Breastfeeding: Simply The Best
Human milk, the ideal food for infants, is perhaps the most widely consumed food in the world.1 However, in the United States, breastfeeding rates are less than ideal. The American Academy of Pediatrics, Committee on Nutrition, as well as other leading nutrition and health organizations recommend exclusive breastfeeding for the first 4 to 6 months of life.2 Although nearly 7 out of 10 infants are breastfed at some point during early infancy, by six months of age, only about 3 of 10 infants continue to be offered some breastmilk; the number of infants exclusively fed breastmilk is far less.3, 4 Due to the overwhelming evidence supporting health benefits associated with breastfeeding, encouraging the initiation and continuation of breastfeeding should be a fundamental objective of health care professionals.
An evidenced based review of approximately 400 individual studies has summarized some health benefits of breastfeeding for infants, and mothers.5 For mothers, a history of lactation is associated with a reduced risk for type 2 diabetes and breast and ovarian cancer. A reduced risk of acute otitis media and acute gastroenteritis, particularly in developing countries, is also evident in children provided breastmilk. Additional immune mediated diseases, such as asthma and allergy, have also been identified less often in breastfed children, compared to others.
Immune Components in Human Milk
Human milk is well known to contain immune protective compounds. In addition to immunoglobulins, cytokines, antibacterial proteins, nucleotides, and others, not all compounds in breastmilk responsible for immune modulation have been identified by name.6 Some of the more predominant immunocompetent cells in human milk are macrophages and polymorphonuclear neutrophils which have phagocytic activity. Other immunologic compounds provide protection for the infant directly, such as specific fatty acids, lysozyme (a protein that assists with bacterial lysis) and secretory immunoglobulins, while others help promote immune development and maturation (e.g., nucleotides, specific milk peptides, growth factors).7
The microflora also plays a critical role in the development and maturation of the immature immune system of infants. Breastfeeding confers immunity, in part, by passing on to the baby microbes in the milk for immune protection. Health promoting bifidobacteria make up 60 – 90% of the total fecal microflora in breastfed infants8, 9 derived from bifidus promoting oligosaccharides in breastmilk, or from the naturally occurring bifidobacteria within the breastmilk10. Immune protective effects of bifidobacteria have been well established.11Compared with babies who develop allergies, non-allergic babies have intestinal flora with more lactobacilli and bifidobacteria—the microbial species that also predominate in breastfed infants.
Protection for Allergic Disease
The influence of breastfeeding on the incidence of allergic disease has been studied and debated for several years, and its specific role in prevention still remains controversial.12Confounding factors, such as gene-environment interactions, methodological variables, length of breastfeeding, and exclusive breastfeeding compared to some nursing, may explain variability in results.
The protective relationship between breastfeeding and atopic disease appears strongest for infants at high risk of developing allergy - those with at least one first-degree relative with allergic disease.13 The risk of eczema during the first 2 years of life was slightly lower for breastfed infants of mothers with allergy, but this association was not found for asthmatic mothers.14 Additional interactions appear to influence asthma risk. A follow-up of children aged 8-10 years revealed a significantly positive association in the sub-group of children of whom were both overweight and exclusively breastfed for less than 3 months as infants. The relationship was strongest in children whose mothers had asthma, and more so in boys than girls.15
The duration of breastfeeding has been documented to influence occurrence of atopic dermatitis5, cow’s milk allergy, and wheezing in early childhood13 with longer breastfeeding duration decreasing the risk of recurrent wheeze, independent of maternal allergy or asthma status.14 Infants provided formulas of intact cow's milk or soy protein, compared with breastmilk, have a higher incidence of atopic dermatitis and wheezing illnesses in early childhood.16 Exclusive breastfeeding should be encouraged for at least 4 to 6 months in infants at both high and low risk of atopy and irrespective of a history of maternal asthma.16
In summary, long standing nutritional benefits, and more recent immunologic findings associated with infants of whom have been exclusively breastfed for at least 4 months continue to support that breastfeeding is still the best choice for infant feeding.
- Gavin A, Ostovar K. Microbiological characterization of human milk. J of Food Protection 1977;40:614-6.
- Gartner LM, Morton J, Lawrence RA et al. Breastfeeding and the use of human milk. Pediatrics 2005;115:496-506.
- Li R, Darling N, Maurice E, Barker L, Grummer-Strawn LM. Breastfeeding rates in the United States by characteristics of the child, mother, or family: the 2002 National Immunization Survey. Pediatrics 2005;115:e31-7.
- Ryan AS, Wenjun Z, Acosta A. Breastfeeding continues to increase into the new millennium. Pediatrics 2002;110:1103-9.
- Ip S, Chung M, Raman G et al. Breastfeeding and maternal and infant health outcomes in developed countries. Evid Rep Technol Assess 2007;153:1-186.
- M'Rabet L, Vos AP, Boehm G, Garssen J. Breast-feeding and its role in early development of the immune system in infants: consequences for health later in life. J Nutr 2008;138:1782S-90S.
- Field CJ. The immunological components of human milk and their effect on immune development in infants. J Nutr 2005;135:1-4.
- Vaughan EE, de Vries MC, Zoetendal EG, Ben Amor K, Akkermans AD, de Vos WM. The intestinal LABs. Antonie Van Leeuwenhoek 2002;82:341-52.
- Favier CF, Vaughan EE, de Vos WM, Akkermans AD. Molecular monitoring of succession of bacterial communities in human neonates. Appl Environ Microbiol 2002;68:219-26.
- Gueimonde M, Laitinen K, Salminen S, Isolauri E. Breast milk: a source of bifidobacteria for infant gut development and maturation? Neonatology 2007;92:64-6.
- Saavedra JM. Use of probiotics in pediatrics: rationale, mechanisms of action, and practical aspects. Nutr Clin.Pract 2007;22:351-65.
- Jackson KM, Nazar AM. Breastfeeding, the immune response, and long-term health. J Am Osteopath Assoc 2006;106:203-7.
- Greer FR, Sicherer SH, Burks AW. Effects of early nutritional interventions on the development of atopic disease in infants and children: the role of maternal dietary restriction, breastfeeding, timing of introduction of complementary foods, and hydrolyzed formulas. Pediatrics 2008;121:183-91.
- Snijders BE, Thijs C, Dagnelie PC et al. Breast-feeding duration and infant atopic manifestations, by maternal allergic status, in the first 2 years of life (KOALA study). J Pediatr 2007;151:347-51.
- Mai XM, Becker AB, Sellers EA, Liem JJ, Kozyrskyj AL. The relationship of breast-feeding, overweight, and asthma in preadolescents. J Allergy Clin Immunol 2007;120:551-6.
- Friedman NJ, Zeiger RS. The role of breast-feeding in the development of allergies and asthma. J Allergy Clin Immunol 2005;115:1238-48.