Breastfeeding Benefits & Barriers: Immunologic Advantages

Breastfeeding delivers immunologic advantages to the baby

It was noted in the early 1970's that infants in the developing world who were fed formula had a much higher death rate than infants who were fed breast milk. This was due to malnutrition and recurrent infectious diseases.

In the mid 1990's, exclusive breastfeeding was associated with decreased death rates due to acute respiratory infections and diarrhea in infants aged 1 to 11 months in Bangladesh when compared to infants who were partially breastfed (breastfed with the addition of other milks, and/or supplementary foods) ( Arifeen, 2001 ).

The causes for this were:

1. Bacterial contamination of the water used to make formula.

2. Bacterial contamination of the infant feeding bottles.

3. Decrease in nutrition due to recurrent episodes of infectious gastroenteritis caused by bacterial contamination of the formula.
   In Bangladesh, breastfeeding has been found to be protective against Shigella into the third year of life ( Ahmed, 1992 ). Breastfeeding was also found to be protective against Enterotoxigenic E. Coli in the first year of life ( Clemens, 1997 ).
   In Mexico, breastfeeding was associated with decreased incidence of Giardia infection ( Morrow, 1992 ).

4. If money is lacking, the formula is watered down so that it lasts longer, and this obviously decreases nutrition ( Jelliffe, 1978 pgs 211-241, Habicht, 1988 ). Presently, a day's supply of infant formula costs about $2.50 in the United States. The cost is very similar in the developing world where family income may be $100 - $200 a month.

The mother of this malnourished 11 month old died in a refugee camp when he was 3 months old and weighed 3.4 Kg. He was then fed a mixture of two large spoons of sweetened condensed milk in 8 ounces of water for 8 months. He weighed 3.8 Kg. when hospitalized.

Anti-infective properties that are found in breast milk include the following:

1. Immunoglobulins IgA, IgM, IgG
2. Complement
3. Chemotactic factors
4. Lactoferrin
5. Lysozyme
6. Lactobacillis Bifidus growth factor
7. Cytokines
8. Macrophages
9. T and B cell lymphocytes
10. Plasma and neutrophils
11. Interleukins

This list is growing as more substances are discovered. Further information on these substances can be found in the following references: Lawrence, 2005 p. 171-214, Welsh, 1979 , Slusser, 1997 .

Some studies on the health of breast fed babies in the developed world, where sanitation is good and where money is available to buy formula, did not show that breast milk was effective in preventing infection in infants ( Rubin,1990 , Bauchner, 1986 ). Of the studies published since 1990 only Rubin's did not show an effect of breastfeeding on infection rates in infants.

Studies that have found a decreased incidence of infectious diseases in breast fed versus formula fed infants in middle class societies in the developed world are summarized below.

1. Breastfeeding and otitis media:
   1. Duncan studied a middle class Tucson, Arizona population, and found that exclusive breastfeeding for four months delayed the first episode of otitis media and decreased recurrent otitis media ( Duncan, 1993 ).

   2. In Finland, the incidence of recurrent otitis media was inversely correlated with the duration of breastfeeding ( Saarinen, 1982 ).

   3. Infants with cleft palate who were fed their mother's milk from a bottle had less otitis media than infants who were fed formula ( Paradise, 1994 ).

   4. Duffy found that peak incidence of acute otitis media was inversely related to rates of breastfeeding beyond 3 months. Approximately 50% of infants exclusively breast fed for 6 months had a first episode of otitis media by 12 months of age, compared to 76% of exclusively formula fed infants ( Duffy, 1997 ).

2. Breastfeeding and wheezing:
   1. In Tucson, infants who were breast fed for a month had a decreased incidence of wheezing associated illness in the first year of life ( Wright, 1995 ).

   2. Studies from Britain showed that infants who were breast fed had fewer hospital admissions for bronchiolitis ( Pullan, 1980 , Downham, 1976 ).

   3. A case control study in a population of Alaska native children found that having ever been breastfed more than half of feedings or having been breastfed within 8 weeks of age at admission for RSV infection was protective against hospitalization for RSV infection ( Bulkow, 2002 ).

   4. Fischaut showed that a mother who developed respiratory syncytial virus infection (RSV) while she was breast feeding her infant produced increased RSV specific antibodies in her breast milk ( Fishhaut, 1981 ).

   5. Preliminary work on an experimental RSV vaccine that was given to women in the immediate post partum period produced high levels of RSV specific antibody in the women and in their breast milk for at least 12 weeks after immunization ( Englund, 1998 ). The effect of this on prevention of RSV disease needs more study.

3. Breastfeeding and severe lower respiratory disease:
   1. In a meta-analysis of 9 studies of the effect of breastfeeding on hospitalization for lower respiratory infections, Bachrach and coworkers found that among healthy infants in developed nations, exclusive breastfeeding for 4 months was protective of hospitalization for lower respiratory infection with a relative risk of 0.28(0.14-0.54). Controlling for maternal smoking and socioeconomic status had no effect on the risk ( Bachrach, 2003 ).

4. Breastfeeding and gastroenteritis:
   1. Dewey found decreased incidence of diarrheal illness in breast fed infants in the first year of life controlling for day care use and the number of siblings ( Dewey, 1995 ).

   2. A large randomized controlled trial in the Republic of Belarus provided breastfeeding support to mothers that resulted in a longer duration of breastfeeding when compared to a control group. Infants in the intervention group had a significant reduction in the risk for one or more episodes of gastrointestinal infections ( Kramer, 2001 ).

   3. An intervention that resulted in increased breastfeeding rates on the Navajo reservation was associated with a decline in the percentage of children having pneumonia and gastroenteritis of 32% and 15% respectively ( Wright, 1998 ).

5. Breastfeeding and premature infants:
   1. Premature infants fed their mother's milk were found to have decreased incidences of sepsis, meningitis, and necrotizing enterocolitis compared to infants fed premature formula. These infants were also discharged 2 weeks earlier than the formula fed infants ( Schanler, 1995 , Hylander, 1998 ).