You can locate your skeletal system, your digestive system, your nervous system - but where in your body does your immune system reside? Amazingly, it begins in your gut.
Your immune health can be helped or hindered in part by what you ingest. When your gastrointestinal tract if full of beneficial bacteria, pathogens are less likely to lead to illness. Your baby is just the same - his diet can impact how his gut acts and how his immune system develops. Compared to formula fed babies, those who are breastfed have guts with a higher proportion of beneficial bacteria.
Experts believe the first microbes to colonize baby’s gut are the ones that will predict health and wellness for life. One benefit almost everyone knows about breastfeeding is that it keeps babies from getting sick as often as formula-fed babies. Breastmilk provides secretory IgA antibodies which essentially coat baby’s gut and protect him from those germs most common in mom’s (and baby’s) environment. Researchers believe that individual components of mom’s milk (such as IgAs and oligosaccharides) provide protection in and of themselves, but they also work together to magnify the effects of this protection.
When a baby is given immune protection (through the placenta or through breastmilk) rather than making the immune factors on his own, this is considered passive immunity. It lasts the first few weeks of baby’s life (possibly longer) and can be prolonged by breastfeeding. Active or adaptive immunity begins when baby’s body starts to manufacture his own protections. After age one month, maternal antibodies in breastmilk decrease significantly - by as much as 90% - and baby’s system takes over. Baby’s gut bacteria continues to change throughout the early years - even until age 3. That doesn’t mean breastfeeding loses it power to keep baby healthy, just that the system is perfectly engineered!
Some amazing recent research deserves highlighting in relation to the protective effects of breastmilk on your baby’s immune system.
- The type of birth makes a difference - babies born by cesarean have different gut microbiota composition than babies born vaginally. Also, moms who are given antibiotics at birth have less of the beneficial gut bacteria than those who weren’t exposed.
- Premature babies may not have the same protective gut bacteria as term babies, but a protein in breastmilk, lactoferrin, may help to protect these babies against serious infection.
- Human milk has more than 200 sugars, whose roles and interactions are mostly unknown. No other mammal has so many! But researcher believe these human milk oligosaccharides (if you’re wanting the technical term) don’t feed the baby but instead nourish the beneficial bacteria in baby’s gut.
- If mom’s genes cause her to not produce some of these milk sugars, her children may have lower levels of “good” gut bacteria into toddlerhood.
- Group B Strep, a common pathogen found in mom’s genitourinary tract, can cause several health consequences for some newborns. Specific milk sugars, however, may protect against GBS infection for baby.
- Some recent research is showing that maternal vaccinations may have a protective effect on baby’s health - specific immune cells from mom may travel from baby’s intestines to his thymus to “educate” it to develop cells that attack specific infections.
Andreas NJ, Al-Khalidi A, Jaiteh M, Clarke E, Hyde MJ, Modi N, Holmes E, Kampmann B, Le Doare KM. 2016. Role of human milk oligosaccharides in Group B Streptococcus colonisation. Clinical & Translational Immunology, 5(8), e99.
Azad MB, Konya T, Maughan H, Guttman DS, Field CJ, Chari RS, Sears MR, Becker AB, Scott JA, & Kozyrskyj AL. 2013. Gut microbiota of healthy Canadian infants: profiles by mode of delivery and infant diet at 4 months. Canadian Medical Association Journal, 185(5), 385-394.
Bergstrom A, Skov TH, Bahl MI, Roager HM, Christensen LB, Ejlerskov KT, Molgaard C, Michaelsen KF, Licht TR. 2014. Establishment of Intestinal Microbiota during Early Life: a Longitudinal, Explorative Study of a Large Cohort of Danish Infants. Applied and Environmental Microbiology, 80(9), 2889.
Ghosh MK, Nguyen V, Muller HK, Walker AM. 2016. Maternal Milk T Cells Drive Development of Transgenerational Th1 Immunity in Offspring Thymus. The Journal of Immunology 197 (6): 2290.
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Sherman MP, Adamkin DH, Niklas V, Radmacher P, Sherman J, Wertheimer F, Petrak K. (2016) Randomized Controlled Trial of Talactoferrin Oral Solution in Preterm Infants. The Journal of Pediatrics, 175, 68.