span of the cells and reduced erythropoiesis - this is normal physiological

23

anemia of the newborno After 6 to 8 weeks the Hg starts to increase to a level of 13 g/100ml at 2 years of

age. o If the iron stores are depleted there may not be a rise in Hg after 6-8 weeks, this is

anemia due to iron deficiency

The most common nutrient deficiency in North Americas? - iron

Food sources absorption 49% in human milk, 10% in cow milk and 14% in commercial formula commercial formula is available with and without ferrous sulfate infant cereal has electrolytically reduced iron; absorption ~5% may be enhanced if

taken with vitamin C containing fruit or fruit juice Supplement; Breast fed babies usually have adequate stores and good absorption of iron

from the milk. At 4-6 months usually start iron fortified cereal, then no need for an iron supplement. Formula fed infants should be fed iron fortified formula from the start

RDA:0-6 months 0.27 mg AI6-12 months 11 mg RDA

Zinc stores - there are no stores of zinc only the tissue concentrations which are similar to

adults RDA - based on absorption from formula (0-6 months 2 mg/day; 6-12 months 3 mg/day)

Food sources colostrum - 3-5 times higher in zinc than mature milk commercial formulas - supplemented to provide 5 mg/L bioavailability - 59% human milk - 25-40% commercial formula

Vitamins Requirements for many are based on the intakes of macronutrients most vitamins cross the placenta and accumulate in the fetus in a concentration greater

than the mother Excess vitamins A and D greatest risk of toxicity water soluble vitamins stored only in degree of tissue saturation, turn over is rapid so a

deficiency of a water soluble vitamin can occur rapidly in a short period of time

Vitamin A recommended RDA: 0-6 months 400 ug /day 6-12 months 500 ug/day

24

Vitamin D – AI: 5 mg/day 0-12 months

Breast fed babies not exposed to the sun should be given a supplement (not done in routine care)

Vitamin E – RDA0-6 months 4 mg/day6-12 months 5 mg/day

Vitamin K - essential factor for prothrombin and other clotting factors newborn has a low level human milk is low in vitamin K Hospital born babies receive 0.5-1.0 mg Vitamin K – IM (intra-muscular injection) Home deliveries may need a supplement

Requirements of thiamin and riboflavin are based on energy intakesthiamin 0-6 m 0.2 mg/day; 6-12 m 0.3 mg/dayriboflavin 0-6 m 0.3 mg/day; 6-12 m 0.4 mg/day

niacin tryptophan can be converted to niacin therefore it is difficult to determine needs RDA

0-6 m 2 mg/day6-12 m 4 mg/day

pyridoxine - B6 pyridoxine recommended intake is based on protein intake

B12 cobalamin - essential for the transfer of single carbon fragments from one amino acid to another and

nucleic acid synthesis deficiency causes growth retardation and impaired neurological development can occur in a mother who is a strict vegetarian or a woman with pernicious anemia

folate The level of folate decreases by two weeks of age and remains low through the first year

of life Goat milk is deficient in folate

vitamin C - recommended amount is that found in human milk

Supplements: Breast fed baby - vitamin D supplement can be given at about 2 months if no exposure to

sun (not done routinely) commercial formula fed infants should be given formula with Fe due to prevalence of

25

iron deficiency If breast fed baby is given Fe-fortified cereal between 4-6 months no need to supplement

Fe

fluoride - if fluoride is not supplemented in the water or if the baby is breast fed can give supplement (not done routinely)

Milk for infantsHuman milk and formulas

Most health care professionals recommend breast feeding because of the advantages discussed earlier

Even short term breast feeding then switching to commercial feeding is desirable cow milk formulas try to simulate human milk

American Academy of Pediatrics (AAP) Standards:The AAP issued infant formula guidelines after a manufacturer was found to have made a soy formula without chloride. The company knowingly made the formula chloride deficient because it would have required an extra step in the manufacturing process to add the chloride (reduced profit margins).

In 1976 the AAP issued recommendations for commercially prepared infant formulas The minimum nutrient amount is closest to human milk Maximum is for LBW or sick infants where nutrient requirements may be higher

Modified Cow's Milk Formulas The protein and mineral content are reduced to decrease the renal solute load The curd tension is reduced by homogenization and heating (add acid to casein forms a

curd like cottage cheese) Some formulas add whey to make the whey-casein ration similar to human milk Vegetable oils and carbohydrates are added to make calories similar to human milk vitamins and minerals are added formulas are prepared with and with-out ferrous sulfate (12 mg iron/qt)

Hypoallergenic formulasThe most common is soy

Soy formula is made of protein isolated from the soy meal and supplemented with methionine

The trypsin inhibitor is inactivated by the heat process Protein is not well utilized so additional protein added The goitrogenic effect is overcome by heating and addition of iodine CHO's are usually corn syrup solids or sucrose Soy or other vegetable oils to make calorie content similar to human milk

Casein hydrolysate formulas are for infants who do not tolerate cow based formula or soy formula (very expensive)

26

The formulas are more elemental - components are easier to digest - used for very sick infants

These formulas are very expensive, taste may be a problem depending on the age of the infant

Nutramigen – casein hydrolysate (CH), modified tapioca starch (MTS), sucrose and corn oil

Pregestimil - CH, MTS, corn syrup solid (CSS), medium chain triglycerides (MCT), corn oil

Alimentum - free amino acids, sucrose, MTS, MCT, safflower and soy oil

Formula for older infants There is no need for a special formula for ages 6-12 months There are two available but not endorsed by pediatricians or health care professionals Cow milk is discouraged until after one year of age - May lead to anemia.

o low iron content in cow milko occult blood loss related to cow milk ingestiono Infant formula should be continued until one year of age

Formula preparationThree basic types available

Liquid concentrate - must be diluted with equal volume of water (13 ounce can) Ready to feed - comes in 4, 6 and 8 ounce bottles and a 32 oz can powdered formula- 1 level Tablespoon should be mixed with 2 ounces of water

Errors in mixing Diluting ready to feed formula lead to growth failure or failure to thrive (FTT); this may

be doneo by error, bought the wrong kindo belief that the baby will spit up less

Feeding undiluted formula can be a more serious problem. o This lead to increased intake of calories, solutes and protein.o Can lead to hypernatremic dehydration and metabolic acidosis, tetany, cerebral

damage and gangreneo often occurs in powdered formulas combined with increased losses due to fever

or illness

Sterilization of formulaThere are two techniques that are both equally effectiveTerminal sterilization -

Wash and rinse all bottles and equipment Wash can and open Add formula and appropriate amount of water to the bottle (s) Cover bottles with inverted nipple and loose collar Put bottles in the kettle/sterilizer and fill with 3 ounces of water. Cover and boil for 20

27

minutes. Remove from kettle, cool to touch, then refrigerate. Use within 48 hours

Clean (aseptic) technique Place bottle and equipment in boiling water for 5 minutes, let cool. (Dishwasher will

also be effective) Place water in a pan boil and cool Wash can add formula into sterilized measuring cup add desired amount of sterilized water pour into sterilized bottles (or plastic bottle liners), place the inverted nipples, collars and

caps using tongs. Use within 48 hours.

(It is also possible to use plastic liners and sterilize bottle holder, nipples collars and caps in dishwasher.)

Warm milk mixed with saliva of baby is a good medium for growth of bacteria. After feeding discard remaining formula.

Semisolid food in the infant’s dietSemi-solid foods are often given in the first month of life

parents feel it will increase sleeping at night feel the baby is hungry developmental landmark

Age of introduction has changed In the 1920's solid foods were introduced after 1 year of age In the 1950-1960 there was a trend to introduce solid foods early, a few weeks or months of age. This was mainly to provide an early source of iron Currently, solids are recommended between the ages of 4-6 months.

o This is when the infant has the developmental skills to eat the food o Can exhibit sign of fullness (refusing food) may prevent obesity. o reduced food allergies when introduction of solids is at a later age.

Feeding Behaviors Developmental readiness - Illingworth and Lister have described a "critical or sensitive"

period of development At 6-7 months the infant is ready to chew. If solid foods are withheld they will have a

more difficult time learning this at a later time

Development of Oral Structures and Functions The neonate is prepared to suck and swallow at birth The oral structures and sucking method mature and change during the first year A newborn infant sucks reflexively, a 2-3 week old infant suckles

28

Negative pressure created when nipple is in the infants mouthlower jaw and tongue work together to remove milk; up and down motion

An older infant has a mature suckdiffers in the movement of the lips, tongue and gum pads; the tongue moves back and forth rather than up and down

Sequence of Development of Feeding Behavior Newborns have a "rooting reflex" to help them find the breast, suck and receive

nourishment stroking the skin around the cheeks and lips causes the baby to turn toward the stimulus

so the mouth comes in contact with it Tonic position while feeding - head rotated to one side, that arm fisted other arm

extended Nourishment obtained by a rhythmic movement of the tongue; semi-solids are often

expelled from the mouth due to this movement of the tongue

Age 16-24 weeks (4-6 months) mature suck can draw in the lower lip as spoon is removed tonic neck position faded, more symmetric position with head in midline hands can close over bottle 6 months can grab for an object and bring it to the mouth

Age 24-28 weeks (6-7 months) up and down chewing movement of the jaw since they can already grasp objects and bring to mouth and sit indicates readiness to

finger feed palmar grasp - cookies, crackers, melba toast

Ages 28-32 weeks (7-8 months) can control trunk and sit without support can use the shoulders and arms better grasp is digital can transfer items from one hand to another, learns how to release can bring head forward, take food from spoon by pressing lips against spoon, drawing

head away and drawing in the lower lip aware of cup and can drink from it but a lot spills due to projection of the tongue before

swallowing By 28 weeks the infant can hold the bottle and feed themselves but they will not learn to

tip it back until 32 weeks

Ages 6-12 months Solid mashed but not strained food is appropriate, may be critical to introduce this

texture at this time food items need to be easily manipulated and swallowed

29

ground meat in a sauce or gravyice-cream, custardsminced livers or tunaavoid small pieces of rice or corn which could be aspirated

9-12 months - ready for self feeding develop a pincer grasp can feed from bottle alone can drink from cup with help by one year rotary chewing understand container/contained voluntary hand to mouth movements can release and rescue objects

Food Choices

Commercially Available Foods

A variety of foods are available; flaked or freeze dried, canned and frozen

Jarred single foods first foods - 2 1/2 ounce size second foods - 4 ounce size third foods - 6 ounce size Dinners of mixed meat and vegetable

Juices in 4, 8 and 25.3 ounce bottles.

Junior foods and toddler foods with increased texture and increased ingredients

Food selectionFoods should be started at 4-6 months depending on readiness

first food is cereal - due to iron start very dilute so no aspiration; when baby is able to eat from the spoon without

pushing food out of the mouth start with rice cereal - least allergenic

Next either fruits or vegetables - new foods should be added singly, no more than one new food every three days

carrots, beets and spinach contain nitrates and should not introduced until well after 4 months. Nitrates can be converted to nitrites in the stomach resulting in methemoglobin (blocks the oxygen carrying capacity of hemoglobin)

Fruit juice can be started when infant is ready to drink from the cup (dilute 1:1 with water) and give in limited amounts (about 2-4 ounces/day)

30

Foods as a source of nutrients

Cereal is usually the first food added to the diet Dry cereal with electrically reduced iron - 3 level Tbsp = 5 mg iron Cereal and fruit mixtures are fortified with ferrous sulfate to provide 7-9 mg/ 4.5 oz. jar Strained and junior fruits and vegetables provide vitamin A and vitamin C Vitamin C is added to several fruits and juices Some fruits have sugar added and are marketed as desserts Tapioca is added to a number of fruits Milk is added to creamed vegetables wheat is added to mixed vegetables Strained and junior meats are prepared only with water except lamb which has lemon

added Meats are an excellent source of heme iron Mixed foods should be introduced later after it is determined that there are no allergies to

single foods Desserts contain sugar, modified corn or tapioca starch

Home preparation of infant foods

Primary reason used to be to avoid salt and sugar in commercially prepared foods. Now this is not a problem. Home prepared has more salt and sugar than commercial baby foods.

Home preparation: (see book) Everything needs to be cleaned. Food needs to be prepared in such a way to maintain the most nutrients Avoid addition of sugar or salt refrigerate or freeze in small individual servings.

Table food Cultural influence - culture affects the type of food and the timing of introduction Solid foods need to be easy to chew and masticate choking can occur on small pieces of hot dogs,grapes, hard candy, nuts and other food in small pieces honey; has been infected with spores of clostridium botulism which are not inactivated

by heat. The spores germinate in the intestine into the toxin therefore should not be given to infants less than 1 year of age.

Feeding the infant

31

Feeding schedule newborn fed 6-8 times per day or every 2 to 4 hours, usually 20 minutes for a feeding

and they consume 2-3 ounces at a feed at 2 weeks of age the infant will have increased the amount per feed and decreased the

number of feedings to about 6 per day 2 months of age usually 5 feedings per day and sleep through the night 6 months 3 meals and 4 milk feedings per day

Intake of infants infants requirement for maintenance, growth and activity also parents sensitivity and willingness to accept cues of hunger and satiety eagerness of the infant to feed skill at feeding

Growth and response to feeding formula fed babies regain their birth weight faster after 3-4 months of age formula fed babies gain more rapidly The greatest consumption of energy per unit of body size is between 14 and 28 days

Feeding-related concerns

Colic - healthy babies who cry constantly for several hours, draw their legs up to their abdomens and pass gas.

Sometimes a change of formula may help (from one milk based commercial formula to another);

in breast fed women avoid gas forming foods.

Spitting up - this is a normal common problem. Most babies spit up a small amount after each feeding, the volume can seem like a lot

because it is mixed with gastric juices. Normal growth indicates that it is not a serious problem. It is usually due to incomplete closure of the gastro-esophageal sphincter (matures with

time) The problem resolves when the baby can sit alone.

Nursing Bottle Syndrome - This is a characteristic pattern of tooth decay in infants and younger children, where all the upper and the lower posterior teeth are affected.

The infants/toddlers are sent to bed with a bottle. The liquid drips in the mouth when they fall asleep. The tongue falls forward and protects the lower teeth. Saliva stops once the baby falls asleep and the sweet liquid remains around the other teeth - promotes tooth decay.

32

Infant obesity - speculation that formula feeding and/or early introduction of solids may lead to obesity.

Neither breast feeding, bottle feeding nor time at introduction of solids has been shown to cause obesity.

There is no relationship between obesity in infants and obesity later in life