Most recent update: June 2001 by Ginna Wall, MN, IBCLC, gwall@u.washington.edu

Originally compiled by: Jon Ahrendsen MD FAAFP

215 13th Ave. SW, Clarion, IA 50525; jonahr@netins.net


Table of Contents:

I. Effects on the Infant *

A. Infection *

1. Diarrhea *

2. Haemophilus Influenza *

3. Meningitis in Preterm Infants *

4. Necrotizing Enterocolitis *

5. Otitis Media (Middle Ear Infection) *

6. Pneumococcal Disease *

7. Respiratory Infections (general) *

8. Respiratory Syncytical Virus (RSV) *

9. Sepsis in Preterm Infants *

10. Urinary Tract Infections (UTI) *

B. Childhood Illnesses *

1. Autoimmune Thyroid Disease *

2. Cryptorchidism (Undescended Testicle) *

3. Gastroesophageal Reflex *

4. General Morbidity *

5. Immunologic Development *

6. Infant Survival *

7. Inguinal Hernia *

8. Pyloric Stenosis *

9. SIDS *

10. Toddler Health *

11. Wheezing *

C. Allergies *

1. Allergies in general *

2. Asthma *

3. Eczema *

D. Development and Intelligence *

1. Cognitive Development *

2. Gastrointestinal and Immune Development *

3. Hormones *

4. IQ *

5. Psychomotor and Social Development *

6. Thymus development *

7. Visual acuity *

E. Physiologic Response During Feedings *

F. Long Term Effects *

1. Appendicitis *

2. Bone mass *

3. Cancer *

4. Cardiovascular Disease, Cholesterol Concentration *

5. Celiac Disease *

6. Dental Health *

7. Diabetes Mellitus *

8. Helicobacter pylori infection *

9. Haemophilus Influenzae Meningitis *

10. Inflammatory Bowel Disease (Crohn's Disease, Ulcerative Colitis) *

11. Juvenile Rheumatoid Arthritis (JRA) *

12. Multiple Sclerosis *

13. Obesity *

14. Parent-child relationships *

15. Tonsillitis *

16. Transplant recipients *

17. Vaccine Response *


II. Maternal Effects *

A. Cancer *

1. Breast Cancer *

2. Endometrial Cancer *

3. Esophageal Cancer *

4. Ovarian Cancer *

5. Thyroid Cancer *

6. Uterine Cancer *

B. Emotional Health *

C. Fertility *

D. Insulin Requirements *

E. Osteoporosis *

F. Postpartum Weight Loss *

G. Urinary Tract Infections *


III. Societal Effects *

A. Child Abuse *

B. Child Spacing *

C. Environment *

D. Financial Cost to Government and Families *

1. Food Expense *

2. Medical Expenses *

E. Vaccine Effectiveness *


I. Effects on the Infant


A. Infection

1. Diarrhea


An episode of diarrhea was significantly less likely to last for six or more days if an infant was breastfed for three or more months. Baker D et al. "Inequality in infant morbidity: causes and consequences in England in the 1990s." J Epidemiol Community Health 1998 Jul;52(7):451-8

The risk of developing diarrhea increases as the amount of breast milk an infant receives decreases. When compared with exclusively breastfed infants, infants who were exclusively formula-fed had an 80% increase in their risk of developing diarrhea. Scariati PD et al. "A longitudinal analysis of infant morbidity and the extent of breastfeeding in the United States." Pediatrics 1997 Jun;99(6):E5

The type of milk consumed before start of diarrhea episode was strongly associated with dehydration. Compared with infants exclusively breastfed, bottle-fed infants were at higher risk (odds ratio for cow's milk = 6.0, for formula milk = 6.9). Compared with those still breastfeeding, children who stopped in the previous two months were more likely to develop dehydrating diarrhea. Fuchs SC et al. "Case-control study of risk of dehydrating diarrhoea in infants in vulnerable period after full weaning. BMJ 1996 Aug 17;313(7054):391-4

In the first year of life the incidence of diarrheal illness among breastfed infants was half that of formula-fed infants. Dewey KG et al. "Differences in morbidity between breast-fed and formula-fed infants." J Pediatr 1995 May;126(5 Pt 1):696-702

Children less than 12 months of age had a lower incidence of acute diarrheal disease during the months they were being breastfed than children that were fed with formula during the same period. Lerman,Y. et al. "Epidemiology of acute diarrheal diseases in children in a high standard of living settlement in Israel". Pediatr Infect Dis J 1994; 13(2);116-22.

Strictly formula-fed children had an incidence of diarrhea over three times that of strictly breast-fed infants and twice that of breast-fed and supplementally fed children. Long KZ et al. Proportional hazards analysis of diarrhea due to enterotoxigenic Escherichia coli and breastfeeding in a cohort of urban Mexican children. Am J Epidemiol. 1994 Jan 15;139(2):193-205.

In this study of 500 Brazilian infants < or = 12 months old with diarrhea and 500 age-matched controls, breast-feeding infants < 6 months old (OR, 0.3) and boiling household drinking water (OR, 0.4) were protective. Breast-feeding was protective against enteropathogenic Escherichia coli infections (OR, 0.1). Blake PA, et al. "Pathogen-specific risk factors and protective factors for acute diarrheal disease in urban Brazilian infants." J Infect Dis 1993 Mar;167(3):627-32

The addition to the breast-milk diet of even water, teas, and other nonnutritive liquids doubled or tripled the likelihood of diarrhea. Supplementation of breast-feeding with additional nutritive foods or liquids further increased significantly the risk of diarrhea. Popkin BM et al. "Breast-feeding and diarrheal morbidity." Pediatrics 1990 Dec;86(6):874-82

2. Haemophilus Influenza


The protective effects of human milk against otitis media may be due in part to inhibition of nasopharyngeal colonization with H. influenzae by specific secretory IgA antibody. Harabuchi Y et al. "Human milk secretory IgA antibody to nontypeable Haemophilus influenzae: possible protective effects against nasopharyngeal colonization. J Pediatr 1994 Feb;124(2):193-8

The adjusted odds ratio for exposure to breastfeeding was 0.5. Arnold C, et al. "Day care attendance and other risk factors for invasive Haemophilus influenzae type b disease." Am J Epidemiol 1993 Sep 1;138(5):333-40

Invasive Haemophilus influenzae type b (Hib) disease occurred at a mean age of 8.7 months. Breastfeeding was significantly less common among cases than controls (odds ratio = 0.53). Petersen GM. "Effects of age, breast feeding, and household structure on Haemophilus influenzae type b disease risk and antibody acquisition in Alaskan Eskimos. Am J Epidemiol 1991 Nov 15;134(10):1212-21

In a population-based case-control study of risk factors for primary invasion of haemophilus influenza, type B disease, breastfeeding was protective of infants less than 6 months of age. Cochi, S.L. "Primary Invasive Haemophilus Influenza Type B Disease, A Population Based Assessment of Risk Factors". Journal of Pediatrics 1986 Jun;108(6):887-96.

3. Meningitis in Preterm Infants


The incidence of any infection and sepsis/meningitis are significantly reduced in human milk-fed VLBW infants compared with exclusively formula-fed VLBW infants. Hylander MA et al. "Human milk feedings and infection among very low birth weight infants." Pediatrics 1998 Sep;102(3):E38

4. Necrotizing Enterocolitis


The benefits of improved health (less sepsis and necrotizing enterocolitis) associated with the feeding of fortified human milk outweighed the slower rate of growth observed in this study of 108 preterm infants. Infants fed human milk were discharged an average of 15 days earlier than infants preterm formula. Schanler RJ, et al. "Feeding strategies for premature infants: beneficial outcomes of feeding fortified human milk versus preterm formula." Pediatrics 1999 Jun;103(6 Pt 1):1150-7

Although no specific intervention for NEC treatment exists, preventive therapy using either enteral IgA supplementation, breast milk feeding, antibiotic prophylaxis, or exogenous steroid administration have reduced the incidence of this overwhelming disease in small randomized trials. Caplan MS, et al. "Necrotizing enterocolitis: a review of pathogenetic mechanisms and implications for prevention."(review) Pediatr Pathol 1993 May-Jun;13(3):357-69

Based on both laboratory and clinical studies, human milk feeding appears to have protective effects against development of necrotizing enterocolitis. Buescher ES. "Host defense mechanisms of human milk and their relations to enteric infections and necrotizing enterocolitis."(review) Clin Perinatol 1994 Jun;21(2):247-62

Among babies born at more than 30 weeks gestation, confirmed necrotizing enterocolitis was rare in those whose diet included breast milk; it was 20 times more common in those fed formula only. Lucas, A., Cole, T.J., "Breast Milk and Neonatal Necrotizing Enteral Colitis". Lancet 1990; 336:1519-23

5. Otitis Media (Middle Ear Infection)


The risk of developing an ear infection increases as the amount of breast milk an infant receives decreases. When compared with exclusively breastfed infants, infants who were exclusively formula-fed had a 70% increase in their risk of developing an ear infection. Scariati PD et al. "A longitudinal analysis of infant morbidity and the extent of breastfeeding in the United States." Pediatrics 1997 Jun;99(6):E5

In infants who were breast fed until at least 12 months of age, the percentage of any otitis media was 19% lower, and of prolonged episodes (> 10 days) was 80% lower than formula-fed infants. The mean duration of episodes of otitis media was longer in formula-fed than breastfed infants (8.8 vs 5.9 days, respectively). Dewey KG et al. "Differences in morbidity between breast-fed and formula-fed infants." J Pediatr 1995 May;126(5 Pt 1):696-702

Infants exclusively breast-fed for 4 or more months had half the number of acute otitis media episodes as did those not breastfed at all, and 40% less than those infants whose diets were supplemented with other foods prior to 4 months. The recurrent otitis media rate in infants exclusively breast-fed for 6 months or more was 10% and was 20.5% in those infants who breast-fed for less than 4 months. Duncan B et al. "Exclusive breast-feeding for at least 4 months protects against otitis media." Pediatrics 1993 May;91(5):867-72

Short duration of breastfeeding involved another significant risk of recurrent respiratory infections and otitis media. Alho, O., "Risk Factors for Recurrent Acute Otitis Media and Respiratory Infection in Infancy". INT J PED OTORHINOLARYNGOLOGY 1990; 19:151-61

Significantly increased risk for acute otitis media as well as prolonged duration of middle ear effusion were associated with male gender, sibling history of ear infection and not being breast fed. Teele, D.W., Epidemiology of Otitis Media During the First Seven Years of Life in Greater Boston: A prospective, Cohort Study". J of INFEC DIS.1989.


(See also: Duffy 1997, Aniansson 1994, Harabushi 1994, Paradise 1994, Sassen 1994, Owen 1993, Gulick 1986, Saarinen 1982)

6. Pneumococcal Disease


Among children 2 to 59 months, invasive pneumococcal disease was strongly associated with underlying disease and with day care attendance in the previous 3 months. Among 2- to 11-month-olds, current breastfeeding was associated with a decreased likelihood of invasive pneumococcal disease. Levine OS et al. "Risk factors for invasive pneumococcal disease in children: a population-based case-control study in North America." Pediatrics 1999 Mar;103(3):E28

7. Respiratory Infections (general)


Infants who were not being breast fed were 17 times more likely than those being breast fed exclusively to be admitted to hospital for pneumonia. Cesar JA et al. "Impact of breast feeding on admission for pneumonia during postneonatal period in Brazil: nested case-control study. BMJ 1999 May 15;318(7194):1316-1320

In a cohort of 1,202 healthy infants, born in Albuquerque, New Mexico, the daily occurrences of respiratory symptoms and breastfeeding status were reported by the mothers every 2 weeks during the first 6 months of life. After adjustment for potential confounding factors, full breastfeeding was associated with a reduction in lower respiratory illness risk (odds ratio=0.81) and significantly reduced the duration of respiratory illness. Cushing AH, et al. "Breastfeeding reduces risk of respiratory illness in infants." Am J Epidemiol 1998 May 1;147(9):863-70

Children who were not fed human milk had a 1.8-fold increased risk of respiratory disease at each level of exposure to passive cigarette smoke, in comparison with children who were fed human milk for at least 1 month. Jin C, Rossignol AM. "Effects of passive smoking on respiratory illness from birth to age eighteen months, in Shanghai, People's Republic of China. J Pediatr 1993 Oct;123(4):553-8

The authors presented results found in infants with two or more episodes of acute chronic bronchitis. They found that approximately twice as many bottle-fed infants presented with the problem as those who were breastfed. deDuran, C.M. "Cytologic Diagnosis of Milk Micro Aspiration". IMM ALLERGY PRACTICE 1991; xiii (10);402-5

Odds of respiratory illness with maternal smoking were 7 times higher among children who were never breastfed then among those who were breastfed. Woodward A et al. "Acute Respiratory Illness in Adelaide Children: BreastFeeding Modifies the Effect of Passive Smoking". J Epidemiol Community Health 1990 Sep;44(3):224-30

8. Respiratory Syncytical Virus (RSV)


Breastfeeding was associated with a lower incidence of RSV infection during the first year of life. Holberg,C.J., "Risk Factors for RSV Associated Lower Respiratory Illnesses in the First Year of Life". AM J Epidemiol 1991; 133 (135-51)

9. Sepsis in Preterm Infants


The incidence of any infection and sepsis/meningitis are significantly reduced in human milk-fed VLBW infants compared with exclusively formula-fed VLBW infants. Hylander MA et al. "Human milk feedings and infection among very low birth weight infants." Pediatrics 1998 Sep;102(3):E38

10. Urinary Tract Infections (UTI)


Breastfed infants have a relative risk of developing a UTI of 0.38 compared to formula-fed infants. Pisacane A et al. "Breast-feeding and urinary tract infection." J Pediatr 1992 Jan;120(1):87-9

The oligosaccharide content of breast-milk and urine from nursing mothers is very similar, and the pattern of oligosaccharides excreted by infants is also strongly correlated with that of breastmilk. The oligosaccharides cause inhibition of bacterial adhesion, suggesting that breastfeeding may have a preventive effect on urinary tract infection in both mother and infant. Coppa GV et al. "Preliminary study of breastfeeding and bacterial adhesion to uroepithelial cells." Lancet 1990 Mar 10;335(8689):569-71


B. Childhood Illnesses

1. Autoimmune Thyroid Disease


Feeding practices in infancy may affect the development of various autoimmune diseases later in life. Thyroid alterations are among the most frequently encountered autoimmune conditions in children. A detailed history of feeding practices was obtained in 59 children with autoimmune thyroid disease, their 76 healthy siblings, and 54 healthy nonrelated control children. The frequency of feedings with soy-based milk formulas in early life was significantly higher in children with autoimmune thyroid disease (prevalence 31%) as compared with their siblings (prevalence 12%), and healthy nonrelated control children (prevalence 13%). Fort P, et al. Breast and soy-formula feedings in early infancy and the prevalence of autoimmune thyroid disease in children. J Am Coll Nutr. 1990 Apr;9(2):164-7.

2. Cryptorchidism (Undescended Testicle)


This case-controlled study showed a significant association of cryptorchidism and lack of breastfeeding. Mori, M. "Maternal and other factors of cryptorchidism: a case-control study in Japan" Kurume Med J, 1992:39:53-60

3. Gastroesophageal Reflex


Breastfed neonates demonstrate gastroesophageal reflux episodes of significantly shorter duration than formula fed neonates. Heacock, H.J., "Influence of Breast vs. Formula Milk in Physiologic Gastroesophageal Reflux in Health Newborn Infants". J. Pediatr Gastroenterol Nutr, 1992 January; 14(1): 41-6

4. General Morbidity


The association between breastfeeding dose and illnesses in the first 6 months of life was analyzed for 7092 infants. Breastfeeding dose (ratio of breast-feedings to other feedings) was categorized as "full," "most," "equal," "less," or "no" breastfeeding. Compared with no breastfeeding, full breast-feeding infants had lower odds ratios of diarrhea, cough or wheeze, and vomiting and lower mean ratios of illness months and sick baby medical visits. "Most" breastfeeding infants had lower odds ratios of diarrhea and cough or wheeze, and "equal" breast-feeding infants had lower odds ratios of cough or wheeze. "Full," "most," and "equal" breastfeeding infants without siblings had lower odds ratios of ear infections and certain other illnesses, but those with siblings did not. "Less" breastfeeding infants had no reduced odds ratios of illness. Findings did not vary by income. Raisler J et al. "Breast-feeding and infant illness: a dose-response relationship? J Public Health 1999 Jan;89(1):25-30

The incidence of any infection and sepsis/meningitis are significantly reduced in human milk-fed VLBW infants compared with exclusively formula-fed VLBW infants. Hylander MA et al. "Human milk feedings and infection among very low birth weight infants." Pediatrics 1998 Sep;102(3):E38

During the first 6 months of life, breastfeeding has a protective effect of against respiratory illnesses, gastrointestinal illnesses, and on all illnesses. Beaudry M et al. "Relation between infant feeding and infections during the first six months of life." J Pediatr 1995 Feb;126(2):191-7

Jones EG et al. "Relationship between infant feeding and exclusion rate from child care because of illness." J Am Diet Assoc 1993 Jul;93(7):809-11

There is an inverse relationship to breastfeeding and morbidity. This was most prominent in the first year of life, but it was also present in the first three years. Van Den Bogaard, C. "Relationship Between Breast Feeding in Early Childhood and Morbidity in a General Population". Fan Med, 1991; 23:510-515

5. Immunologic Development


Review article: Protection against infections has been well evidenced during lactation against, e.g., acute and prolonged diarrhea, respiratory tract infections, otitis media, urinary tract infection, neonatal septicemia, and necrotizing enterocolitis. There is also interesting evidence for an enhanced protection remaining for years after lactation against diarrhea, respiratory tract infections, otitis media, Haemophilus influenzae type b infections, and wheezing illness. In several instances the protection seems to improve with the duration of breastfeeding. A few factors in milk like anti-antibodies (anti-idiotypic antibodies) and T and B lymphocytes have in some experimental models been able to transfer priming of the breastfed offspring. This together with transfer of numerous cytokines and growth factors via milk may add to an active stimulation of the infant's immune system. Such an enhanced function could also explain why breastfeeding may protect against immunologic diseases like celiac disease and possibly allergy. Suggestions of protection against autoimmune diseases and tumors have also been published. Hanson LA. "Breastfeeding provides passive and likely long-lasting active immunity. Ann Allergy Asthma Immunol 1998 Dec;81(6):523-33; quiz 533-4, 537

Secretory IgA concentration increased more rapidly during the first 6 months after birth in infants exclusively breastfed than in those exclusively bottle fed. Fitzsimmons SP, et al. "Immunoglobulin A subclasses in infants' saliva and in saliva and milk from their mothers." J Pediatr 1994 Apr;124(4):566-73

Enhanced fecal SIgA in breastfed infants is not caused solely by the presence of IgA in breast milk; it represents a stimulatory effect of breast milk on the gastrointestinal humoral immunologic development. Koutras, A.K., "Fecal Secretory Immunoglobulin A in Breast Milk vs. Formula Feeding in Early Infancy". J Ped Gastro Nutr, 1989.

6. Infant Survival


There is association between breastfeeding up to 6 months of age and survival of infants throughout the first year of life. The younger the infant and the longer the breastfeeding, the greater the estimated benefits in terms of death averted. Habicht, J.P., "Does Breast Feeding Really Save Lives, or Are Apparent Benefits due to Biases?" Am J Epidemiology, 1986

7. Inguinal Hernia


Human milk contains gonadotropin releasing hormone, which may affect the maturation of neonatal testicular function. This case-control study showed breastfed infants had a significant dose response reduction in inguinal hernia. Pisacane, A. "Breast-feeding and inguinal hernia" Journal of Pediatrics 1995:Vol 127, No. 1, pp 109-111

8. Pyloric Stenosis


Infants with pyloric stenosis were less likely to have been breastfed during the first week of life. Pisacane A, et al. Breast feeding and hypertrophic pyloric stenosis: population based case-control study. BMJ. 1996 Mar 23;312(7033):745-6.



Sixty-three infants who died suddenly and unexpectedly were classified into 3 groups: SIDS (19 cases), borderline SIDS (30 cases) and non-SIDS (14 cases). Non-SIDS cases received more breastfeeding, the parents hardly smoked during pregnancy and after birth, a firm mattress had been used, and more often signs of illness had been reported by the parents, compared with the SIDS and borderline SIDS cases. L'Hoir MP et al. "Sudden unexpected death in infancy: epidemiologically determined risk factors related to pathological classification." Acta Paediatr 1998 Dec;87(12):1279-87

Not breastfeeding at discharge from an obstetric hospital at any stage of the infant's life was associated with an increased risk of SIDS. Mitchell, A. "Results from the First Year of The New Zealand Count Death Study". N.Z. Med A, 1991; 104:71-76

A study indicated that breastfeeding was protective against SIDS, consistent with an effect mediated through the prevention of gastrointestinal and/or respiratory disease. Hoffman, H.J., "Risk Factors for SIDS: Results of the National Institute of Child Health and Human Development SIDS Cooperative Epidemiologic Study". Ann NY ACAD Sci, 1988.

10. Toddler Health


Mothers of 67 infants were questioned about the types and duration of illness episodes requiring medical care between 16 and 30 months of age. Breastfeeding was noted to decrease the number of infant illnesses and indirectly improve toddler health. Gulick, E.E. "The Effects of Breastfeeding on the Toddler Health." Pediatric Nursing, 1986 Jan-Feb;12(1):51-4.

11. Wheezing


Infants who were breastfed for three or more months were significantly less likely to have three or more episodes of wheezing in the first six months after birth. Baker D et al. "Inequality in infant morbidity: causes and consequences in England in the 1990s." J Epidemiol Community Health 1998 Jul;52(7):451-8

Children who had ever been breast fed had a lower incidence of wheeze than those who had not (59% and 74% respectively). The effect persisted to age 7 years in the non-atopics only, the risk of wheeze being halved in the breast fed children. Burr ML, et al. "Infant feeding, wheezing, and allergy: a prospective study." Arch Dis Child 1993 Jun;68(6):724-8

Within the group who had had early wheezing, infants who had been breastfed for at least one month subsequently had less severe wheezing. Porro E, et al. "Early wheezing and breast feeding." J Asthma 1993;30(1):23-8

Breastfeeding seems to protect against wheezing respiratory tract illnesses in the first 4 months of life, particularly when other risk factors are present. Wright, A.L., "Breastfeeding and lower respiratory Tract Illnesses in the First Year of Life". British Medical Journal, 1989.


C. Allergies

1. Allergies in general


2187 children were followed to age 6 years to study the association between duration of exclusive breast feeding and asthma or atopy. After adjustment for confounders, the introduction of milk other than breastmilk before 4 months of age was a significant risk factor for all asthma and atopy related outcomes in children aged 6 years. A significant reduction in the risk of childhood asthma at age 6 years occurs if exclusive breast feeding is continued for at least the 4 months after birth.

Oddy WH et al. "Association between breast feeding and asthma in 6 year old children: findings of a prospective birth cohort study." BMJ 1999 Sep 25;319(7213):815-9

A birth cohort was followed-up to age 4 years. By age 4 years, 27% of the children had symptoms of allergic disease. Family history of atopy was the single most important risk factor for atopy in children. Sibling atopy was a stronger predictor of clinical disease than maternal or paternal atopy. Formula-feeding before 3 months of age predisposed to asthma at age 4 years (OR: 1.8). Tariq SM, et al. The prevalence of and risk factors for atopy in early childhood: a whole population birth cohort study. J Allergy Clin Immunol. 1998 May;101(5):587-93.

The factors most important in the pathogenesis of allergic symptoms were: (i) formula implementation begun in the first week of life; (ii) early weaning (< 4 months); (iii) feeding beef (< 6 months); (iv) early introduction of cow's milk (< 6 months); and (v) parental smoking in the presence of the babies and early day care admission (< 2 years of life). All the preventive measures used in this study (exclusive breastfeeding and/or hydrolyzed milk feeding, delayed and selective introduction of solid foods, and environmental advice) were effective at the third year of follow-up, greatly reducing allergic manifestations in high atopic risk babies in comparison with those not receiving these interventions Marini A et al. "Effects of a dietary and environmental prevention programme on the incidence of allergic symptoms in high atopic risk infants: three years' follow-up. Acta Paediatr Suppl 1996 May;414:1-21

Breastfeeding, even for short periods was clearly associated with lower incidence of wheezing, prolonged colds, diarrhea, and vomiting. Merrett, T.G., "Infant Feeding & Allergy: 12 Month Prospective Study of 500 Babies Born into Allergic Families". American Allergies, 1988.

2. Asthma


Introducing milk other than breast milk to infants younger than 4 months old increases the risk of asthma and atopy (a predisposition to certain allergies). The investigators followed 2,187 children from before birth through their 6th birthday. Children who were fed milk other than breast milk before 4 months of age experienced higher rates of all indicators of asthma and allergy. Such children were 25% more likely to be diagnosed with allergy and 30% more likely to have a positive skin test for allergies than were children who received only breast milk during their early months. The total duration of exclusive breastfeeding was less important, though longer breastfeeding was associated with less asthma and allergy. The researchers also found increased risks of asthma and atopy among boys, infants born prematurely, and children living in households where smoking took place. Oddy W et al. British Medical Journal Sep 1999;319:815-819.

3. Eczema


Prospective randomized double-blind study of high-risk infants with a family history of atopy followed until 5 years of age showed a significant lowering in the incidence of atopic disease in the breast-fed and the whey hydrolysate groups, compared with the conventional cow's milk group. Soy formula was not effective. The occurrence of both eczema and asthma was lowest in the breast-fed and whey hydrolysate groups and was comparable in the cow's milk and soy groups. Chandra RK. "Five-year follow-up of high-risk infants with family history of allergy who were exclusively breast-fed or fed partial whey hydrolysate, soy, and conventional cow's milk formulas." J Pediatr Gastroenterol Nutr 1997 Apr; 24(4):380-8

Eczema was less common and milder in babies who were breast fed (22%) and whose mothers were on a restricted diet (48%). In infants fed casein hydrolysate, soymilk or cows milk, 21%, 63%, and 70% respectively, developed atopic eczema. Chandra R.K., "Influence of Maternal Diet During Lactation and the Use of Formula Feed and Development of Atopic Eczema in the High Risk Infants". Br Med J. 1989


D. Development and Intelligence

1. Cognitive Development


96 healthy term infants, aged between 10 and 14 months were assessed using the Bayley Scales of Infant Development. Duration of breast-feeding significantly predicted mental development scores for boys, but not for girls. Duration of breast-feeding did not predict psychomotor development scores. Paine BJ, Makrides M, Gibson RA. "Duration of breast-feeding and Bayley's Mental Developmental Index at 1 year of age." J Paediatr Child Health 1999 Feb;35(1):82-5.

Increasing duration of breastfeeding was associated with consistent and statistically significant increases in 1) intelligence quotient assessed at ages 8 and 9 years; 2) reading comprehension, mathematical ability, and scholastic ability assessed during the period from 10 to 13 years; 3) teacher ratings of reading and mathematics assessed at 8 and 12 years; and 4) higher levels of attainment in school leaving examinations. Breastfeeding is associated with small but detectable increases in child cognitive ability and educational achievement. These effects are 1) pervasive, being reflected in a range of measures including standardized tests, teacher ratings, and academic outcomes in high school; and 2) relatively long-lived, extending throughout childhood into young adulthood. . Horwood LJ, Fergusson DM. "Breastfeeding and later cognitive and academic outcomes." Pediatrics 1998 Jan;101(1):E9

Supplementary regression analysis examining the strength of relationship between duration of breastfeeding and cognitive development show small but significant relationship between duration of breastfeeding and scores on the mental development index of the Bayley Scales at 1 and 2 years. Morrow-Tlucak, M. "Breast Feeding and Cognitive Development During the First 2 years of Life. "Soc Sci Med, 1988, 26(6):635-9.

In 771 low birth weight infants, babies whose mothers chose to provide breast milk had an 8 point advantage in mean Bayley's mental developmental index over infants of mother choosing not to do so. Morley, R., "Mothers Choice to provide Breast Milk and Developmental Outcome". Arch Dis Child, 1988

2. Gastrointestinal and Immune Development


This article summarizes the published data on the intestinal microflora in breastfed infants published during the last 15 y. Acetic acid is found in higher concentrations in breastfed than in formula-fed infants. Degradation of mucin starts later in breastfed than in formula-fed infants. The conversion of cholesterol to coprostanol is also delayed by breastfeeding. Orrhage K and Nord CE. "Factors controlling the bacterial colonization of the intestine in breastfed infants." Acta Paediatr Suppl 1999 Aug;88(430):47-57

Nucleotides (NT) and their related metabolic products play key roles in many biological processes. Most dietary NT are rapidly metabolized and excreted. However, some are incorporated into tissues, particularly at younger ages. Under conditions of limited NT intake, rapid growth or certain disease states, dietary NT may spare the cost of de novo NT synthesis and optimize the function of rapidly dividing tissues such as those of the gastrointestinal and immune systems. Animals fed NT-supplemented versus non-NT supplemented diets have enhanced gastrointestinal growth and maturation, and improved recovery following small and large bowel injury. Indices of humoral and cellular immunity are enhanced, and survival rates are higher following infection with pathogens. Infants receive NT in human milk, where they are present as nucleic acids, nucleosides, nucleotides and related metabolic products. The NT content of human milk is significantly higher than most cow's milk-based infant formulae. Dietary NT are reported to enhance the gastrointestinal and immune systems of formula-fed infants. Infants fed NT-supplemented versus non-supplemented formula have a lower incidence of diarrhea, higher antibody titers following Haemophilus influenzae type b vaccination and higher natural killer cell activity. These data suggest that human milk NT may contribute to the superior clinical performance of the breastfed infant. Carver JD. "Dietary nucleotides: effects on the immune and gastrointestinal systems." Acta Paediatr Suppl 1999 Aug;88(430):83-8

3. Hormones


Hormones, growth factors, cytokines and even whole cells are present in breast milk and act to establish biochemical and immunological communication between mother and child. In addition, milk nutrients such as nucleotides, glutamine and lactoferrin have been shown to influence gastrointestinal development and host defense. Bernt KM and Walker WA. "Human milk as a carrier of biochemical messages." Acta Paediatr Suppl 1999 Aug;88(430):27-41.

Human milk as well as the milk of several mammalian species contains a group of biologically active substances that directly influence the newborn's metabolism and promote growth and differentiation of organs and target tissues. The biological significance of hormones and growth factors in milk is an area of active research. Murphy MS. "Growth factors and the gastrointestinal tract." Nutrition 1998 Oct;14(10):771-4

Erythropoietin stimulates production of red blood cells and is used in the treatment of anemia of prematurity. Human milk contains considerable amounts of erythropoietin which resist degradation after exposure to gastric juices at physiologic pH levels. Kling PJ et al. "Human milk as a potential enteral source of erythropoietin." Pediatr Res 1998 Feb;43(2):216-21

Prolactin may be important for lung maturation and surfactant synthesis, and may play a role in the growth of the gut and intestinal absorption of fluid and ions. In a study of 280 infants weighing less that 1850 grams at birth, higher plasma prolactin levels were associated with fewer days on ventilator, faster transition to full enteral feedings, and greater gain in length. Lucas A et al. "Plasma prolactin and clinical outcome in preterm infants." Archives of Disease in Childhood, 1990, 65:977-983.

4. IQ


A review of 20 published studies on the effects of breastfeeding on infant IQ found that breastfed babies' IQs may be 3 to 5 points higher than those of formula-fed babies. The longer a baby is breast-fed, the greater the benefits to his or her IQ. These benefits were seen from age 6 months through 15 years. Anderson JW et al. American Journal of Clinical Nutrition, Oct 1999, 70.

School-age phenylketonuric children who had, as infants, been breastfed 20-40 days prior to dietary intervention scored significantly better (IQ advantage of 14.0 points, p = 0.01) than children who had been formula fed. A 12.9 point advantage persisted also after adjusting for social and maternal education status. Riva E et al. "Early breastfeeding is linked to higher intelligence quotient scores in dietary treated phenylketonuric children. Acta Paediatr 1996 Jan;85(1):56-8

Children who had consumed mother's milk by tube in early weeks of life had a significantly higher IQ at 7.5 to 8 years, than those who received no maternal milk, even after adjustment for differences between groups and mothers' educational and social class. Lucas, A., "Breast Milk and Subsequent Intelligence Quotient in Children Born Preterm". Lancet 1992;339:261-62

5. Psychomotor and Social Development


Infants were exclusively breastfed for 4 months and then randomly assigned to continue exclusive breastfeeding until 6 months or to receive high-quality, hygienic solid foods in addition to breast milk between 4 and 6 months. Infants who were exclusively breastfed for 6 months crawled sooner and were more likely to be walking by 12 mo than infants who started solid foods at 4 months. Dewey KG et al. Effects of exclusive breastfeeding for four versus six months on maternal nutritional status and infant motor development: results of two randomized trials in Honduras. J Nutr 2001 Feb;131(2):262-7

The associations of breastfeeding duration and milk fat composition with the developmental outcome at l year of age were measured in 44 infants exclusively breastfed for 3 months, out of 95 recruited at birth. Pooled breast milk (hindmilk) of the mothers was analysed at colostrum, 1, 3, 6, 9, and 12 months for total fat and fatty acid content. Infants were examined at 12 months by means of the Bayley test. There was a progressive reduction of the number of breastfed babies after the introduction of solids to 29 (6 months), 17 (9 months) and 10 (12 months). After adjusting for major confounders, infants breastfed for 6 months or longer showed a trend to have an advantage at the Bayley psychomotor developmental index compared to those breastfed >3 and <6 months while the Bayley mental developmental index (MDI) was just 2.1 points higher. Among the milk fat components considered for each time-point, the total fat content at 6 months showed the strongest association with the MDI at 12 months (r=0.59, P=0.001). Prolonging breastfeeding during the weaning process may result in a better developmental performance at 12 months, possibly due to the supply of fats affecting brain composition. Agostoni C. "Breastfeeding duration, milk fat composition and developmental indices at 1 year of life among breastfed infants." Prostaglandins Leukotrienes and Essential Fatty Acids. Feb 2001; 64 (2) : 105-109.

Infants (4 to 6 months old) looked at a mobile significantly longer when tested after breastfeeding. This finding suggests that breastfeeding has a substantial effect on infants' attentiveness to and interaction with their environment. Gerrish CJ and Mennella JA. "Short-term influence of breastfeeding on the infants' interaction with the environment. Dev Psychobiol 2000 Jan;36(1):40-48.

Motor skills and early language development were evaluated in 1656 8-month-olds. The proportion of infants who mastered the specific milestones increased consistently with increasing duration of breastfeeding. The relative risk for the highest versus the lowest breastfeeding category was 1.3 for crawling, 1.2 for pincer grip and 1.5 for polysyllable babbling. Little change was found after adjustment for confounding factors. In conclusion, data support the hypothesis that breastfeeding benefits neurodevelopment. Vestergaard M et al. Duration of breastfeeding and developmental milestones during the latter half of infancy. Acta Paediatr 1999 Dec;88(12):1327-32

Children breastfed for 9 months or more present significantly less suspected developmental delay (25.5%, measured by the Denver II test) than those breast fed for less than 1 month (42.4%). Barros FC. "Breast feeding, pacifier use and infant development at 12 months of age: a birth cohort study in Brazil." Paediatr Perinat Epidemiol 1997 Oct;11(4):441-50

A prospective study of measured psychomotor development between 18 and 29 months using the Bayley scales. Lower results on the Index of Mental Development were associated with bottle-fed infants. Temboury MC et al. "Influence of breast-feeding on the infant's intellectual development." J Pediatr Gastroenterol Nutr 1994 Jan;18(1):32-6

The psychomotor and social development of breastfed babies clearly differs from that of bottle-fed ones and leads at the age of 12 months to significant advantages of the psychomotor and social capabilities. Baumgartner, C., "Psychomotor and Social Development of Breast Fed and Bottle Fed babies During their First year of Life". Acta Paediatrica Hungarica, 1984 25(4):409-17.

6. Thymus development


At 10 months the thymic index was significantly higher in those still being breast-fed compared to infants who had stopped breast-feeding between 8 and 10 months of age. In infants still breast-fed at 10 months there was a significant correlation between the number of breast-feeds per day and their thymic index. Hasselbalch H et al, "Breast-feeding influences thymic size in late infancy." Eur J Pediatr 1999 Dec;158(12):964-7

Forty-seven healthy infants were examined as neonates and re-examined at 4 months of age. Thirty-seven of the infants were also re-examined at 8, 10, and 12 months of age. The thymus size was measured. Infants exclusively breast-fed during the first 4 months of their lives had a larger thymic index at 10 months than formula-fed infants. Infants with fever episodes from 10 to 12 months had a smaller thymic index at 12 months. The thymus size in healthy infants increases from birth to 4 and 8 months of age and then decreases. Hasselbalch H et al. Thymus size evaluated by sonography. A longitudinal study on infants during the first year of life. Acta Radiol 1997 Mar;38(2):222-7

At 4 months the geometric mean thymic index was 38.3 in exclusively breastfed infants (n = 21), 27.3 in partially breastfed infants (n = 13) and 18.3 in formula fed infants (n = 13). This finding was independent of weight, length, sex and previous or current illness. There was no significant difference in mean thymic index at birth between the three feeding groups and mean thymic index had increased in all three groups from birth to 4 months. Conclusion: the thymus is considerably larger in breastfed than in formula-fed infants at the age of 4 months. The cause of this difference is unknown but human milk contains many immune modulating factors that might cause this effect. Hasselbalch H et al. Decreased thymus size in formula-fed infants compared with breastfed infants. Acta Paediatr 1996 Sep;85(9):1029-32

7. Visual acuity


Observational studies suggested that breastfeeding benefits the visual development of preterm children, which has been attributed to the presence of docosahexaenoic acid (DHA) in breast milk but not most formula milks. Randomized studies showed that preterm children require a dietary supply of DHA in the first few weeks of life fur optimal visual development, but it is unclear whether full-term children experience similar benefits from breast milk or DHA supplements. The objective of this study was to compare stereoacuity at age 3.5 years in healthy, full-term children who were breast-fed and in similar children who had not been breast-fed after adjustment fur socioeconomic status and maternal diet. Prospectively collected data on maternal diet during pregnancy (including intake of oily fish), the child's diet, and the socioeconomic status of the family were examined. Children who had been breast-fed for 4 mo were more likely to achieve high-grade stereopsis, or stereoscopic vision, than were children who had not been breast-fed (adjusted odds ratio: 2.77). The mother's antenatal blood DHA content was associated with her intake of oily fish (P < 0.0001). Children whose mothers ate oily fish during pregnancy were also more likely to achieve high-grade stereopsis than were children whose mothers did not eat oily fish (adjusted odds

ratio: 1.57). The results of this study suggest that for full-term infants, breast-feeding is associated with enhanced stereopsis at age 3.5 years, as is a maternal DHA-rich antenatal diet, irrespective of later infant feeding practice. Williams C, et al. Stereoacuity at age 3.5 y in children born full-term is associated with prenatal and postnatal dietary factors: a report from a population-based cohort study. American-Journal-Of-Clinical-Nutrition. Feb 2001; 73 (2) : 316-322


E. Physiologic Response During Feedings

Preterm infants demonstrated a higher oxygen saturation and a higher temperature during breastfeeding than during bottle feeding, and were less likely to desaturate to <90% oxygen during breastfeeding. Blaymore Bier JA et al. "Breastfeeding infants who were extremely low birth weight. Pediatrics 1997 Dec;100(6):E3

In infants with congenital heart disease, oxygen saturations during breastfeeding were higher on average and less variable than during bottle feedings, indicating that there is less cardiorespiratory stress with breastfeeding. Marino BL et al. "Oxygen saturations during breast and bottle feedings in infants with congenital heart disease." J Pediatr Nurs 1995 Dec;10(6):360-4

Supine bottle feeding has a significant effect on middle-ear pressure dynamics, probably caused by the aspiration of milk into the ear. Tully SB et al. "Abnormal tympanography after supine bottle feeding." J Pediatr 1995 Jun;126(6):S105-11


F. Long Term Effects

1. Appendicitis


Pisacane A, et al. Breast feeding and acute appendicitis. BMJ. 1995 Apr 1;310(6983):836-7.

2. Bone mass


In this study of 330 8-year-old children from Southern Tasmania, those who were breastfed had higher bone mineral density at the femoral neck, lumbar spine and total body compared with those who were bottle-fed. This association remained significant after adjustment for size, lifestyle factors and socioeconomic factors. Breastfeeding for less than 3 months was not associated with increased bone mass at any site. Jones G, Riley M, Dwyer T. Breastfeeding in early life and bone mass in prepubertal children: a longitudinal study. Osteoporos Int 2000;11(2):146-52

3. Cancer

a) Breast Cancer in Adulthood


Having been breastfed as an infant has been associated with a 20-35% reduction in risk of premenopausal breast cancer in four of six studies evaluating this factor. Potischman-N; Troisi-R. "In-utero and early life exposures in relation to risk of breast cancer." Cancer-Causes-And-Control. 1999; 10 (6): 561-573

Women who were breastfed as infants, even if only for a short time, showed an approximate 25% lower risk of developing premenopausal or postmenopausal breast cancer, compared to women who were bottle-fed as an infant. Freudenheim, J. "Exposure to breast milk in infancy and the risk of breast cancer." Epidemiology 1994 5:324-331

b) Childhood Cancer


In a case-controlled study of 593 cases of cancer in Moscow children 0 to 14 years of age, the positive trend of increased risk of cancer with decreasing duration of breastfeeding was significant for all cancer combined. Smulevich VB, Solionova LG, Belyakova SV. "Parental occupation and other factors and cancer risk in children: I. Study methodology and non-occupational factors." Int J Cancer 1999 Dec 10;83(6):712-7.

Children who are artificially fed or breastfed for only 6 months or less, are at an increased risk of developing cancer before age 15. The risk of artificially-fed children was 1-8 times that of long-term breastfed children, and the risk for short term feeders was 1-9 times that of long term breast feeders. Davis, M.K. "Infant Feeding and Childhood Cancer." Lancet 1988 13;2(8607):365-8.

c) Hodgkin's Disease


This review of 9 published case-control studies suggests that children who are never breast-fed or are breast-fed short-term have a higher risk than those breast-fed for > 6 months of developing Hodgkin's disease, but not non-Hodgkin's lymphoma or acute lymphoblastic leukemia. Davis MK. "Review of the evidence for an association between infant feeding and childhood cancer." Int J Cancer Suppl 1998;11:29-33

A statistically significant protective effect against Hodgkin's disease among children who are breastfed at least 8 months compared with children who were breastfed no more than 2 months. Schwartzbaum, J. "An Exploratory Study of Environmental and Medical Factors Potentially Related to Childhood Cancer." Medical & Pediatric Oncology, 1991; 19 (2):115-21.

d) Leukemia and Lymphoma


This case-controlled study of 117 Bedouin Arab children showed that breastfeeding for less than six months was associated with an odds ratio of 2.79 for contracting a lymphoid malignancy compared with children breastfed longer than six months. European Journal of Cancer2001 January;37:234-238.

A total of 1744 children with acute lymphoblastic leukemia (ALL) and 1879 matched control subjects, aged 1-14 years, and 456 children with acute myeloid leukemia (AML) and 539 matched control subjects, aged 1-17 years, were studied. Ever having breast-fed was found to be associated with a 21% reduction in risk of childhood acute leukemias. The inverse associations were stronger with longer duration of breast-feeding. Shu XO etal, "Breast-feeding and risk of childhood acute leukemia. J Natl Cancer Inst 1999 Oct 20;91(20):1765-72

In interviews with the mothers of 2,200 children affected by either acute lymphoblastic leukemia (ALL) or acute myeloid leukemia (AML), the infant-feeding history of each of these children was compared with that of over 2,400 healthy controls. The investigators found that a history of breastfeeding was associated with a reduction in risk of childhood acute leukemias. Babies who are breast-fed for as little as one month have a 20% lower risk of childhood leukemia than bottle-fed babies, and babies breast-fed for more than 6 months have an even lower risk -- 30% less. Robison L et al. Journal of the National Cancer Institute 1999;91:1765-1772.

4. Cardiovascular Disease, Cholesterol Concentration


Breastfeeding has been associated with lower blood pressure in later life, but previous studies have not controlled for possible confounding factors by using a randomized design with prospective follow-up. In this study, blood pressure was measured at age 13-16 years in 216 (23%) of a cohort of 926 children who were born prematurely and had participated at birth in two parallel randomised trials in five neonatal units in the UK. Dietary interventions were: donated banked breastmilk versus preterm formula and standard term formula versus preterm formula. Children followed up at age 13-16 years were similar to those not followed up in terms of social class and anthropometry at birth. Mean arterial blood pressure at age 13-16 years was lower in the 66 children assigned banked breastmilk (alone or in addition to mother's milk) than in the 64 assigned preterm formula (mean 81.9 vs 86.1 mm Hg; p=0.001). In non-randomised analyses, the proportion of enteral intake as human milk in the neonatal period was inversely related to later mean arterial pressure. No differences were found in the term formula (n=44) versus preterm formula (n=42) comparison. Breastmilk consumption was associated with lower later blood pressure in children born prematurely. This data provide experimental evidence of programming of a cardiovascular risk factor by early diet and further support the long-term beneficial effects of breastmilk. Singhal A, Cole TJ, Lucas A. "Early nutrition in preterm infants and later blood pressure: two cohorts after

randomised trials." Lancet 2001 Feb 10;357(9254):413-9

Exclusive breast feeding seems to have a protective effect against some risk factors for cardiovascular disease in later life. In this study of 625 adults aged 48-53 years, those who were bottle fed had a higher mean plasma glucose concentration after a standard oral glucose tolerance test than those who were exclusively breast fed. They also had a higher plasma low density lipoprotein (LDL) cholesterol concentration, a lower high density lipoprotein (HDL) cholesterol concentration, and a higher LDL/ HDL ratio. Systolic blood pressure and body mass index were not affected by the method of infant feeding. Ravelli-ACJ et al. "Infant feeding and adult glucose tolerance, lipid profile, blood pressure, and obesity." Archives-Of-Disease-In-Childhood. MAR 2000; 82 (3) : 248-252.

After adjustment for age, height, and sibship, and taking into account current diet and parental hypercholesterolemia, cholesterol concentration was lower in boys who had been breast fed This study provides evidence that diet in infancy may have longstanding effect on lipid metabolism. Plancoulaine-S et al. "Infant-feeding patterns are related to blood cholesterol concentration in prepubertal children aged 5-11y." European Journal of Clinical Nutrition. Feb 2000; 54 (2) : 114-119.

5. Celiac Disease


In this case-control study, 143 children with celiac disease and 137 randomly recruited gender- and age-matched control children were administered a standardized questionnaire. The risk of developing celiac disease decreased significantly by 63% for children breast-fed for more than 2 months (OR 0.37) as compared with children breast-fed for 2 months or less. The age at first gluten introduction had no significant influence on the incidence of celiac disease (OR 0.72 comparing first gluten introduction into infant diet >3 months vs. less than or equal to3 months). Conclusion: A significant protective effect on the incidence of celiac disease was suggested by the duration of breast-feeding (partial breastfeeding as well as exclusive breast-feeding). The data did not support an influence of the age at first dietary gluten exposure on the incidence of celiac disease. However, the age at first gluten exposure appeared to affect the age at onset of symptoms. Peters U et al. "A case-control study of the effect of infant feeding on celiac disease." Annals-Of-Nutrition-And-Metabolism. Jul-Aug 2001; 45 (4) : 135-142.

Celiac disease is characterized by lethargy, megoblastic anemia, malabsorption, and GI symptoms caused by allergy to gluten. Prolonged breastfeeding, at least until the 6th month, and gluten introduction started at least at the 5th month of life, significantly delay the onset of the disease. Gluten introduction should be done progressively and under breast feeding protection. Introduction of gluten 2 months before weaning has a protective effect. Bouguerra F et al. [Breast feeding effect relative to age of onset of celiac disease]. Arch Pediatr 1998 Jun;5(6):621-6

Children formula-fed from birth, or breast-fed for less than 30 days, were found to have a relative risk of developing symptoms of celiac disease four times higher than children breast-fed for more than 30 days. Auricchio S et al. "Does breast feeding protect against the development of clinical symptoms of celiac disease in children?" J Pediatr Gastroenterol Nutr 1983;2(3):428-33


6. Dental Health


This systematic review investigated the relationship between early childhood caries and breastfeeding. A lack of methodological consistency, related to the study of the association of breastfeeding and ECC, and inconsistent definitions of ECC and breastfeeding, make it difficult to draw conclusions. Due to conflicting findings in less. rigorous research studies, no definitive time at which an infant should be weaned was determined, and parents should begin an early and consistent mouth care regime. Valaitis R, et al. A systematic review of the relationship between breastfeeding and early childhood caries. Canadian-Journal-Of-Public-Health-Revue-Canadienne-De-Sante-Publique. Nov-Dec 2000; 91(6) : 411-417

In this study of 260 children ages 3-5, the authors concluded that breastfeeding for more than 40 days may act preventively and inhibit the development of nursing caries in children. Oulis CJ et al. "Feeding practices of Greek children with and without nursing caries." Pediatr Dent 1999 Nov-Dec;21(7):409-16

This study estimated the prevalence of early childhood caries and related behavioral risk factors in a population of low-income, Mexican-American children in Stockton, California. Data was collected on 220 children ages six years or less using a parent-completed questionnaire and clinical dental examinations. Mean age at weaning from breast-or bottle-feeding and patterns of bottle use during sleep did not differ significantly between children with caries and those without. Ramos-Gomez-FJ et al. "Assessment of early childhood caries and dietary habits in a population of migrant Hispanic children in Stockton, California." Journal-Of-Dentistry-For-Children 1999; 66 (6): 395-403, 366

This in-vivo and in-vitro study showed that human breast milk is not cariogenic. Erickson PR, Mazhari E. "Investigation of the role of human breast milk in caries development." Pediatr Dent 1999 Mar-Apr;21(2):86-90

Children who were either never breast-fed or only until 3 months exhibited a significantly higher caries prevalence than those breast-fed for a longer time. Mattos-Graner RO et al. "Association between caries prevalence and clinical, microbiological and dietary variables in 1.0 to 2.5-year-old Brazilian children. Caries Res 1998;32(5):319-23

A strong association was found between exclusive bottle-feeding and anteroposterior malocclusion. Davis DW, Bell PA. "Infant feeding practices and occlusal outcomes: a longitudinal study." J Can Dent Assoc 1991 Jul;57(7):593-4

Among breastfed infants, the longer the duration of nursing the lower the incidence of malocclusion. Labbok, M.H. "Does Breast Feeding Protect against Malocclusion? An Analysis of the 1981 Child Health Supplement to the National Health Interview Survey". American Journal of Preventive Medicine, 1987.

7. Diabetes Mellitus


Bovine beta-casein is a cow's milk protein that targets both humoral and cellular immune responses in patients with Type 1 diabetes and, to a lesser degree, also in normal subjects. This study aimed to determine whether the avoidance of cow's milk consumption early in life could prevent the development of antibody response to bovine beta-casein despite the mother being exposed on a daily basis to cow's milk consumption. The researchers measured the antibody response to bovine beta -casein in 28 healthy infants under 4 months of age, of whom 16 were exclusively breast-fed and 12 were bottle-fed with cow's milk. In addition, beta -casein antibodies were measured in 37 prepubertal children with Type 1 diabetes and in 31 healthy children who were exposed to cow's milk or dairy products to see whether differences in antibody titers exist in this young age group. Antibodies binding to beta -casein were also evaluated. Elevated levels of beta -casein antibodies were found in bottle-fed infants compared to breast-fed infants (p < 0.0001). Antibody levels to bovine <beta>-casein were also significantly higher in children with Type 1 diabetes compared to age-matched controls (p = 0.03). The authors confirmed specific binding to bovine beta-casein in bottle-fed infants, in children with Type 1 diabetes and in controls exposed to cow's milk, but not in infants who were exclusively breast-fed. The results of this study indicate that breastfeeding within the first 4 months of life prevents the generation of antibody response to bovine beta -casein despite the mothers' consumption of cow's milk during the breastfeeding period. Monetini L. "Bovine beta-casein antibodies in breast- and bottle-fed infants: their relevance in Type 1 diabetes." Diabetes-Metabolism-Research-And-Reviews. Jan-Feb 2001; 17 (1) : 51-54


This study aimed to establish the relation between early infant nutrition and signs of beta-cell autoimmunity in young children.Methods. We identified and observed from birth 2949 infants with increased genetic risk of Type I (insulin-dependent) diabetes mellitus and monitored them for islet cell antibodies at 3 to 6 month intervals. This case-control study comprises the first 65 children who seroconverted to islet cell antibody positivity before the age of 4 years and 390 control children who were islet cell antibody-negative (six control children/case). Infants who had been breastfed exclusively for at least 4 months had lower risk of seroconversion to positivity for IA-2A or all four autoantibodies [odds ratio 0.24] than those infants who had been breastfed exclusively for less than 2 months. The risk of seroconversion was higher in those younger than 2 months (OR 4.37) or aged 2 to 3.9 months (OR 5.50) when they first received cows' milk than in those aged 4 months or older. These observations suggest that short-term breastfeeding and the early introduction of cows' milk-based infant formula predispose young children who are genetically susceptible to Type I diabetes to progressive signs of beta-cell autoimmunity. Kimpimaki-T, et al. "Short-term exclusive breastfeeding predisposes young children with increased genetic risk of Type I diabetes to progressive beta-cell autoimmunity." Diabetologia-. Jan 2001; 44 (1) : 63-69

A population-based case-control study of 196 children with type 1 diabetes and 325 age- and sex-matched control subjects found a significantly raised risk for illnesses in the neonatal period (OR 1.61), the majority of which were infections and respiratory difficulties. Exclusive breast feeding as the initial feeding method was significantly protective (OR 0.65). McKinney et al. "Perinatal and neonatal determinants of childhood type 1 diabetes. A case-control study in Yorkshire, U.K." Diabetes Care 1999 Jun;22(6):928-32

Diabetes is less common among breast-fed children (6.9 and 30.1% among offspring of nondiabetic and diabetic women, respectively) than among bottle-fed children (11.9 and 43.6%, respectively). Pettitt DJ, Knowler WC. "Long-term effects of the intrauterine environment, birth weight, and breast-feeding in Pima Indians." Diabetes Care 1998 Aug;21 Suppl 2:B138-41

Children who developed IDDM in New South Wales, Australia, were compared to healthy children of the same sex and age. Those who were exclusively breastfed during their first three months of life had a 34% lower risk of developing diabetes than those who were not breastfed. Children given cow's-milk-based formula in their first three months were 52% more likely to develop IDDM than those not given cow's milk formula. Diabetes Care 1994;17:1381-1389, 1488-1490.

8. Helicobacter pylori infection


Serum H pylori IgG antibodies were measured in 631 men and 389 women born during 1920-30. Independent of their current social class, subjects were more likely to be H pylori seropositive if they had large numbers of siblings, and if they had lived in a crowded house, or shared a bedroom or bed in childhood. Low weight at 1 year was associated with increased seropositivity rates in men, but not women. Men and women who were breast fed in infancy were less likely to be seropositive than those who were bottle fed. Fall CH, Goggin PM, Hawtin P, Fine D, Duggleby S. "Growth in infancy, infant feeding, childhood living conditions, and Helicobacter pylori infection at age 70." Arch Dis Child 1997 Oct;77(4):310-4

9. Haemophilus Influenzae Meningitis


A strong negative correlation between breastfeeding and incidence of Haemophilus influenzae infection 5 to 10 years later. Silfverdal SA et al. "Protective effect of breastfeeding: an ecologic study of Haemophilus influenzae meningitis and breastfeeding in a Swedish population." Int J Epidemiol 1999 Feb;28(1):152-6

10. Inflammatory Bowel Disease (Crohn's Disease, Ulcerative Colitis)


Twenty-six cases of Crohn's disease and 29 cases of ulcerative colitis were matched for gender and social class with controls. There was a trend that those with Crohn's disease were more likely not to have been breast-fed (OR 0.4). The prevalence of inflammatory bowel disease was 5.12/1000 by the age of 43 years. Thompson-NP; Montgomery-SM; Wadsworth-MEJ; Pounder-RE; Wakefield-AJ. "Early determinants of inflammatory bowel disease: use of two national longitudinal birth cohorts. European Journal of Gastroenterology and Hepatology. Jan 2000; 12 (1):25-30

Lack of breastfeeding in infancy was associated with an increased risk of ulcerative colitis (chronic inflammatory disorder of the colon) and Crohn's disease (chronic inflammatory disorder affecting any part of the gut, aggravated by food intolerance). Corrao G et al. "Risk of inflammatory bowel disease attributable to smoking, oral contraception and breastfeeding in Italy: a nationwide case-control study." Int J Epidemiol 1998 Jun;27(3):397-404

Lack of breastfeeding was a risk factor associated with later development of Crohn's disease. Koletzko, S., "Role of Infant Feeding Practices in Development of Crohn's Disease in Childhood". Br Med J, 1989

11. Juvenile Rheumatoid Arthritis (JRA)


Children who have had JRA, especially pauciarticular JRA, are less likely to have been breastfed than controls, suggesting that breast feeding may have a protective effect on the development of JRA. Lower odds ratio were noted for increased durations of breast feeding. Mason T et al. "Breast feeding and the development of juvenile rheumatoid arthritis." J Rheumatol 1995 Jun;22(6):1166-70

12. Multiple Sclerosis


Although thought to be multifactorial in origin, and without a clearly defined etiology, lack of breastfeeding does appear to be associated with an increased incidence of multiple sclerosis. Dick, G. "The Etiology of Multiple Sclerosis." Proc Roy Soc Med 1976;69:611-5

Pisacane A, et al. Breast feeding and multiple sclerosis. BMJ 1994 May 28;308(6941):1411-2.

13. Obesity


In this Harvard survey of 8186 girls and 7155 boys, aged 9 to 14 years, overweight status was defined as body mass index exceeding the 95th percentile for age and sex from US national data. In the first 6 months of life, 9553 subjects (62%) were only or mostly fed breast milk, and 4744 (31%) were only or mostly fed infant formula. A total of 7186 subjects (48%) were breastfed for at least 7 months while 4613 (31%) were breastfed for 3 months or less. At ages 9 to 14 years, 404 girls (5%) and 635 boys (9%) were overweight. Among subjects who had been only or mostly fed breast milk, compared with those only or mostly fed formula, the odds ratio (OR) for being overweight was 0.78, after adjustment for age, sex, sexual maturity, energy intake, time watching television, physical activity, mother's body mass index, and other variables reflecting social, economic, and lifestyle factors. Compared with subjects who had been breastfed for 3 months or less, those who had been breastfed for at least 7 months had an adjusted OR for being overweight of 0.80. Timing of introduction of solid foods, infant formula, or cow's milk was not related to risk of being overweight. Infants who were fed breast milk more than infant formula, or who were breastfed for longer periods, had a lower risk of being overweight during older childhood and adolescence. Gillman MW et al. Risk of Overweight Among Adolescents Who Were Breastfed as Infants. JAMA 2001 May 16;285(19):2461-2467.

A German study of 9357 children aged 5-6 years of age found that infants fed only breastmilk until 3-5 months were more than a third less likely to be obese than infants fed formula from the start. Infants breastfed exclusively for 6-12 months were 43% less likely to be obese. Breastfeeding beyond 12 months was better still, giving infants a 72% lower chance of becoming obese children. After adjusting for potential confounding factors, breastfeeding remained a significant protective factor against the development of obesity. von Kries, R. "Breast feeding and obesity: cross sectional study." BMJ 1999; 319: 147-150.

This Swedish study examined the relations between length of breast-feeding, growth, and body composition in a group of 781 adolescents. Data on feeding pattern in infancy and on weight and height from birth up to 18 years were collected. Both boys and girls who were exclusively breast-fed for more than 3 months were leaner and showed a trend towards lower skinfold values. Tulldahl J, Pettersson K, Andersson SW, Hulthen L. "Mode of infant feeding and achieved growth in adolescence: early feeding patterns in relation to growth and body composition in adolescence."
Obes Res 1999 Sep;7(5):431-7

14. Parent-child relationships


Children who were breast fed for a longer duration were more likely, at age 15-18 years, to report higher levels of parental attachment and tended to perceive their mothers as being more caring and less overprotective towards them compared with bottle-fed children. After adjustment for maternal and perinatal factors, the duration of breastfeeding remained significantly associated with adolescent perceptions of maternal care, with increasing duration of breast feeding being associated with higher levels of perceived maternal care during childhood. Fergusson DM, Woodward LJ. "Breast feeding and later psychosocial adjustment." Paediatr Perinat Epidemiol 1999 Apr;13(2):144-57

15. Tonsillitis


Pisacane A, et al. Breast feeding and tonsillectomy. BMJ. 1996 Mar 23;312(7033):746-7.

16. Transplant recipients


A history of breastfeeding was associated with dramatic improvements in graft function rates after sibling donor as well as maternal donor transplantation. Kois WE et al. Influence of breast feeding on subsequent reactivity to a related renal allograft. J Surg Res. 1984 Aug;37(2):89-93.

The posttransplant course of 55 patients who had received a primary maternal-donor transplant was studied. A history of breast feeding was associated with a more favorable posttransplant course as measured by the percentage of patients who had no rejection episodes during the first posttransplant year. The one-year graft function rate for breast-fed recipients was 82%; this was statistically significantly better than the 57% measured for non-breast-fed recipients. Campbell DA et al. Breast feeding and maternal-donor renal allografts. Transplantation 1984 Apr;37(4):340-4.

17. Vaccine Response


The antibody levels of immunized infants were significantly higher in the breastfed than the formula-fed group. These findings are strong evidence that breastfeeding enhances the active humoral immune response in the first year of life. Papst, H.F. , Spady, D.W. "Effect of Breast Feeding on Antibody Response to Conjugate Vaccine". Lancet, 1990

The breastfed group had significantly higher antibody levels than two formula-fed groups together. Breastfed infants thus showed better serum and secretory responses to perioral and parenteral vaccines than the formula fed, whether with a conventional or low-protein content. Van-Coric, M. "Antibody Responses to Parental & Oral Vaccines Where Impaired by Conventional and Low-Protein Formulas as Compared to Breast Feeding". Acta Paediatr Scand 1990; 79: 1137-42


II. Maternal Effects


A. Cancer

1. Breast Cancer


Women who breastfed a child for more than 24 months had a 54% reduced risk of developing breast cancer compared with women who breastfed for no more than 6 months. Women who breastfed for at least 73 months over the course of their lives had a much lower risk of breast cancer. The investigators found that the protective effect of breastfeeding applied to a woman's risk of developing breast cancer both before and after menopause. Also confirmed that the later age of menarche and first pregnancy at a younger age lowers breast cancer risk. Women who went through menopause later and those with a family history of breast cancer were at increased risk. Zeng T et al. Long-term Breastfeeding Lowers Mother's Breast Cancer Risk. Am J Epidemiol 2001; 152:1129-1135.

This study compared rates of breast cancer between 751 mothers who had breastfed at least once and 743 mothers who had not. Breastfeeding reduced the risk of breast cancer by 20% in women age 20 to 49 years and by 30% in women ages 50 to 74 years. Moreover, breastfeeding seemed to protect against breast cancer regardless of the number of children breastfed, mother's age at first and last lactation, and menstrual history. R. Millikan et al. International Journal of Epidemiology 1999; 28:396-402.

This study investigated the relationship between reproductive events during adolescence and subsequent breast cancer risk. in 862 case patients and 790 controls in the Carolina Breast Cancer Study. Miscarriage, induced abortion, and full-term pregnancy before 20 years of age were not associated with breast cancer. Among premenopausal women, breast-feeding before 20 years of age was inversely associated with disease. Oral contraceptive use before 18 years of age was positively associated with disease risk among African American women only. Marcus PM, Baird DD, Millikan RC, Moorman PG, Qaqish B, Newman B. Adolescent reproductive events and subsequent breast cancer risk. Am J Public Health 1999 Aug;89(8):1244-7

As part of a multicenter population-based case-control study, the authors examined postmenopausal breast cancer risk according to breastfeeding characteristics. This analysis included only data on parous postmenopausal women (3,633 cases and 3,790 controls). After adjustment for age, parity, age at first birth, and other breast cancer risk factors, breastfeeding for at least 2 weeks was associated with a slightly reduced risk of breast cancer in comparison with women who had never lactated (relative risk = 0.87). There was only a modest suggestion that increasing cumulative duration of lactation was inversely associated with breast cancer risk; the relative risk for women who had breastfed for > or =24 months was 0.73. Age at first lactation was not consistently associated with risk. Modest inverse associations appeared to persist even up to 50 years since first lactation. Use of hormones to suppress lactation was not associated with postmenopausal breast cancer, nor was inability to breastfeed related to risk. These results suggest that lactation may have a slight and perhaps long-lasting protective effect on postmenopausal breast cancer risk. Newcomb PA et al. "Lactation in relation to postmenopausal breast cancer."
Am J Epidemiol 1999 Jul 15;150(2):174-82

If women who do not breastfeed or who breastfed for less than 3 months were to do so for 4 to 12 months, breast cancer among parous premenopausal women could be reduce by 11%. If all women with children lactated for 24 months or longer, the incidence might be reduced by nearly 25%. Newcomb, P. et al. "Lactation and reduced risk of premenopausal breast cancer." N Engl J Med 1994; 330(2):81-87.

After controlling for age at first full term pregnancy and other potentially compounding factors, parity and duration of breast feeding also had a strong influence on the risk of breast cancer. Compared with parous women who never breastfed, women who had breastfed for 25 months or more had a lower relative risk. Layde, P.M., "The Independent Associations of Parity Age at First full Term Pregnancy, and Duration of Breast Feeding with the Risk of Breast Cancer." Journal of Clinical Epidemiol, 1989.

Among both premenopausal and postmenopausal women, risk of breast cancer decreases with increasing duration of lifetime lactation experience although the effect was consistently stronger for premenopausal women. McTieman, A., Evidence of Protective Effect of Lactation on Risk of Breast Cancer in Young Women." American Journal of Epidemiology, 1986


2. Endometrial Cancer


Lactation provides a hypoestrogenic effect with less stimulation of the endometrial lining. This event may offer a protective effect from endometrial cancer. Petterson B, et al. "Menstruation span- a time limited risk factor for endometrial carcinoma". Acta Obstet Gyneocol Scand 1986;65:247-55

3. Esophageal Cancer


Breastfeeding was associated with reduced risk of subsequently developing this cancer (OR = 0.41) and there was a significant dose-response effect. Cheng-KK et al. "A case-control study of oesophageal adenocarcinoma in women: a preventable disease." British-Journal-Of-Cancer. Jul 2000; 83 (1) : 127-132

4. Ovarian Cancer


563 cases in Massachusetts and New Hampshire were ascertained from hospitals and statewide tumour registries; control women (n = 523) were selected randomly and matched to case women. Ovarian cancer risk was reduced among parous women, relative to nulliparous women (OR = 0.4). Among parous women, higher parity (P = 0.0006), increased age at first (P = 0.03) or last (P = 0.05) birth, and time since last birth (P = 0.04) were associated with reduced risk. Early pregnancy losses, abortions, and stillbirths were unrelated to risk, but preterm, term, and twin births were protective. Risk was lower among women who had breast-fed. relative to those who had not (OR = 0.7), but the average duration of breast-feeding per child was unrelated to risk. Age at menarche and age at menopause were unrelated to risk overall, although increasing menarcheal age was protective among premenopausal women (P = 0.02). Menstrual cycle characteristics and symptoms were generally unrelated to risk, although cycle-related insomnia was associated with decreased risk (OR = 0.5). No association was found between the type of sanitary product used during menstruation and ovarian cancer risk. In analyses by histologic subtype, reproductive and menstrual factors had most effect on risk of endometrioid/clear cell tumours, and least influential with regard to risk of mucinous tumours. Titus-Ernstoff L. "Menstrual and reproductive factors in relation to ovarian cancer risk." British-Journal-Of-Cancer. Mar 2 2001; 84 (5) : 714-721

Cases 20-69 years of age with a recent diagnosis of epithelial ovarian cancer (767) were compared with community controls (1367). A number of reproductive and contraceptive factors that suppress ovulation, including gravidity, breastfeeding, and oral contraception, reduced the risk of ovarian cancer. Environmental factors and medical conditions that increased risk included talc use, endometriosis, ovarian cysts, and hyperthyroidism. Gynecologic surgery including hysterectomy and tubal ligation were protective. Ness-RB et al. "Factors related to inflammation of the ovarian epithelium and risk of ovarian cancer." Epidemiology-. Mar 2000; 11 (2) : 111-117

Breastfeeding seems to be somewhat protective against ovarian cancer, but only before menopause. Siskind V et al. "Breastfeeding, menopause, and epithelial ovarian cancer. Epidemiology 1997 Mar;8(2):188-91

Decreased risks of epithelial ovarian cancer in black women were associated with parity of four or higher, breast-feeding for 6 months or longer, and use of oral contraceptives for 6 years or longer. John EM et al. "Characteristics relating to ovarian cancer risk: collaborative analysis of seven U.S. case-control studies. Epithelial ovarian cancer in black women. J Natl Cancer Inst 1993 Jan 20;85(2):142-7

A marked reduction in risk was associated with ever having breast fed. Gwinn ML et al. "Pregnancy, breast feeding, and oral contraceptives and the risk of epithelial ovarian cancer. J Clin Epidemiol 1990;43(6):559-68

Breastfeeding should be added to the list of factors that decrease ovulatory age and thereby decrease the risk of ovarian cancer. Schneider, A.P. "Risk Factor for Ovarian Cancer. "New England Journal of Medicine, 1987

5. Thyroid Cancer


Individually matched case-control study (292 pairs) of female thyroid cancer patients found that risk increased with number of pregnancies in women using lactation suppressants and decreased with duration of breastfeeding. Mack WJ et al, "Reproductive and hormonal risk factors for thyroid cancer in Los Angeles County females." Cancer Epidemiol Biomarkers Prev 1999 Nov;8(11):991-7

6. Uterine Cancer


A protective effect against uterine cancer was found for women who breastfeed. Brock, K.E., "Sexual, Reproductive, and Contraceptive Risk Factors for Carcinoma-in-Situ of the Uterine Cervix in Sidney. "Medical Journal of Australia, 1989.


B. Emotional Health

Significant changes occur in women's personality during pregnancy and lactation. The trend is toward a lifestyle interpreted as more relaxed and tolerant to monotony. In this study of 161 women during pregnancy and 3-6 months after delivery, women who had breastfed for at least 8 weeks differed significantly from those who had not. They had lower scores on the Somatic Anxiety, Muscular Tension, Monotony Avoidance, Suspicion, Social Desirability and the Impulsiveness scale and higher scores on the Socialization scale. Sjogren-B et al. "Changes in personality pattern during the first pregnancy and lactation." Journal-Of-Psychosomatic-Obstetrics-And-Gynecology. Mar 2000; 21 (1):31-38.

Personality profiles reflecting anxiety and social interaction showed that anxiety was inversely related with basal levels of oxytocin and prolactin in the cesarean section mothers, whereas the pulsatility of oxytocin was related to social desirability in both groups. Social desirability and oxytocin pulsativity were also correlated with the amount of milk transferred from the mother to the baby. The correlations indicate that central oxytocin may be involved in behavioral adaptations to the maternal role. Nissen E, Gustavsson P, Widstrom AM, Uvnas-Moberg K. "Oxytocin, prolactin, milk production and their relationship with personality traits in women after vaginal delivery or Cesarean section." J Psychosom Obstet Gynaecol 1998 Mar;19(1):49-58

In both male and female rats, oxytocin exerts potent physiological antistress effects. If daily oxytocin injections are repeated over a 5-day period, blood pressure is decreased by 10-20 mmHg, the withdrawal latency to heat stimuli is prolonged, cortisol levels are decreased and insulin and cholecystokinin levels are increased. These effects last from 1 to several weeks after the last injection. After repeated oxytocin treatment weight gain may be promoted and the healing rate of wounds increased. Oxytocin released in response to social stimuli may be part of a neuroendocrine substrate which underlies the benefits of positive social experiences. Uvnas-Moberg K. "Oxytocin may mediate the benefits of positive social interaction and emotions." Psychoneuroendocrinology 1998 Nov;23(8):819-35

At one month postpartum, women who breast fed their infants had scores indicating less anxiety and more mutuality than the women bottle feeding their infants. Virden, S.F., "The Relationship Between Infant Feeding Method and Maternal Role Adjustment." Journal of Nurse Midwives, 1988 Jan-Feb;33(1):31-5.


C. Fertility

During lactation, menses before 6 months are mostly anovulatory, and fertility remains low. The lactational amenorrhea method is based on three simultaneous conditions: (1) the baby is under 6 months; (2) the mother is still amenorrheic; and (3) she practices exclusive or quasi-exclusive breastfeeding on demand, day and night. Experiments with LAM extended to 9-12 months are ongoing. The lactational amenorrhea method is at least 98% effective. Vekemans M. "Postpartum contraception: the lactational amenorrhea method." Eur J Contracept Reprod Health Care 1997 Jun;2(2):105-11


D. Insulin Requirements

Breastfeeding decreased insulin requirements in diabetic women. Reduction in insulin dose postpartum was significantly greater in those who were breastfeeding than those who were bottle feeding. Davies, H.A., "Insulin Requirements of Diabetic Women who Breast Feed." British Medical Journal, 1989 May 20;298(6684):1357-8.


E. Osteoporosis

The odds ratio that a woman with osteoporosis did not breastfeed her baby was 4 times higher than for a control woman. Blaauw, R. et al. "Risk factors for development of osteoporosis in a South African population." SAMJ 1994; 84:328-32.

Whether or not women had ever breastfed, total duration of breastfeeding and duration of breastfeeding per child were not associated with reduced bone mineral, but breastfeeding for more than 8 months was associated with greater bone mineral at some sites. Melton L et al. "Influence of breastfeeding and other reproductive factors on bone mass later in life." Osteoporos Int 1993 Mar;3(2):76-83


F. Postpartum Weight Loss


Infants were exclusively breastfed for 4 months and then randomly assigned to continue exclusive breastfeeding until 6 months or to receive solid foods in addition to breast milk between 4 and 6 months. Maternal weight loss between 4 and 6 months was significantly greater in the exclusive breastfeeding group than in the group given solid foods. The estimated average additional nutritional burden of continuing to exclusively breastfeed until 6 months was small, representing only 0.1 to 6% of the recommended dietary allowance for energy, vitamin A, calcium and iron. Women in the exclusive breastfeeding group were more likely to be amenorrheic at 6 mo than women in the SF group, which conserves nutrients such as iron.

Dewey KG et al. Effects of exclusive breastfeeding for four versus six months on maternal nutritional status and infant motor development: results of two randomized trials in Honduras. J Nutr 2001 Feb;131(2):262-7

Mothers who breastfed exclusively or partially had significantly larger reductions in hip circumference and were less above their prepregnancy weights at 1 month postpartum than mothers who fed formula exclusively. Kramer, F., "Breastfeeding reduces maternal lower body fat." J Am Diet Assoc 1993;93(4):429-33


G. Urinary Tract Infections

The oligosaccharide content of breast-milk and urine from nursing mothers is very similar, and the pattern of oligosaccharides excreted by infants is also strongly correlated with that of breastmilk. The oligosaccharides cause inhibition of bacterial adhesion, suggesting that breastfeeding may have a preventive effect on urinary tract infection in both mother and infant. Coppa GV et al. "Preliminary study of breastfeeding and bacterial adhesion to uroepithelial cells." Lancet 1990 Mar 10;335(8689):569-71


III. Societal Effects


A. Child Abuse

Encouraging early mother-infant contact with suckling and rooming-in may provide a simple, low-cost method for reducing infant abandonment. The mean infant abandonment rate decreased from 50.3 per 10,000 births in the first 6 years to 27.8 per 10,000 births in the next 6 years following implementation of the Baby-Friendly Hospital Initiative at a Russian hospital. Lvoff-NM et al. Effect of the baby-friendly initiative on infant abandonment in a Russian hospital. Archives-Of-Pediatrics-And-Adolescent-Medicine. MAY 2000; 154(5):474-477.

A retrospective review of 800 pregnancies at one family practice revealed an association between lack of breastfeeding and physical and sexual abuse of the mother and/or her children. This anecdotal association has not been previously reported, is worth further study using more rigorous methods. Acheson, L., "Family Violence and Breast-feeding" Arch Fam Med July 1995; Vol 4,pp 650-652.


B. Child Spacing

Retrospective and prospective data show that: (a) a short preceding birth interval is detrimental for child survival in the first 4 months of life; (b) full and partial breast-feeding have direct protective effects on child survival in the first 4-6 months of life, with the effects of the former stronger than those of the latter; (c) early subsequent conception significantly increases mortality risks in the first 16 months of life of the index child. These findings are robust to various controls, e.g. study design, data defects, child's health conditions at/around birth, postnatal maternal and child recurrent illnesses, patterns of utilization of health care services, and immunization status of the child. Kuate D. "Effects of infant feeding practices and birth spacing on infant and child survival: a reassessment from retrospective and prospective data." J Biosoc Sci 1997 Jul;29(3):303-26

Sufficient birth spacing helps with the survival of the older sibling and the new infant. Prolonged lactation helps to promote the spacing of children. Thapa, S., "Breastfeeding, birth spacing and their effects on child survival." Nature 1988;335:679-82


C. Environment

There is less use of natural resources (glass, plastic, metal, and paper used in bottles, bags, nipples, and formula cans) and also less waste for landfills.


D. Financial Cost to Government and Families

1. Food Expense


The cost to supply artificial baby milk (ABM) to one child is between $1,160 and $3,915 per year depending on the brand. Even mothers on WIC need to buy approximately 200 cans of concentrate to feed her infant in the first year. Breastfeeding Support Consultants, Information on Infant Feeding Costs, April 1998 (based on Illinois and North Carolina suburban supermarket prices).

2. Medical Expenses


A minimum of $3.6 billion would be saved if breastfeeding were increased from current levels (64 percent in-hospital, 29 percent at 6 months) to those recommended by the U.S. Surgeon General (75 and 50 percent). This figure is likely an underestimation of the total savings because it represents cost savings from the treatment of only three childhood illnesses: otitis media, gastroenteritis, and necrotizing enterocolitis. This report reviews breastfeeding trends and previous studies that assessed the economic benefits of breastfeeding. Weimer, D. The Economic Benefits of Breastfeeding: A Review and Analysis. Economic Research Service, US Department of Agriculture, Food Assistance and Nutrition Research Report No. 13. 20 pp, March 2001, http://www.ers.usda.gov/publications/fanrr13/

In the first year of life, after adjusting for confounders, there were 2033 excess office visits, 212 excess days of hospitalization, and 609 excess prescriptions for these three illnesses per 1000 never-breastfed infants compared with 1000 infants exclusively breastfed for at least 3 months. These additional health care services cost the managed care health system between $331 and $475 per never-breastfed infant during the first year of life. Ball TM, Wright AL. "Health care costs of formula-feeding in the first year of life." Pediatrics 1999 Apr;103(4 Pt 2):870-6

Compared with formula-feeding, breast-feeding each infant enrolled in WIC saved $478 in WIC costs and Medicaid expenditures during the first 6 months of the infant's life. Montgomery DL, Splett PL. "Economic benefit of breast-feeding infants enrolled in WIC." J Am Diet Assoc 1997 Apr;97(4):379-85

If women breast-fed each child for at least 6 months, the total projected savings over a 7.5-year period ranges from $3,442 to $6,096 per family. This translates into an estimated yearly savings of between $459 and $808 per family. Savings were calculated based on estimates of the resulting decrease in infant morbidity, maternal fertility, and formula purchases. Tuttle CR, Dewey KG. "Potential cost savings for Medi-Cal, AFDC, food stamps, and WIC programs associated with increasing breast-feeding among low-income Hmong women in California. J Am Diet Assoc 1996 Sep;96(9):885-90

A pre-publication study by the Wisconsin State Breastfeeding Coalition estimated the following health care savings in Wisconsin if Breastfeeding rates were at 75% at discharge-50% at six months:

$4,645,250/yr Acute Otitis Media

$437,120/yr Bronchitis

$6,699,600/yr Gastroenteritis

$262,440/yr Allergies

$758,934/yr Asthma

$578,500/yr Type I Diabetes (birth - 18 yrs)

$17,070,000/yr Breast Cancer



E. Vaccine Effectiveness

Breastfed infants showed a better serum and secretory responses to oral and parenteral vaccines than the formula-fed, whether with a conventional or low protein content. Han-Zoric, M., "Antibody responses to parenteral and oral vaccines are impaired by conventional and low protein formulas as compared to breastfeeding." Acta Paediatr Scand 1990; 79:1137-42