Disease prevention is critically important to individual and public health. Breastfeeding is well known to provide immune protection and prevent various diseases in the perinatal period. Human breast milk is also accepted as the best nutritional source for the neonate and infant, and it provides other widely accepted benefits to the mother and child. Additionally, there are specific maternal benefits, including the delayed resumption of menses and subsequent reduced risk of anemia, as well as substantial association with bonding and emotional gratification. Indeed, there are even benefits to society overall through reduced child mortality rates, the economic advantages of breastfeeding over formula consumption, and the “environmentally friendly” aspects of lactation. It is estimated that improved breastfeeding practices could save 1 million to 2 million lives per year.
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Could early consumption of human breast milk also provide long-term benefits by protecting individuals from chronic diseases later in life? We examined the literature for evidence of long-term benefits of breastfeeding that may influence autoimmunity. While the evidence is not conclusive, there is enough evidence to suggest that breastfeeding may significantly alter the immune system of the suckling infant. Clues to this early influence are seen in the effects of breastfeeding on thymic size, the antibody response to vaccination, and increased tolerance to breast milk leukocyte antigens. Fundamental changes in the infant's immune system as a result of premature cessation of breastfeeding could lay the groundwork for later dysfunction in the immunologic controls necessary to prevent autoimmune disease or hypersensitivity reactions.
Autoimmune disorders are common and affect quality of life for millions of Americans. The incidence rates for some of these diseases have been increasing over the past several decades. Much of this increase can be attributed to increased levels of environmental allergens, pollutants, and lifestyle. The preponderance of evidence suggests that exclusive breastfeeding, for at least the first 6 months of life, can decrease the incidence of atopic allergies. In theory, enhanced maturation of the intestinal mucosal barrier could decrease translocation of protein antigens and thereby decrease unwanted immune stimulation. However, since there are multiple factors involved in allergic disease (eg, genetic history of atopy, environmental exposures), the effect of breastfeeding should be viewed as one word in a very long sentence. Future studies on this relationship should adhere to the standards described by Kramer
30 and should also require researchers to gather information on maternal diet as a possible confounding factor.
Although recent claims point to breastfeeding as preventive of IDDM, the evidence is far from conclusive. The most recent study cited above shows a protective effect.
50 Arguments in favor of the protective effect of breastfeeding include the apparent capacity of breast milk factors to enhance maturation of the intestinal mucosal barrier and, thus, enhance development of oral tolerance.
11 Unfortunately, the numerous confounding variables and potential for bias inherent in most of the study designs used make definitive inferences very difficult. If further research can confirm this protective effect, the implications for proactive interventions could be substantial.
In their early review of breastfeeding, Wold and Adlerberth
11 commented on the abundant protection provided to the neonate and infant by human breast milk and added that perhaps we should not expect lifelong immunologic protection as well. Even if breastfeeding is later proven to have no effect on the pathogenesis of chronic disease, there are enough short-term benefits from breastfeeding to justify its continued promotion as the exclusive nutritional supply for the newborn.
Osteopathic primary care physicians should promote breastfeeding at every opportunity. The American Academy of Pediatrics has listed specific steps that pediatricians and family physicians should take to promote breastfeeding and support those parents who have decided to breastfeed.
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The authors thank Zachary Comeaux, DO, William T. Blue, PhD, Edward P. Dugan, PhD, and Craig S. Boisvert, DO, for reviewing a draft of this manuscript. We also thank Mary Frances Bodemuller, MLS, Valeria Barfield, and Amber Cobb at the West Virginia School of Osteopathic Medicine Library in Lewisburg for their valuable assistance.