1.3 Effects of Breastfeeding alternatives
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![]() Key Points - Case Study AJoanne, aged 32, a regular patient, comes to see you when she is 12 weeks pregnant with her first baby. She has just returned from a trip around Australia and her pregnancy was confirmed by a doctor in the town they were in at the time. She has copies of her baseline blood tests with her and all are normal. Would you discuss breastfeeding at this visit?
What information would you give?
Why do breastfeeding alternatives have different effects?
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Why do breastfeeding alternatives have different effects?
These effects are due in part to the presence in breastmilk of substances and systems that act against infections and inflammation.
Secretory IgA (SIgA) | Secretory IgA is manufactured in the breast and acts against pathogens to which the mother has been exposed. Stimulated lymphocytes migrate from Peyers patches in the mothers gut and similar lymphoid tissue in the bronchial tree to the breast and produce SIgA in reaction to the pathogens present in the infant's environment (entero-mammary and broncho-mammary pathways). There are high concentrations of SIgA in colostrum to provide protection for the infant postpartum; by 4 months the infant consumes 75mg/Kg/day of SIgA. SIgA prevents the adhesion of bacteria and viruses to epithelial cells as well as neutralising viruses and bacterial toxins. Other antibodies (IgG, IgM and IgE) are also present in breast milk. |
Leukocytes | Similar to SIgA, leukocyte numbers are highest in colostrum, and fall to approximately 104 2x105 in mature milk1. The majority of cells are macrophages (85%) and small lymphocytes and play a role in protecting the breastfed infant and the breast by destroying pathogens by phagocytosis2. Macrophages and lymphocytes in breastmilk produce other active agents (SIgA, lactoferrin, complement, prostaglandins). They are also able to enter the infants circulation3. |
Lactoferrin | Lactoferrin is an iron binding glycoprotein that has a bactericidal effect on gram +ve and -ve bacteria as well having antiviral and antifungal capacity. |
Carbohydrates | Carbohydrates - in particular oligosaccharides, glycoproteins and glycolipids promote the growth of non-pathogenic bacteria in the infants gut as well as preventing the attachment of bacteria and other pathogens to the epithelial lining of the gut and other mucosal surfaces. |
Fatty Acids | Fatty Acids affect certain bacteria, viruses and parasites. They also enhance the development of the nervous system2. It is hypothesised that the fatty acid composition of breastmilk is responsible for the differences in cognitive development between those breastfed and those formula-fed,4 and may also impact on the development of allergic disease2. |
Lysozyme, α lactalbumin, complement, cytokines, growth factor, nucleotides | Lysozyme, α lactalbumin, complement, cytokines, growth factor, nucleotides present in breastmilk have all been shown to have an active role against pathogens2,3. |
Notes
- # Xanthou M et al. (1995) Human milk and intestinal host defense in newborns: an update
- # Hanson L (2004) Immunology of Human Milk: How breastfeeding protects babies
- # Hanson LA (2007) The role of breastfeeding in the defense of the infant
- # Caspi A et al. (2007) Moderation of breastfeeding effects on the IQ by genetic variation in fatty acid metabolism