Probiotics While Breastfeeding


What are probiotics exactly?

Probiotics are living microorganisms that are intended to benefit the body.  While microorganisms have a bad rap, like the term “germs” for example, many types are helpful.  Some help digest food, destroy disease-causing cells, and produce vitamins.  There are many different types of beneficial microorganisms.  This large network of microorganisms is collectively called your “microbiome”. Microorganisms can even be found in amniotic fluid and in the gut of an infant before they are born and continue to exist in the human gut for a lifetime.

Your microbiome changes.  This can be good or bad.  When the microbiome becomes disturbed in a negative way sometimes additional probiotic products may help your body return to a better state of health by balancing out the community of microorganisms that lives in your gut.  Treatment for health conditions using probiotics is still being researched.  It is hard to say which probiotics are helpful, how much to take for each person and who would benefit from specific types.

Many of the microorganisms in probiotic products are the same as or similar to microorganisms that naturally live in our bodies.  That is the point!  The seven microbial organisms most often used in probiotic products are Lactobacillus, Bifidobacterium, Saccharomyces, Streptococcus, Enterococcus, Escherichia, and Bacillus.  Each of these have different health effects and different stains within each of these can also vary in their effects on the body.




What does this have to do with breastfeeding?

Human milk provides many of these good microorganisms to the infant gut.  They help with digestive and immune function in the developing baby [1, 2].  According to one study, the most commonly isolated species of probiotics in breastmilk belong to the genera Staphylococcus, Streptococcus, Lactobacillus, and Bifidobacterium [3].  More sensitive studies have recovered an even higher diversity of microorganisms in breast milk including Enterococcus and Lactococcus, Veillonella, Gemella, Cutibacterium and Staphylococcus, Pseudomonas and Sphingomonas, but these results differ significantly between mothers [4, 5].   These microorganisms in mothers milk seem to come from the maternal gut, breast tissue, and infant oral cavity [6].  So, the mothers gut microbiome can be one factor that contributes to shaping the microorganisms in her milk.  These milk microorganisms then influence the baby’s microbiome and in turn can impact allergy and immune responses. 


So, what does this have to do with our babies and allergies?   

There are several conditions in infants that are likely affected by probiotic microorganisms.


Some studies have shown differences in the types of microbes of babies who do have colic and those who do not have colic.  A 2018 review of several studies involving the use of the probiotic Lactobacullus reuteri DSM 17938 to treat colic was successful in exclusively breastfed infants and no harmful effects were seen from giving babies this microbe [7].


Necrotizing Enterocolitis


This condition can occur in premature infants and can have fatal consequences.  A reaction to food components and the microorganisms that live in a premature baby’s digestive tract may contribute but the exact cause in still unclear.  A 2017 review of several studies showed that probiotics helped to prevent necrotizing enterocolitis in very-low-birth-weight infants. The results of each of the individual studies varied.  Probiotics that included both Lactobacillus and Bifidobacterium seemed to produce the best results, but it was not possible to identify the most beneficial strains within these large groups of microorganisms [8].

While no short-term side effects were seen, long-term effects of probiotics at a very young age is still uncertain.  There have also been instances where babies developed blood stream infections from the same microbes intended to be use for probiotic purposes [9]. 


Sepsis is a serious illness in which the body has a harmful response to an infection causing major organs to stop working and can be life threatening. The risk of sepsis is higher in infants.  One group particularly at risk for sepsis is premature infants.  A review of 37 studies (9,416 participants) found that probiotics were helpful in reducing the risk of sepsis in premature infants [10]. 



New research is also suggesting a link between milk microorganisms and pediatric asthma and allergy by way of modulation of gut microorganisms.  However, commercial probiotics for asthma prevention is still inconclusive [11].




Some studies and meta-analyses show that exposure to probiotics during pregnancy and in early infancy might reduce the risk of developing eczema in children. A 2018 meta-analysis included 27 randomized controlled trials (RCTs) and one controlled cohort study in a total of 6,907 infants and children exposed to probiotics in utero for 2 weeks to 7 months (via maternal oral supplementation) and/or by oral administration to the infants after birth for 2 to 13 months. Between ages 6 months and 9 years, probiotic treatment with single strains or mixtures that included Lactobacillus, Bifidobacterium, and Propionibacterium strains significantly reduced the risk of atopic dermatitis (eczema) from 34.7% in the control group to 28.5% in the probiotic group [12].

Allergen free options

Often, well-intentioned nursing mothers do not realize that their probiotics contain allergens.  Most over-the-counter probiotics are considered supplements and are therefore under less FDA scrutiny and regulations than food products.  This can mean that standard procedures, such as allergen cross-contamination prevention, may be less stringent [13]. 


The past year of working with lactating mothers has found that dietary logs can be inadequate due to such hidden allergens.  Often, when digging deeper into the mother’s intake, we discover a culprit found in a seemingly benign supplement, beverage, or seasoning.  Without a method to directly test human milk, mothers will often continue to methodically cut out whole food groups without realizing that the true problem is going undetected. 


Mother’s who are able to take probiotic supplements without infant allergic symptoms can certainly continue to do so.  Those who have removed suspected food culprits should review ALL supplements to ensure the eliminated food is not sneaking in undetected.  Specialized supplements with a “Free From” explicit statement (i.e. “Soy Free”) may be the easiest route.  Consult your physician for nursing and supplementation best practices and questions.


Microorganisms are shown to improve many common infant food allergy symptoms and more.  Not only does the above research show the role these "bugs" play in specific conditions, it is also interesting to consider maternal digestion impact.  Additional research is needed to determine if improved maternal digestion would reduce the amount of ingested food molecules that transfer to her milk.  


Katie Plummer, M.S.  &  Trill Paullin, Ph.D.



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  7. Dryl R, Szajewska H. Probiotics for management of infantile colic: a systematic review of randomized controlled trials. Arch Med Sci. 2018;14(5):1137–1143. doi:10.5114/aoms.2017.66055

  8. Thomas JP, Raine T, Reddy S, et al. Probiotics for the prevention of necrotizing enterocolitis in very low-birth-weight infants: a meta-analysis and systematic review. Acta Paediatrica. 2017;106(11):1729-1741.