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Probiotics - Their Influence on Immunity

Dr. Tanya Lee
8 June 2015

Probiotics - Their Influence on Immunity
by: Tanya Lee, H.BSc., N.D.

572 Bloor St . W Suite 201
Toronto, ON M6G 1K1

Health Centre of Milton
420 Main St. E Unit 102–103
Milton, ON L9T 1P7

Probiotics - Their Influence on Immunity


Probiotics are a popular intervention used by naturopathic doctors in the treatment of these atopic conditions, such as eczema, allergies, and asthma, as well as digestive disorders; in fact, epidemiological evidence has shown children with atopic diseases have different intestinal (probiotic) flora compared to healthy children.[1] Probiotics are defined as microorganisms, typically members of the genera Lactobacillus, Bifidobacterium, and Streptococcus, which naturally colonize the gastrointestinal tract.[2] Having a proper probiotic flora is integral for the proper functioning and development of the immune system.[2] The incidence of atopic conditions has been increasing over the years, and reasons for this increase may be linked to lack of exposure to natural probiotics at birth. Recent research has linked this reason to the fact that probiotics, much like found in breast milk, have the ability to balance immune responses through influencing the proper formation of the digestive tract in infants. Our probiotic flora does not change significantly after infancy, thus making proper colonization of intestinal flora at birth and during infancy crucial for developing a healthy and strong immune system as we age.[2] In order to fully understand this, we have to go back to the basics to know how probiotics prime the development of the immune system at birth.

The Role of Probiotics at Birth The Role of Probiotics at Birth

The neonatal immune system is an untapped environment, as this naïve system has been exposed to very little in the uterus. This means the immune system is a blank slate, with its development highly sensitive and influenced by anything it comes into

contact with right out of the womb; factors such as the infant’s gestational age, diet, and mode of delivery all impact this immune system right at birth.[2] When a baby is born, the first encounter with bacteria is through the vaginal canal, where it is exposed to commensal bacteria such as Escherichia coli, Enterobacteria, Enterococci, Streptococci, and Staphylococci.[3] The second exposure the baby has to bacteria is through the breast milk, and by the end of the first week — if exclusively breast-fed — the neonatal intestine is then colonized with Bifidobacterium.[3] Interestingly, vaginally delivered infants have the same bacterial colonization after 48 hours, whether breast-fed or not; however, differences in bacteria between breast-fed and formula-fed infants are detectable as early as day 7, and ultimately by 1 month.[2] This exposure to and colonization of maternal bacteria in the intestinal tract is crucial to the development of the digestive system and, therefore, proper priming of the immune system.[4] For this reason, vaginal delivery and exclusive breast-feeding in early infancy is highly encouraged if it is safe and feasible to do so. To solidify this notion, a number of epidemiological and clinical studies have found breast-feeding can significantly reduce the incidence of atopic disease and obesity in adolescent children, compared to those who were exclusively formula-fed, because of the probiotic content.[5, 6, 7] The digestive tract is the first formed piece of the immune system in an infant — a healthy digestive tract colonized by good bacterial will influence the development of a healthy, well-balanced immune system.

Limitations — What If I Had to Deliver Via C-Section, or Can’t Breast-Feed?

Despite concerted efforts to deliver vaginally and/or to exclusively breast-feed, it is unrealistic for any health-care provider to expect that this be the case for every new mom. There are unforeseen circumstances that are beyond anyone’s control that could result in a Caesarean section, or having to resort to formula-feeding, being safer to the health of mom and baby. In these circumstances, the immune system should then be influenced by giving probiotics in supplemental form in order to help encourage the development of a healthy digestive and immune system.

Benefits of Probiotics in Supplemental Form Benefits of Probiotics in Supplemental Form

A probiotic blend of bacteria similar to the bacteria colonizing the vaginal tract and breast milk can create an environment with similar health benefits to breast-feeding

and vaginal birth. A number of review studies recently carried out conclude that the ingestion of probiotics through dietary or supplemental sources can significantly help treat digestive concerns, such as infant colic, and prevent atopic disease by the time these children reach adolescence.[2, 8] Also, the valuable effects of probiotic supplementation on immune system are reflected in a number of studies that show a reduction in fever, cough congestion, flu-like symptoms, and antibiotic use in children afflicted by upper respiratory tract infections.[9, 10] Probiotics are not only beneficial in neonatal health, but also during the perinatal period. The probiotic colonization in pregnant women can also highly influence the atopic presentation in their children. A recent review found that probiotic supplementation in pregnant women can significantly reduce the risk of allergies and eczema in their children.[8]

In light of this strong research, many dominant commercial infant-formula manufacturers have added probiotics to their formulas to help improve the health of infants who cannot be breast-fed, which can be readily found on the market today.


Probiotics are a common supplement that are readily sold in health-food stores for many reasons, the most common and well-researched areas being the favourable effects on the immune system. Probiotic exposure of a newborn from the mother at birth, from the vaginal canal and breast milk, is important for priming the development of the digestive system and, therefore, balancing the immune system. It has been recommended to breast-feeding for at least up to 6 months in order for the baby to receive the proper bacterial colonization of the intestines.[6] Based on the beneficial effects to the neonatal immune system of exposure to bacteria in the vaginal canal, this is strongly recommended in neonates delivered via Caesarean section. If breast-feeding is not an option, for a number of understandable reasons, it is encouraged that infants receive these beneficial bacteria through an infant-appropriate probiotic supplement or a formula fortified with a blend of probiotics.