66 terms

Unit 9- Nutrition and Infancy

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Infant vs. Neonate
Infant: a very young child who has not yet begun to walk or talk- typically in the first one year after birth
Neonate: newborn baby in the first month of life; can only suckle, swallow, and take in small amounts of liquid foods
What development occurs during the first year of life?
-body weight increases by about 200%
-by the first 6 months, birth weight doubles, by year 1, birth weight normally triples
-body length increases by about 55%
-head circumference increases by ~40%
-brain weight also doubles
*due to this extreme growth and development, nutrient requirements per kg of body weight is highest than any other time in life
2 commonly used metrics on growth charts
1. length-for-age and weight-for-age
2. head circumference-for-age and weight-for-length
true or false:
growth charts are intended to be used as a sole diagnostic instrument
false
-should be used to form an overall clinical impression of the child's well-being
-should be used along with:
--biochemical data
--hematological tests
--health and medical records
--dietary intake data
Infant Nutritional Needs:
Carbohydrates
-supply energy for growth, body functions, and activity
-allow protein in the diet to be used efficiently for building new tissue
-allow for the normal use of fats in the body
-provide the building blocks for some essential body compounds
major carbohydrate consumed by normal young infants
Lactose
-from breast milk and/or cow's milk based infant formula
-digested by the enzyme lactase found on the tips of enterocyte villi
-undigested lactose is metabolized by bacteria in the gut; this lowers the pH and protects from potential pathogens
Lactose intolerance
-results from an imbalance between the amount of ingested lactose and the capcity for lactase enzymes to hydolyze the disaccharide
-results in the accumulatin of lactose in the small intestine
-lactose is osmotically active and draws water into the lumen of the small intestine
-this then goes to the large intestine which uses the lactose for their own metabolism, releasing 2- and 3- carbon products (such as acetic acid and lactic acid), CO2 and H2 gas
-the 2- and 3- carbon pdts are also osmotically active, further drawing lots of water into the large intestine
-end result: osmotic diarrhea and large amounts of CO2 and H2 gas (H2 gas in breath can be used as an indicator of lactose intolerance)
*affected infants should be placed on a lactose-free diet
true or false:
lots of fruit juice is good for the infant
false
Up to 6 months: NO fruit juice
Over 6 months: no more than 4-6 ounces
-infants and toddlers who drink excessive amounts of juice suffer from diarrhea, abdominal pain, or bloating
-chronic nonspecific diarrhea may be caused by consumption of fruit juice due to their high concentration of sorbitol and higher ratio of fructose to glucose
--fructose and sorbitol absorption is poor and passed into the large intestine where they are osmotically active and draw in a lot of water in the large intestine: osmotic diarrhea
-these sugars also undergo bacterial degradation causing fermentative diarrhea (loose acidic stools with high CO2 and H2 release)
true or false:
Honey is recommended for infants below 1 year
False
-due to risk of Clostridium botulinum infection
-this can lead to infant botulism with serious consequences
recommended fiber in the infant diet
-NO fiber n the first 6 months
-very GRADUAL intro of fiber through whole-grain foods, fruits, and vegetables
-5 g/day by 1 year of age is recommended
-requirement are not well established
true or false:
late gestation and infancy is the time of highest protein accretion in human life
true
What must the infant's protein source contain?
-any differences in preterm infant?
-the essential amino acids (histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine)
-Preterm: two additional amino acids: cystine and tyrosine are required for preterm infants because enzyme activities involved in their synthesis are immature
What is the major source of energy in breast milk and infant formula?
Lipids
-promote the accumulation of stored fat in the body which serves as insulation to reduce body heat loss, and as padding to protect body organs
-allows for absorption of the fat soluble vitamins A, D, E, and K
-provides essential fatty acids
Essential fatty acids for infant
Required for normal brain development, health skin and hair, normal eye development, and resistance to infection and disease
-Essential: 18C linoleic acid (LA) and a-linolenic acid (ALA): small amounts must be provided in diet
-If LA and ALA are deficient in the diet, then the long-chain (20C) polyunsaturated fatty acids (LCPUFA) arachidonic acid (ARA) and docosahexenoic acid (DHA) become essential
true or false:
breast milk has significant amounts of cholesterol and infant formula has none
true
-in recent years, it has been of interest is this is a benefit or adverse effect
-breast feeding has been associated with a protective effect against CV disease
true or false:
vitamin and mineral supplements are necessary in the first years of life for normal children
false
-excessive amounts of supplements are toxic or even fatal to infants
-mother's nutritional status is very important for exclusively breast-fed infants
In general, what vitamins is breast milk low in?
Vitamin K and Vitamin D
-all infants are given an IM injection of vit K at birth
-vit D deficiency also affects Ca and P absorption: will affect bone and tooth formation in the infant
What does vitamin D deficiency in infant lead to?
Rickets
-swollen joints, poor growth, bowing of the legs or knocked knees
-soft spot on baby's head is slow to close, bony necklace, curved bones
What infants are at risk for vitamin deficiencies
-infants on a vegan or strict vegetarian diet are at risk for Vit B12 deficiency
-pre-term infants have lower stores of vitamin and minerals (ie. Fe) and are prone
-infants with milk, fruit, and vegetable allergies are also at risk
fluoride in infants
-not an essential nutrient but is beneficial for teeth strength and protection from tooth decay
-excess consumption leads to dental fluorosis
true or false:
supplemental water is NOT recommended in the first 6 months of life
true
-water needs are met from breast milk/formula
-supplemental water will dilute Na and other ions and lead to potentially dangerous electrolyte imbalance
-excess water by infant leads to water intoxication and causes seizures, coma, brain damage, and death
-water should be introduced with solid foods (after 6 months) to maintain renal solute load
true or false:
breast feeding is the optimal mode for infant nutrition
true
-American Academy of Pediatrics strongly recommends exclusive breast feeding for the first six months of life and that breast feeding continue for at least 12 months
main advantages of breast-feeding to the infant
- Meets all nutritional needs
- Breast milk has growth factors and hormones to assist development
- Easily digested
- Provides immunity
- Enhanced neural development
- Leaner and less prone to obesity as adults
- Contributes to proper development of jaws and teeth
- Fewer food allergies & intolerances
main advantages of breast feeding to the mother
- Maternal weight loss: Lactation requires 450-500 Kcal/day (50% from diet, 50% from
adipose)
- Convenient
- Decreased risk of breast and ovarian cancer
- Uterus returns to normal size sooner
- Decreases postpartum blood loss
- Less depression
- Infant-mother bonding
- Less expensive as compared to formula feeding.
true or false:
breast milk quality depends on Mother's diet
true
Nutritional recommendations for a breast-feeding mother are:
Drink approximately 64 oz of fluids per day.
The nursing mother requires an additional 500 calories and 20-30 g of protein a day.
Supplements: prenatal vitamins with iron is recommended
The mother need not to avoid certain foods unless she observes consistent increased
fussiness in the baby in association with the mother ingestion such foods.
Garlic, onions, cabbage, chocolate etc.
Great quantities of caffeine
Alcohol: guidelines are not clear, it may end up in breast-milk & is best avoided
lactation
-where are hormones released
-hormones involved
-Accomplished through the release of hormones from the PITUITARY GLANDS signaled to be released from nursing
-Hormones: prolactin and oxytocin
lactation:
prolactin
-as the baby suckles, impulses pass from the areola up to the hypothalamus then to the anterior pituitary producing prolactin which stimulates the breasts to produce milk
lactation:
oxytocin
-suckling also stimulates the production by the posterior pituitary
-oxytocin causes contraction of the smooth muscles surrounding the alveoli, squeezing milk out
mammary epithelial cells (MEC)
-primarily responsible for converting most precursors into milk constituents that are found in breast milk
-milk compounds cross the mammary gland plasma membrane through five different pathways
Milk compounds crossing the mammary gland plasma membrane:
Pathway I
-DIRECT movement of monovalent ions, water, glucose, drugs and xenobiotics across apical and basal membranes of MEC via TRANSPORTER PROTEINS.
Milk compounds crossing the mammary gland plasma membrane:
Pathway II
-milk fat and lipid secretion with formation of cytoplasmic lipid droplets moving to the apical membrane for release as milk fat globules (MFG). These globules are
surrounded by the phospholipid bilayer derived from the MEC.
Milk compounds crossing the mammary gland plasma membrane:
Pathway III and IV
EXOCYTOSIS and VESICULAR TRANSCYTOSIS: for the release of proteins from the MEC
Milk compounds crossing the mammary gland plasma membrane:
Pathway V
-transport through the PARACELLULAR PATHWAY for plasma components and leukocytes, respectively
*all the pathways are illustrated on slide 8
Colostrum
-the concentrated, yellowish milk, produced in small quantities during the first few days (~5 days) after giving birth
Some of the characteristics are:
It is very rich in proteins, vitamin A, and sodium chloride, but contains lower amounts of carbohydrates, lipids, and potassium than mature milk.
It contains anti-microbial factors such as immune cells (e.g. lymphocytes) and antibodies sIgA. It also contains lactoferrin, lysozyme, lactoperoxidase, and proline-rich polypeptides for protection against pathogens.
Growth factors present in the colostrum stimulate the development of the gut
It has a mild laxative effect, encouraging the passing of the baby's first stool, which is called meconium
meconium
-baby's first stool
-promoted by the mild laxative effect of the colostrum
Major components of human milk:
B-lactose
-primary carb found in human milk
-lower in colostrum
-lactose is a slowly absorbed sugar; prolongs the passive, vit D-independent absorption of calcium in the ileum (esp. important in infants where vit D levels are low)
-lactose is "fermented" in the baby's colon creating an acid environment (low pH increases the solubility of Ca and thus its bioavailability)
Major components of human milk:
Human milk oligosaccharides (HMO)
-2 types
-free oligosaccharides are mostly lactate-based; about 85 different types are known
-glycans: oligosaccharide chains attached to proteins
-infants lack the enzymes needed for HMO digestion
beneficial effects to the infant of HMOs
-May promote the growth of beneficial microflora
-Provides protection against pathogens: Most enteric pathogens use enteric-cell-surface glycans to identify and bind target cells as critical first step in pathogenesis. HMO act as soluble-decoy receptors. Pathogens bind HMOs rather than infant mucosal surfaces HMO and bound pathogen excreted in stool, decreasing risk of bacterial, viral and protozoan infections
Major components of human milk:
Human milk proteins
-human milk proteins are of two types casein and whey proteins
Casein
-family of proteins that precipitates at low pH in the stomach
-phosphoprotein, forms micelles with Ca thus increasing the bioavailability of Ca
-this conversion to a solid slows down gastric emptying and prolongs the time between feedings
-during early lactation, levels are low, but are gradually increased over time
Whey proteins
Remain in solution at acidic pH
Major components of whey are:
-a-lactalbumin
-lactoferrin
-immunoglobins
-lysozyme
-serum albumin
Component of whey protein:
a-lactalbumin
-strongly binds Ca and An ions and may possess bactericidal activity
Component of whey protein:
lactoferrin
-largely excreted in feces
-inhibits the growth of Fe-dependent bacteria in the GI tract
Component of whey protein:
immunoglobins
-largely excreted in feces
-protects the infant from viruses and bacteria
Component of whey protein:
lysozyme
-enzyme that hydrolyzes outer cell walls of some gram-neg bacteria
-protects the infant against E. Coli and salmonella, etc.
-promotes the growth of healthy intestinal flora and has anti-inflammatory functions
Component of whey protein:
serum albumin
-acts as a ligand that binds to Zn, Cu, fatty acids, and other small moleucles
Major components of human milk:
Antigen specific secretory IgA (immunoglobin A)
-prevents adherence and penetration of specific microbes in the baby's GI tract
-after ingesting a microbe, the mother's immune system produces antibody molecules termed sIgA that enter the breast milk and help protect the baby from pathogens
-protected by digestion in baby's GI tract by pancreatic proteases
-only works in the lumen of the baby's GI tract and there is no evidence of sIgA being taken up from the GI tract into the circulation
Bioactive components of the human milk:
Epidermal growth factor (EGF)
-intestinal maturation and repair
Bioactive components of the human milk:
neuronal growth factors
-brain-derived neurotrophic factor (BDNF), glial cell-line derived neurotrophic factor (GDNF), ciliary neurotrophic factor (CNTF)
-promote growth and development of the enteral nervous system
Bioactive components of the human milk:
insulin-like growth factor and related proteins
-important for tissue growth
Bioactive components of the human milk:
vascular endothelial growth factor (VEGF)
-regulation of the vascular system
Bioactive components of the human milk:
growth-regulating hormones
-calcitonin and somatostatin
Bioactive components of the human milk:
hormones that regulate metabolism
leptin, ghrelin, adiponectin, etc
-these factors are important in regulating food intake and energy balance
-adults who were breastfed are leaner, on average than those who were formula fed
Human milk lipids
-the major lipid found in human milk is TAG with short chain fatty acids
-the fatty acid at position 2 is usually palmitic acid while position 1 and 3 have oleic acids
digestion of human milk lipids
Occurs by the action infant LINGUAL and GASTRIC LIPASE
-act in stomach and have acid pH optimum
-preferentially hydrolyze short- and med- chain TAGs (abundant in milk fat) and these fatty acids are more soluble than long-chain fatty acids (no bile salts in stomach)
*pancreatic lipase is present, but does not reach adult activity levels until one year old
**BSSL is also present and promotes lipid digestion (next card)
Bile salt-stimulated lipase (BSSL)
-anchored to surface of fat globule by bile salts
-occasionally will hydrolyze milk fat in stored breast milk
Contraindications to breast feeding:
maternal reasons
-Chronic diseases like blood circulation insufficiency, kidney or liver problems
Infections: HIV, CMV, HSV with lesion on breast, active infections like TB and sepsis, etc.
Psychical disorders as epilepsy, schizophrenia, depressive psychosis, postpartum psychosis.
Taking certain medications
Substance-abuse (drugs, alcohol, marijuana, cocaine, heroin, etc.)
Contraindications to breast feeding:
infant health reasons
Lactose intolerance: lactase deficiency
Hypergalactosemia: deficiency of galactose metabolism enzymes
Phenylketonuria
Contraindications to breast feeding:
social reasons/personal preferences
-yup, some women dont like it
breast milk pumped and stored
-in some cases where breast feeding is not possible, this is
-recommended that mother use clean containers to collect and refrigerate immediately
-breast milk is stable at 4 degrees celsius for up to 48 hours and when frozen for several months
true or false:
cow milk can be used as a substitute before age 1
false
-cow milk has a-lactase rather than B-lactose: less beneficial and greater risk of lactose intolerance
-risk of cow milk protein allergy
-a-lactoalbumin rich in tryptophan, is limiting in cow milk
-electrolyte imbalance due to high levels of Na, P, and Ca
-iron deficiency anemia at greater risk: due to intestinal blood loss, inhibition of non-heme Fe absorption by Ca and casein, and low Fe iron content with low bioavailability
-antibodies and bioactive compounds are missing
-there are 5 times more essential fatty acids in breast milk than in cow milk
Infant formula is often based on cow milk components and the added ingredients include:
Carbs
-B-lactose
-sucrose or glucose if child is lactose or galactose intolerant
-dexrin-maltose: to imporve the growth of bifidum-bacteria
Infant formula is often based on cow milk components and the added ingredients include:
Lipids
-cow milk fat is replaced with vegetable oil, palm oil, and/or coconut oil (mimic the short- and med- chain fatty acids found in human milk)
-ARA and DHA are also added
Infant formula is often based on cow milk components and the added ingredients include:
proteins
-purified whey and casein from cow's milk is added
-soybean proteins are used as a protein source for infants allergic to cow's milk proteins
-partially or extensively hydrolyzed proteins, or free amino acids for special formulas for children with protein allergies
-taurine is added
Infant formula is often based on cow milk components and the added ingredients include:
nucleotides
-are added and may help establish diurnal sleep-wake rhythm in infants
Infant formula is often based on cow milk components and the added ingredients include:
vitamins
-vitamin K and D are also added
-contains 30-100% more calcium than human milk; overcomes higher bioavailability of Ca in human milk
-Iron: ferrous sulfate along with significant quantities of vit C are used to ensure bioavailability of Fe
-Selenium is added to formula to match levels in human milk