<\/p>\n\n\n\n
In December 2025, the National Academies of Sciences, Engineering, and Medicine published a report titled<\/a>: \u201c<\/strong>Breastfeeding in the United States: Strategies to Support Families and Achieve National Goals.\u201d This report provides a framework for helping families meet their breastfeeding goals, with a focus on the health benefits of breastfeeding to both mother and baby, of which there are many. <\/p>\n\n\n\n While the physical and emotional benefits of breastfeeding are incredible enough in their own right, the immunological benefits are perhaps the most fascinating. In this article, we\u2019ll discuss how breastfeeding shapes your baby\u2019s immune system\u2014and the role kissing your baby can aid in that process (as if you needed another reason to do that!).\u00a0\u00a0\u00a0<\/p>\n\n\n\n Critically, the National Academies of Sciences report states that<\/a>:\u00a0<\/p>\n\n\n\n “Human milk provides all the nutrients necessary to support optimal growth and development for nearly all infants for the first six months of life and provides continued essential nutrition and developmental benefits for the duration of breastfeeding\u2026 infants who are breastfed \u2018more\u2019 versus \u2018less\u2019 may have a reduced risk of developing noncommunicable diseases such as asthma, otitis media, obesity in childhood, and childhood leukemia\u2026 <\/p>\n\n\n\n “In addition, a protective association of breastfeeding has been found for infant mortality, including sudden infant death, rapid weight gain and growth, systolic blood pressure, severe respiratory and gastrointestinal infections in younger children, allergic rhinitis, malocclusion, inflammatory bowel disease, and type 1 diabetes\u2026\u201d<\/p>\n\n\n\n For mothers, breastfeeding may also be associated with \u201clower rates of breast cancer, ovarian cancer, hypertension, and type 2 diabetes\u201d [1].<\/p>\n\n\n\n In addition to the physical health benefits it provides, breastfeeding can also be an emotional boon<\/a> for both moms and babies. The act of breastfeeding promotes bonding between mom and baby<\/a>, which helps babies to establish a sense of secure attachment<\/a>, reinforces<\/a> the voice bond that began in the womb, and provides<\/a> comfort and a sense of continuity for babies from pre- to post-birth [2].<\/p>\n\n\n\n Breastfeeding clearly provides babies with an overall foundation of emotional and physical wellness. But did you know that a mother\u2019s breast milk can change in response to pathogens <\/a>she picks up from her infant<\/a>, providing important immunological benefits as well? [3] <\/p>\n\n\n\n Newborns are born with immature immune systems, and in order to help their little bodies to fight off illness, a mother\u2019s milk will produce antibodies in response to pathogens<\/a> that either her infant carries, or that she was exposed to through other means [4]. These antibodies help to provide immunity to infants until their immune systems are more fully developed.\u00a0<\/p>\n\n\n\n There are multiple immunoglobulins, or antibodies<\/a>, that help infants\u2019 bodies to recognize and attack foreign invaders, or antigens, like bacteria and viruses. The most predominant types of antibodies found in breast milk include Immunoglobulin G (IgG), Immunoglobulin M (IgM), and Immunoglobulin A (IgA). <\/p>\n\n\n\n All three of these antibodies play a role in infant immunity and work together to provide a perfectly choreographed dance of protection against antigens. While there are proteins in breast milk, like lactoferrin<\/a>, which also help to prevent infections, let\u2019s examine how each of the antibodies in breast milk work to protect vulnerable bodies [5].\u00a0<\/p>\n\n\n\n The most predominant types of antibodies found in breast milk include Immunoglobulin G (IgG), Immunoglobulin M (IgM), and Immunoglobulin A (IgA). All three of these antibodies play a role in infant immunity and work together to provide a perfectly choreographed dance of protection against antigens.<\/p><\/blockquote><\/figure>\n\n\n\n Immunoglobulin G offers protection through two different mechanisms<\/a>. First, when a pregnant mother is prenatally exposed to pathogens, B lymphocytes (types of white blood cells made in the bone marrow) then turn into plasma cells that create antibodies<\/a>. These antibodies then pass through the placenta<\/a> in increasing numbers in the third trimester, and enter the fetal bloodstream, which protect<\/a> the infant for the first six-twelve months of life as his or her own immune system gradually becomes capable<\/a> of producing its own IgG [7], [8], [9].\u00a0<\/p>\n\n\n\n Second, IgG is transported via blood into the mammary gland and expressed into breast milk. While placental IgG provides systemic immunity, or the protection of blood and tissues throughout the body, this is not quite the case with breast milk IgG. Unlike IgA, IgG<\/a> is only produced in trace amounts in breast milk, with consistent ranges from around 0.1-1mg\/mL throughout lactation, to levels ranging from 10 to 100\u2009mg\/mL in colostrum and levels around 1\u2009mg\/mL in mature milk for IgA [10].\u00a0<\/p>\n\n\n\n IgG in colostrum and mature milk is mainly for local gut protection (the digestive tract from the mouth to the anus<\/a>) to prevent damage or infection. IgG in the infant gut targets and neutralizes<\/a> toxins, viruses, and bacteria, while helping to train<\/a> the infant\u2019s developing immune system<\/a> [11]. Infants must rely on their own production of IgG for systemic protection<\/a> that starts producing at around 3-6 months<\/a>.<\/p>\n\n\n\n Immunoglobulin M<\/a> starts production in the baby\u2019s liver prenatally at around 20 weeks, and is the first antibody that infants produce after birth [12]. IgM is therefore the baby\u2019s first line of defense against infections<\/a>, helping to \u201cbuy time\u201d systemically and in the digestive tract while IgG and IgA begin protection, and continues as placental IgG protection wanes<\/a>.<\/p>\n\n\n\n Last, but not least, is the star of the infant antigen-fighting show: Immunoglobulin A. IgA is the antigen that\u2019s most present in breastmilk, though it does work in tandem with IgG and IgM to support digestive immunity. In fact, a recent study found that \u201cIgA levels are the highest in colostrum\u2026 representing 90% of Ig, and then decline\u2026 in mature milk and [represent] 80% of Ig\u201d [10]. <\/p>\n\n\n\n IgA is the primary acting antibody on mucosal surfaces. Levels can increase in colostrum<\/a> in response to a respiratory or gastrointestinal infection a mother had while pregnant, specifically targeting mucosal surfaces and protecting the digestive and respiratory tracts<\/a> by coating the gut lining<\/a> and airways<\/a> in response to pathogens mom has encountered<\/a> in the environment<\/a> by binding to and neutralizing these pathogens<\/a> [13], [14].\u00a0<\/p>\n\n\n\n IgA also specifically targets any pathogens the baby is currently fighting<\/a>, developing through a fascinating immunological interplay between mom and baby [15]: the pathogens<\/a> a baby encounters can actually enter the mother<\/a> through her contact with the infant\u2019s saliva<\/a>, feces, skin secretions, and through the nipple<\/a> during feeding [16], [17], [3]. So that burning desire to kiss your baby all over her sweet little face (and belly, and hands, and toes, and\u2026) can actually influence your breastmilk to build up your baby\u2019s immune system!\u00a0<\/p>\n\n\n\n IgA also specifically targets any pathogens the baby is currently fighting, developing through a fascinating immunological interplay between mom and baby: the pathogens a baby encounters can actually enter the mother through her contact with the infant\u2019s saliva, feces, skin secretions, and through the nipple during feeding. So that burning desire to kiss your baby all over her sweet little face (and belly, and hands, and toes, and\u2026) can actually influence your breastmilk to build up your baby\u2019s immune system!\u00a0<\/p><\/blockquote><\/figure>\n\n\n\n But instead of the mother getting ill from these pathogens (since the exposure level is generally quite low and she has a more advanced, adapted immune system<\/a>) her lymphatic system encounters these pathogens and her aforementioned B cells are triggered to produce IgA. These cells then migrate through<\/a> her peripheral lymph nodes, spleen, tonsils, and exocrine glands, including her mammary glands, and express IgA into her breast milk to her infant. These antibodies then attach to the infant\u2019s intestinal lining<\/a> and act to block pathogens before they can take hold and cause infection. <\/p>\n\n\n\n While breast milk provides many benefits that formula does not, full-term formula-fed infants do indeed produce their own IgA beginning at 2\u20134 weeks<\/a>, but they have to rely more on IgM and prenatal IgG to prevent infections, as these antibodies and their developing immune systems are their main systemic and digestive defenses [18]. Some studies have found that IgM and IgG can even fill in in some cases where IgA is lacking to protect mucosal surfaces [19]. Our bodies are amazing, adaptable things!\u00a0<\/p>\n\n\n\n It turns out that even before your baby is born, your body is hard at work to build up her immune system\u2014and for breastfeeding moms, that work continues after birth. It\u2019s another good reminder that postpartum moms<\/a> are doing more than ever to promote the health and development of their babies, and that they not only need, but truly deserve<\/em>, the support of their families and communities during the first years of their babies\u2019 lives. <\/p>\n\n\n\n <\/p>\n","protected":false},"excerpt":{"rendered":"Encore plus de raisons d'embrasser son b\u00e9b\u00e9","protected":false},"author":149,"featured_media":24132,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_kad_blocks_custom_css":"","_kad_blocks_head_custom_js":"","_kad_blocks_body_custom_js":"","_kad_blocks_footer_custom_js":"","csco_singular_sidebar":"","csco_page_header_type":"","csco_page_load_nextpost":"","csco_post_video_location":[],"csco_post_video_url":"","csco_post_video_bg_start_time":0,"csco_post_video_bg_end_time":0,"footnotes":""},"categories":[5336],"tags":[5411,6379],"class_list":{"0":"post-24131","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-breastfeeding","8":"tag-breastfeeding","9":"tag-health-benefits-of-breastfeeding","10":"cs-entry","11":"cs-video-wrap"},"acf":[],"yoast_head":"\nPhysical health benefits of breastfeeding<\/span><\/h2>\n\n\n\n
Emotional health benefits<\/span><\/h2>\n\n\n\n
Immunological benefits<\/span><\/h2>\n\n\n\n
Breastmilk antibody production<\/span><\/h2>\n\n\n\n
Immunoglobulin G<\/span><\/h3>\n\n\n\n
Immunoglobulin M<\/span><\/h3>\n\n\n\n
Immunoglobulin A<\/span><\/h3>\n\n\n\n
How mom\u2019s interactions with her baby help build his or her immune system<\/span><\/h2>\n\n\n\n
What about formula-fed babies?<\/span><\/h2>\n\n\n\n
The bottom line on building your baby\u2019s immune system<\/span><\/h2>\n\n\n\n
References<\/span><\/h4>\n\n\n\n[1] National Academies of Sciences, Engineering, and Medicine; Division of Behavioral and Social Sciences and Education; Board on Behavioral, Cognitive, and Sensory Sciences; Board on Children, Youth, and Families; Committee on Understanding Breastfeeding Promotion, Initiation and Support Across the United States: An Analysis; Young M, Caswell JA, Asiodu I, editors. Breastfeeding in the United States: Strategies to Support Families and Achieve National Goals. Washington (DC): National Academies Press (US); 2025 Dec 26. 2, The Importance of Breastfeeding Across the Life Course. Available from: https:\/\/www.ncbi.nlm.nih.gov\/books\/NBK619940\/<\/a><\/p>\n\n\n\n[2] Modak A, Ronghe V, Gomase K P (October 09, 2023) The Psychological Benefits of Breastfeeding: Fostering Maternal Well-Being and Child Development. Cureus 15(10): e46730. doi:10.7759\/cureus.46730<\/p>\n\n\n\n[3] Lokossou GAG, Kouakanou L, Schumacher A, Zenclussen AC. Human Breast Milk: From Food to Active Immune Response With Disease Protection in Infants and Mothers. Front Immunol. 2022 Apr 5;13:849012. doi: 10.3389\/fimmu.2022.849012. PMID: 35450064; PMCID: PMC9016618.<\/p>\n\n\n\n[4] Lokossou GAG, Kouakanou L, Schumacher A, Zenclussen AC. Human Breast Milk: From Food to Active Immune Response With Disease Protection in Infants and Mothers. Front Immunol. 2022 Apr 5;13:849012. doi: 10.3389\/fimmu.2022.849012. PMID: 35450064; PMCID: PMC9016618.<\/p>\n\n\n\n[5] Fatimah, Massi MN, Febriani ADB, Hatta M, Karuniawati A, Rauf S, Wahyuni S, Hamid F, Alasiry E, Patellongi I, Permatasari TAE, Farsida. The role of exclusive breastfeeding on sIgA and lactoferrin levels in toddlers suffering from Acute Respiratory Infection: A cross-sectional study. Ann Med Surg (Lond). 2022 Apr 26;77:103644. doi: 10.1016\/j.amsu.2022.103644. PMID: 35638033; PMCID: PMC9142618. <\/p>\n\n\n\n[6] Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. B Cells and Antibodies. Available from: https:\/\/www.ncbi.nlm.nih.gov\/books\/NBK26884\/<\/a> <\/p>\n\n\n\n[7] Palmeira P, Quinello C, Silveira-Lessa AL, Zago CA, Carneiro-Sampaio M. IgG placental transfer in healthy and pathological pregnancies. Clin Dev Immunol. 2012;2012:985646. doi: 10.1155\/2012\/985646. Epub 2011 Oct 1. PMID: 22235228; PMCID: PMC3251916<\/p>\n\n\n\n
References Continued<\/span><\/h4>\n\n\n\n[8] Niewiesk S. Maternal antibodies: clinical significance, mechanism of interference with immune responses, and possible vaccination strategies. Front Immunol. 2014 Sep 16;5:446. doi: 10.3389\/fimmu.2014.00446. PMID: 25278941; PMCID: PMC4165321.<\/p>\n\n\n\n[9] Justiz Vaillant AA, Wilson AM. Transient Hypogammaglobulinemia of Infancy. [Updated 2023 Sep 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026 Jan-. Available from: https:\/\/www.ncbi.nlm.nih.gov\/books\/NBK544356\/<\/p>\n\n\n\n[10] Verhasselt V, Tellier J, Carsetti R, Tepekule B. Antibodies in breast milk: Pro-bodies designed for healthy newborn development. Immunol Rev. 2024 Nov;328(1):192-204. doi: 10.1111\/imr.13411. Epub 2024 Oct 22. PMID: 39435770; PMCID: PMC11659933.<\/p>\n\n\n\n[11] Janeway CA Jr, Travers P, Walport M, et al. Immunobiology: The Immune System in Health and Disease. 5th edition. New York: Garland Science; 2001. The distribution and functions of immunoglobulin isotypes. Available from: https:\/\/www.ncbi.nlm.nih.gov\/books\/NBK27162\/<\/p>\n\n\n\n[12] Keyt BA, Baliga R, Sinclair AM, Carroll SF, Peterson MS. Structure, Function, and Therapeutic Use of IgM Antibodies. Antibodies. 2020; 9(4):53. https:\/\/doi.org\/10.3390\/antib9040053<\/p>\n\n\n\n[13] Pietrzak B, Tomela K, Olejnik-Schmidt A, Mackiewicz A, Schmidt M. Secretory IgA in Intestinal Mucosal Secretions as an Adaptive Barrier against Microbial Cells. Int J Mol Sci. 2020 Dec 4;21(23):9254. doi: 10.3390\/ijms21239254. PMID: 33291586; PMCID: PMC7731431.<\/p>\n\n\n\n[14] Godding V, Vaerman JP, Sibille Y. Secretory mucosal immune mechanisms. Acta Otorhinolaryngol Belg. 2000;54(3):255-61. PMID: 11082760.<\/p>\n\n\n\n[15] Sompayrac, L. (2012). How the immune system works (4th ed.). Wiley-Blackwell.<\/p>\n\n\n\n
References Continued<\/span><\/h4>\n\n\n\n[16] Gerba CP. Environmentally Transmitted Pathogens. Environmental Microbiology. 2015:509\u201350. doi: 10.1016\/B978-0-12-394626-3.00022-3. Epub 2014 Oct 10. PMCID: PMC7149939.<\/p>\n\n\n\n[17] Churchill RB, Pickering LK. Infection control challenges in child-care centers. Infect Dis Clin North Am. 1997 Jun;11(2):347-65. doi: 10.1016\/s0891-5520(05)70360-3. PMID: 9187951; PMCID: PMC7134869.<\/p>\n\n\n\n[18] Stuebe A. The risks of not breastfeeding for mothers and infants. Rev Obstet Gynecol. 2009 Fall;2(4):222-31. PMID: 20111658; PMCID: PMC2812877.<\/p>\n\n\n\n[19] Eriksen C, Moll JM, Myers PN, Pinto ARA, Danneskiold-Sams\u00f8e NB, Dehli RI, Rosholm LB, Dalgaard MD, Penders J, Jonkers DM, Pan-Hammarstr\u00f6m Q, Hammarstr\u00f6m L, Kristiansen K, Brix S. IgG and IgM cooperate in coating of intestinal bacteria in IgA deficiency. Nat Commun. 2023 Dec 8;14(1):8124. doi: 10.1038\/s41467-023-44007-2. PMID: 38065985; PMCID: PMC10709418.<\/p>\n\n\n\n