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Perfect Evolutionary Food:
Breast MilkGeza Bruckner, PhD
Professor Clinical Nutrition
Division of Clinical Nutrition
Graduate Center for Nutritional Sciences
Objectives
• To introduce the audience to some of the myriad of bioactive compounds in human milk
• To differentiate between the nutrient content of human versus cows milk and infant formulas
• To elucidate the role of n3 fatty acids found in breast milk
• To illuminate the importance of oligosaccharides in breast milk
• To impart knowledge to the audience regarding breast milk’s composition and the bio-functionality of it’s constituents
Human milk, being the sole source of early
infant nourishment, has evolved as a result of
200 million years of Darwinian pressure on
mammalian lactation to become the perfect
species specific
neonatal nutrient.
Human milk components while nourishing
growth of the infant also provide a myriad of
bioactive compounds that modulate the immune
system, cognitive development, protection from
toxins and pathogenic diseases, and remarkably
the establishment of the intestinal microbiota.
Benefits of Breast Milk
• The most important short-term immunological benefit of breast-feeding is the protection against infectious diseases
• Another consistent findings of breast-feeding is a positive effect on later intelligence tests with a few test points advantage for breast-fed infants
– Plausible explanations include the LCPUFA content of human milk
– Stimulation and reinforcement of beneficial maternal behaviors during breast-feeding.
J. Nutr. 137: 503S–510S, 2007
Benefits of Breast Milk
• There is also some evidence of
– lower prevalence of:
• inflammatory bowel diseases,
• childhood cancers, and
• type I diabetes
– small protective effect for developing overweight and obesity
– Blood pressure and blood cholesterol seem to be slightly lower
– Slightly taller as adults
J. Nutr. 137: 503S–510S, 2007.
Antibodies and Other Defense Agents
in Human Milk• sIgA1 (polymeric IGA) – protective against E. coli, S. pneumoniae, influenza
viruses, etc.
• Leukocytes
• – B lymphocytes
• – Macrophages
• – Neutrophil
• – T lymphocytes*
• Oligosaccharides - prevent attachment of H. influenzae and S.pneumoniae to the respiratory epithelium - N-acetyl-glucosamine
• Bifidus factor - specifically enhances the growth of bifidobacteria in intestines of neonates - N-acetyl-glucosamine
• Lysozyme - lyses mostly gram-positive and few gram-negative bacteria
• Lactoferrin - bactericidal, antiviral, anti-inflammatory and modulates cytokine function
• Interferon-γ * - activation of intestinal T lymphocytes to enhance mucosal immunity
• Nucleotides* - enhance intestinal repair and potentiate the immune response to certain vaccines
• Cytokines*
*Factors that potentially may impart an imprint on the child’s own immune system.
Microbial phagocytosis, production of
lymphokines and cytokines, interaction and
enhancement with other protective agents
Benefits of Breast Milk
• Some of the effects of breast-feeding on the child’s
risk of acquiring infectious diseases continue after
breastfeeding is terminated.
– Protection against
• Haemophilus influenzae type B may last for 10 y
• respiratory tract infections for 7 y
• against otitis media for 3 y and
• against diarrhea for 2 y, accompanied by a reduced rate of hospital
admission
Int J Epidemiol. 1997;26:443–50
Int J Epidemiol. 1999;28:152–6
BMJ. 1998;316:21–5.
BMJ. 1990;300:11–6.
Milk Adapting to Need
• Human breast milk changes over the period of a few months. These changes in composition parallel the babies nutrient needs.
• Colostrum (late pregnancy, first week after child birth)
– Three times as much protein as mature milk.
– Low in fat and sugar
– Acts as a natural laxative helping the
– baby pass merconium.
– More antibodies
Milk Adapting to Need
• Colostrum also contains numerous growth factors, such as:
– insulin-like growth factors I, and II,
– transforming growth factors alpha, beta 1 and beta 2,
– fibroblast growth factors,
– epidermal growth factor,
– granulocyte-macrophage-stimulating growth factor
– platelet-derived growth factor,
– vascular endothelial growth factor,
– colony-stimulating factor-1
Milk Adapting to Need
• Transitional Milk is the milk made after
colostrum and before mature milk
(sometime between day 6 and day 14 after
birth).
– Its composition is somewhere between
that of colostrum and mature milk.
Mature Milk
Milk Adapting to NeedHuman Foremilk compared to Hind-milk
Milk/Formula Macro-Nutrient Comparisons
Nutrient/
100 gram
Breast
Milk
Cow
Whole
Milk
Formula
Pedisure
Formula
EnfamilFormula
Similac
Energy
kcal
70 71 99 71 78
Protein
gram
1.03 3.15
~3X
2.86
~2.5X
2.00
~2X
2.12
~2X
Lipid
gram
4.38 3.25
~3/4
2.86
~1/2
2.00
~1/2
2.12
~1/2
Sugars
gram
6.89 5.26
~3/4
10.50
~1.5X
7.40 8.20
Milk/Formula Nutrient ComparisonsNutrient/
100 gram
Breast
Milk
Cow
Whole
Milk
Formula
Pedisure
Formula
EnfamilFormula
Similac
Ca
mg
32 113
~4X
93
~3X
86
~3X
163
~5X
Fe
mg
.03 .03 1.34
~44X
1.28
~44X
.29
~9X
Mg
mg
3.0 10.0
~3X
19.0
~6X
6.0
~2X
9.0
~3X
P
mg
14.0 84.0
~6X
76.0
~5X
47.0
~3X
91.0
~6.5
K
mg
51.0 132.0
~3X
125.0
~2.5X
75.0
~1.5X
101.0
~2X
Na
mg
17.0 43.0
~2.5X
36.0
~2X
6.0
~1/3
34.0
~2X
Inadequacy of Cows Milk
• Whole cow's milk does not contain sufficient vitamin E, iron, or essential fatty acids, which can make infants fed on cow's milk anemic.
• Whole cow's milk also contains excessive amounts of protein, sodium, and potassium which may put a strain on an infant's immature kidneys.
• The proteins and fats in whole cow's milk are more difficult for an infant to digest and absorb than the ones in breast milk
• Evaporated milk may be easier to digest due to the processing of the protein but is still nutritionally inadequate.
• A significant minority of infants are allergic to one or more of the constituents of cow's milk, most often the cow's milk protein.
• These problems can also affect infant formulas derived from cow's milk.
Breastfeeding also provides health
benefits for the mother
• It assists the uterus in returning to its pre-
pregnancy size and reduces post-partum
bleeding
• Assists the mother in returning to her pre-
pregnancy weight.
• Reduces the risk of breast cancer later in life
n3 Fatty Acids and Breast Milk
• Why are n3 fatty acids important to the developing
fetus and the neonate?
– Needed for Brain Development
• Brain cortex in infants contains 8.5 ± 1.2 DHA in Breast Feed
infants versus 7.5 ± 0.8 DHA in Formula Fed (wt%)
• Retina contains ~ 12% DHA
• During the third trimester, approximately 50 to 60 mg/day of
maternal DHA stores are transferred to the fetus via the placenta
Am J Clin Nutr l994;60:l89-94.J Am Diet Assoc. 2009;109:668-679.
H3C COOH
C18:3 w-3
w-3 family
a-LinolenicFlaxseed Oil
Canola Oil
Soybean Oil
COOH
C20:5 w-3 Eicosapentaenoic
EPA
H3C
COOH
C22:6 w-3 Docosahexaenoic
DHA
H3C
Essential Fatty Acid Families
Oily Fish
Fish Oil Capsules
H3C
H3C
COOH
COOH
w-6 family
C20:4 w-6
C18:2 w-6 Linoleic
Arachidonic
Eicosanoids
Thrombotic
Inflammatory
Corn Oil
Safflower Oil
Sunflower Oil
Eicosanoids
Less thrombotic Less inflammatory
Meat, Eggs,
Brains
Milk fatty acid composition in first month of lactation (% wt/wt)
Selected
Fatty Acid
Colostrum Transitional
Milk
Mature Milk Formulas
Average 10
18:2n6 LA 16.10 15.74 16.59 15.0
20:4n6 AA 0.74 0.67 0.53 0 to 0.22
22:4n6 0.44 0.23 0.15 ND
Total n6 18.89 17.79 18.33 15.1
18:3n3 ALA 0.41 0.58 0.75 2.0
20:5n3 EPA 0.19 0.11 0.10 0 to 0.04
22:5n3 0.35 0.23 0.15 ND
22:6n3 DHA 0.56 0.50 0.29 0 to 0.28
Total n3 2.10 1.80 1.50 2.3
SFA total 44.66 45.05 45.49 43.00
MUFA 42.29 38.59 39.63 40.00
PUFA 20.34 19.26 19.71 15.00
EJCN December 2002, Volume 56, Number 12, Pages 1242-1254
n6 and n3 PUFA Glycerol Position
SN2
Milk Fatty Acids in the Sn2 Position %wt/wt
FA C TM MM F
20:4n6 1.16 0.88 0.67 ND
20:5n3 0.33 0.28 0.27 ND
22:6n3 0.93 0.81 0.64 ND
EJCN December 2002, Volume 56, Number 12, Pages 1242-1254
Summation of Studies on n3 and Neonatal Development
Breast Milk vs Formula Fed
• Most studies show improved cognitive scores
• Most studies show improved vision
! Note: improvement in cognition and vision was negated by
alcohol or marijuana use by the mother
Food and Nutrition Bulletin
Volume 17, Number 4, December 1996
Recent Study: Effect of DHA Supplementation During
Pregnancy on Neurodevelopment of Young Children
• Key Points
– STUDY - At 18 months detected no brain development benefits in those born to mothers who took 800mg of omega-3 DHA daily from gestation week 21 to birth.
– The brain function test used cannot predict the mental advantages seen at four years or later as found positive in other clinical trials
– The wisdom of higher maternal (and infant) fish and DHA consumption is supported by other clinical evidence and by reams of mutually reinforcing cell, animal, and population research.
– Average American women and children do not get the recommended amounts of omega-3s.
– Higher maternal fish intake may be a better fetal brain-booster, compared with taking omega-3 fish oil supplements during pregnancy.
– Study did not compare whether infants were breast fed or formula
• Perhaps DHA in Milk is more important to improve cognition than in utero
JAMA. 2010;304(15):1675-1683
Recommendations: Infants & Children• The American Academy
of Pediatrics recommends that infant milk formula should provide at least 2.7% of total kilocalories in the form of linoleic acid.
• Of note, human milk provides 3.5% to as high as 12% of total kilocalories in the form of linoleic aciddepending on the fat composition of the maternal diet.
AI for Infants and Children0-6 mos 0.5 g/day of n-3 PUFA
7-12 mos 0.5 g/day of n-3 PUFA
1-3 yrs 0.7 g/day of a-linolenic acid
4-8 yrs 0.9 g/day of a -linolenic acid
Boys
9-13 yrs 1.2 g/day of a -linolenic acid
14-18 yrs 1.6 g/day o a-linolenic acid
Girls
9-13 yrs 1.0 g/day of a -linolenic acid
14-18 yrs 1.1 g/day of a -linolenic acid
Food and Nutrition Board, Institute of Medicine (FNBIOM,2001)
Recommendations During Pregnancy
• Eat up to 12 ounces of fish or shellfish (2 average meals) a week, including shrimp, canned light tuna, salmon, trout, catfish (found consistently low in mercury)
• Limit albacore tuna to 6 oz per week.
• Do not eat shark, swordfish, king mackerel, or tilefish because they contain high levels of mercury.
• If supplementing with fish oil capsule 100 to 200 mg EPA & DHA/day (most fish oil capsules are low in mercury and other harmful contaminants)
Oligosaccharides
• Quantitatively, oligosaccharides are the third largest solute in human milk after lactose (70g/l) and fat (40g/l). Mature milk contains over 15 g human milk oligosaccharides/l compared with only about 9 g protein/l
• Function has only recently been investigated.
• HMOs are
• Composed of both neutral and anionic species with building blocks of five monosaccharides: D-glucose, D-galactose, N-acetylglucos-amine, L-fucose, and N-acetylneuraminic acid
Oligosaccharides
• One of the most remarkable functions of breast milk
is to support the selective colonization and support of
a beneficial gut microflora.
• There are over 200 different human milk
oligosaccharide (HMO) structures that differ in their
size, charge, and sequence
• A direct mechanistic link has been demonstrated
between specific HMO structures and bifidobacterial
growth
Oligosaccharides – How do they Work?
• Various oligosaccharides in milk are believed to inhibit the binding of pathogenic bacteria and toxins, presumably by acting as decoys and binding to the bacterial surface, thus inhibiting their ability to bind to target oligosaccharides on the surface of epithelial cells
• Only Bifidobacterium and Bacteriodes species are able to consume HMOs as a sole carbon source and achieve high cell densities
• Bifidobacteria constitute >80% of the colonic microbiota in breast fed infants which are able to prevent or alleviate infectious diarrhoea through their effects on the immune system and resistance to colonization by pathogens
Conclusion: Breast is Best
http://www.heelpress.com/piece/image/1574/display/Breast_Feeding.jpg
Appendix:
Bioactive Factors in Human Milk
• Table 1. Multiple Functions of the Major Nutrients of Human Milk in the Infant• ______________________________________________________________________________________
____________________
• Nutrients Amount Function Protein mg/dL
• sIgA 50-100 Immune protection
• IgM 2 Immune protection
• IgG 1 Immune protection
• Lactoferrin 100-300 Anti-infective, iron carrier
• Lysozyme 5-25 Anti-infective
• α Lactalbumin 200-300 Ion carrier (Ca++), part of lactose synthase
• Casein 200-300 Ion carrier, inhibits microbial adhesion to mucosal membranes
• Carbohydrate g/L
• Lactose 6.5-7.3 Energy source
• Oligosaccharides 1.0-1.5 Microbial ligands
• Glycoconjugates Microbial and viral ligands
• Fat g/L
• Triglyceride 3.0-4.5 Energy source
• LC-PUFA* Essential for brain and retinal development and for infant growth
• FFA** Anti-infective
• __________________________________________________________________________________________________________
• * LC-PUFA: long chain polyunsaturated fatty acids
• ** FFA: free fatty acids, produced from triglycerides during fat digestion in the stomach and intestine
•BIOACTIVE FACTORS IN HUMAN MILK Margit Hamosh, Ph.D.
Professor of Pediatrics, Department of Pediatrics
Georgetown University Medical Center Washington, D.C. 20007-2197
Table 2. Protective Components in Human Milk__________________________________________________________________________________________________________
Immune protection Function
pIgA, IgG, M, D, E Specific antigen targeted anti-infective activity
Nonspecific protection Antibacterial, antiviral and antimicrobial-toxin enhancing newborn’s immune system maturation
Major nutrients (See Tables 1, 3 and 5)
Minor nutrients
Nucleotides Enhance: T cell maturation NK cell activity, antibody response to certain vaccines,
intestinal maturation and repair after diarrhea
Vitamins
A (b-carotene) anti-inflammatory (scavenging of oxygen radicals)
C (ascorbic acid) anti-inflammatory (scavenging of oxygen radicals)
E (α-tocopherol) anti-inflammatory (scavenging of oxygen radicals)
Enzymes
Bile salt dependent lipase production of FFA with antiprotozoan and antibacterial activity
Catalase anti-inflammatory (degrades H2O2)
Glutathione peroxidase anti-inflammatory (prevents lipid peroxidation)
PAF - acetylhydrolase protects against necrotizing enterocolitis (hydrolysis of PAF)
Hormones
Prolactin enhances the development of B and T lymphocytes, differentiation of intestinal
lymphoid tissue
Cortisol, thyroxine, promote maturation of the newborn’s intestine and insulin and growth factors development of
intestinal host-defense mechanism
Cells
Macrophages, PMNs Microbial phagocytosis, production of lymphokines and cytokines, interaction and enhancement with
other protective agents
Cytokines Modulate functions and maturation of the immune system
__________________________________________________________________________________________________________
PAF: platelet activating factor; PMN: polymorphonuclear
BIOACTIVE FACTORS IN HUMAN MILK Margit Hamosh, Ph.D.
Professor of Pediatrics, Department of Pediatrics
Georgetown University Medical Center Washington, D.C. 20007-2197
Table 3. Protective Function of Human Milk Protein______________________________________________________________________________
____________________________Protein Protective Function
Lactoferrin Iron chelation: bacteriostatic for siderophilic bacteria and fungi
(500-600 mg/dL Lactoferricin, 18 amino acid loop has broad spectrum
colostrum, 150 antimicrobial action
mg/dL in mature Antiviral activity (HIV, CMV, HSV) probably by interfering
with milk) the stage of virus adsorption and/or penetration
Immunomodulating activity: reduced release of IL-1, -2 and -6
and TFN-a from monocytes and of PgE2 from macrophages;
activation of NK cells, effect on complement activation and
coagulation Antiadhesive for E. coli and antiinvasive for S. flexneri
Antiadhesive for E. coli and antiinvasive for S. flexneri
Affects neonatal intestinal growth and recovery from injury,
thereby reducing intestinal infection
Lysozyme Bacterial lysis: hydrolysis of b1-4 link between N-acetyl-
5-25 mg/dL glucosamine and N-acetylmuramic acid in bacterial walls
increases with Immunomodulating activity: muramyl dipeptide enhances IgA prolonged lactation
production, macrophage activation
Binding to bacterial lipopolysaccharides: reduces endotoxic effect
k-casein Antiadhesive: Inhibits binding of H. pylori to human gastric
< 100 mg/dL mucosa and S. pneumoniae and H. influenzae to human respiratory
tract epithelial cells
Casein macropeptide is a strong growth promoting factor for B.
bifidum
____________________________________________________________________________________________________
______
HIV: human deficiency virus, CMV: cytomegalovirus, HSV: herpes symplex virus
BIOACTIVE FACTORS IN HUMAN MILK Margit Hamosh, Ph.D. Professor of Pediatrics, Department of Pediatrics
Georgetown University Medical Center Washington, D.C. 20007-2197
Table 4. Protective Functions of Oligoconjugates in Human Milk______________________________________________________________________________
____________________________
Structure Distribution in Milk Function
Oligosaccharides skim milk Protect against heat stable E. coli enterotoxin,
attachment of H. influenzae and S. pneumoniae
to respiratory epithelium, V. cholerae
hemagglutinin activity
Glycoproteins MFGM/skim milk Prevent binding of V. cholerae El Tor
Mucin MFGM Prevents binding of S. fimbriated E.
coli
Lactadherin MFGM/skim milk Prevents binding of Rotavirus
Gangliosides MFGM Receptor analogs for heat labile toxins of V.
cholerae and E. coli
Glycosaminoglycan MFGM Inhibits binding of HIV gp 120 to CD4
receptor
______________________________________________________________________________
____________________________
MFGM: milk fat globule membrane. Most of the listed activities are based on in vitro studies,
however, lactadherin prevents rotavirus-caused diarrhea in mice and human infants.
BIOACTIVE FACTORS IN HUMAN MILK Margit Hamosh, Ph.D. Professor of
Pediatrics, Department of Pediatrics
Georgetown University Medical Center Washington, D.C. 20007-2197
Table 5. Protective Functions of Human Milk Lipids______________________________________________________________________________
____________________________
Structural determinants FFA and MG. Most active: Lauric acid (C12:0) and
of anti-infective activity linoleic acid (C18:2).
Role of digestion Milk TG (98% of milk fat) have to be hydrolyzed in the
stomach* and intestine** to FFA and MG
Anti-infective function Antiprotozoan - Giardia lamblia
Antimicrobial - H. influenzae, group B Streptococci,
Staph. epidermidis
Antiviral - RSV, HSV-1
______________________________________________________________________________
____________________________
FFA: free fatty acid; MG: monoglyceride; TG: triglyceride; RSV: reticulo syncicial virus; HSV-1:
herpes simplex virus.
* Gastric lipolysis of milk TG higher in human milk-fed (25%) than formula-fed (14%) infants
(1); ** Human milk bile salt dependent lipase enhances intestinal fat digestion in breastfed
infants.
BIOACTIVE FACTORS IN HUMAN MILK Margit Hamosh, Ph.D. Professor of Pediatrics,
Department of Pediatrics Georgetown University Medical Center Washington, D.C. 20007-2197
Table 6. Immunomodulating Agents in Human Milk______________________________________________________________________________
Component Function Endogenous production by
infant
IL-1 Production of defense agents in
mammary gland
IL-3 markedly lower by T and
MN cells
IL-4 <10% of adult T cells
IL-5 reduced mRNA expression
IL-6 Regulates function of mammary gland normal in term, reduced in preterm
IL-8 Chemotactic for intestinal intraepithelial reduced mRNA and protein*
leukocytes
IL-10 Modulates epithelial barrier integrity 15-20% of adult level*
IL-12 Enhances production of inflammatory
cytokines ?
INF-g Modulates epithelial barrier integrity <10% of adult level
TNF-a Regulates function of mammary gland ~20-50% of adult level
TGF-b Anti-inflammatory
______________________________________________________________________________
____________________________
Cytokines IL-1b, IL-6, IL-8, INF-g and TNF-a are proinflamatory, whereas IL-10 and TGF-b are
anti-inflammatory
* After stimulation of mononuclear cells (IL-8), and Lps or TNF-a (IL-10).BIOACTIVE FACTORS IN HUMAN MILK Margit Hamosh, Ph.D. Professor of Pediatrics,
Department of Pediatrics Georgetown University Medical Center Washington, D.C. 20007-2197
Table 7. Antiinflammatory Components of Human Milk______________________________________________________________________________
Component Function
Vitamins A Scavenge oxygen radicals
C Scavenge oxygen radicals
E Scavenge oxygen radicals
Enzymes Catalase Degrades H2O2
Glutathione peroxidase Prevents lipid peroxidation
PAF*-acetylhydrolase Degrades PAF, a potent ulcerogen
Antienzymes a-1-antitrypsin inhibit inflammatory proteases
a-1-antichymotrypsin inhibit inflammatory proteases
Prostaglandins PGE1 cytoprotective
PGE2 cytoprotective
Growth factors EGF Promotes gut growth and functional
maturation
TGF-a Promotes epithelial cell growth
TGF-b Supresses lymphocyte function
Cytokines IL-10 Supresses function of macrophages, NK & T
cells
Cytokine receptors TGF-a - RI, RII Bind to and inhibit TGF-a
______________________________________________________________________________
_________________________________
*PAF: platelet activating factor.
Table 8. Enzymes with Digestive Function in the Infant______________________________________________________________________________
Characteristic Lipase (BSDL) Amylase
Maternal Factors
Parity (=10) ? Low activity
Diurnal and within feed activity Constant Constant
Secretion
Prepartum* Present ?
Postpartum Constant Decrease before
1st month
Preterm vs. term delivery** Equal activity Equal activity
Milk characteristics
Distribution Skim milk Skim milk
Storage (-20o,-70 o) Stable years Stable years
Storage (15-38 o) Stable (24 hrs) Stable (at least 24 hrs)
Stability to pH (stomach) >3.0 >3.0
pH optimum 7.4-8.5 6.5-7.5
Enzyme characteristics Identical to pancreatic CEL Isoenzyme of
salivary amylase
Evidence of activity in infants yes yes
Present in milk of other species Primates, carnivores,rodents ?
______________________________________________________________________________
__________________________________
BSDL: bile salt dependent lipase; CEL: cholesteryl ester lipase
* Prepartum - 2-3 months secretion; ** Infants delivered preterm (26-36 weeks gestation) and
term (37-40 weeks) gestation.
Table 9. Hormones in human milkHormone Concentration Milk:Plasma Mammary Effects newborn
/mL Ratio SynthesisPituitary
PRL 20-90ng >1.0 yes
Neuroendocrine
GH 5-30mU >1.0 ?
TSH 2.7-5.0mU <1.0 ? T3/T4
levels
Hypothalamus
TRH 0.025-1.5ng >1.0 no GH,
TSH
LHRH ? ? ? ?
Somatostatin 23-113pg >1.0 no ?
GnRH 0.1-4.0ng >1.0 yes ovarian
receptors
GHRH 23-430pg >1.0 ? GH
secretion
Thyroid
Thyroxine(T4) 0.3-12ng ? yes
Triiodothyronine 0.2-0.4ng ? yes
ReverseT3 (rT3 ) 0.008-0.15ng ? ?
Parathyroid
Parathormone(PTH) 15pg ? ?
PTH related peptide 30-50ng >1.0 yes
Calcitonin/CIP 0-5ng ? ?
Steroid
Estrogen 15-840 ng >1.0 yes
Progesterone 10-40 ng =1.0 no
Adrenal steroids 0.2-32ng <1.0 ? organ maturation
Table 10. Growth Factors in Human MilkGrowth Factor Concentration Milk:Plasma Mammary Effects in the newborn
/mL Ratio Synthesis
______________________________________________________________________________
EGF 3-107ng >1.0 yes GI growth and
gut closure
NGF ? ? ? ?
Insulin -20 mg >1.0 yes glycemia
IGF-I 1.3-11.0ng >1.0 yes stimulate
systemic growth
not epithelial
IGF-II ? >1.0 yes
TGF-α 0-8.4ng GI growth
Relaxin 0.3-0.5mg >1.0 ?
TGF-β ? ? ? inhibits GI growth
______________________________________________________________________________
Table 11. Erythropoetin, Melatonin and Leptin in Human Milk______________________________________________________________________________
Erythropoetin* Melatonin**
Leptin***
day night
Concentration in milk 11.7±0.75 <43 99 73
Concentration in mother’s serum 3.4-24.8 280 9-18
Concentration in infant’s serum 14.2±0.81 ? decrease pp#
Synthesis in mammary gland ? ? ?
Distribution in milk skim milk fat globules
Concentration throughout lactation < 2 months < ? ?
Absorption by newborn probable yes yes
Function in newborn ? awareness ?
______________________________________________________________________________
______________________________
*: mU/mL; **: fm/mL; ***: ng/mL; #: pp: post partum