How to build your baby's Immunity, Naturally and FAST!

How to build your baby's Immunity, Naturally and FAST!

Breast Milk and Immunity

By Meghan McMillin, MS, RD, CSP, LDN, IBCLC

Hey Hey Mama, Welcome and Congratulations on starting your breastfeeding journey! Junobie is more than the World's First eco-friendly breastmilk storage bag, but we also value the opinions of qualified breastfeeding experts! Today we hear from our friend Meghan of Mama and Sweet Pea Nutrition on Breastmilk and Immunity! Breastfeeding, In addition to providing fat, carbohydrates and protein, the nutrition your baby needs, breast milk also provides special substances that boost your baby’s immune system. In a way, breast milk is nature’s antibiotic!

Passive Immunity and Breastfeeding

Before they are born, babies receive some protection against infections from the antibodies that are passed from mom through the placenta. This is what is known as passive immunity, because the baby is given antibodies rather than making them on their own. Breast milk also contains antibodies. Therefore, babies will continue to receive this passive immunity from their mothers for as long as they breastfeed.

Antibodies in Breast Milk

What’s truly amazing is that just one drop of breast milk contains a million white blood cells which release antibodies! So what exactly are these antibodies? Antibodies are a type of protein produced by the immune system to help protect against specific bacteria or viruses.

Mothers make these antibodies in response to pathogens present in her environment. Since a baby likely shares the same environment as their mother, he or she receives the protection it needs against the infectious agents they are most likely to encounter in the first weeks of life.

The most abundant antibody in breast milk is Secretory IgA. Secretory IgA works by coating  and sealing tissues, such as those in the lungs and intestines, and binding to pathogens to keep them away from these vital organs. Secretory IgA is abundant in colostrum, which is why it’s commonly referred to as liquid gold. There are other antibodies in breast milk all of which appear to keep rates of infection lower in breastfed babies compared to those who are formula fed. 

Other Immune Factors in Breast Milk

In addition to antibodies, breast milk provides several other important immune factors. Lactoferrin is the second most abundant protein found in breast milk. One of the key characteristics of lactoferrin is its ability to bind with iron. This is important because many bacteria need iron to survive. Lactoferrin slows the spread of bacteria by making the iron unavailable to them. In addition to being antibacterial, lactoferrin can also help protect against viruses, fungi and parasites!

Another important immune factor found in breast milk are human milk oligosaccharides. Oligosaccharides are a form of sugar or carbohydrate found in human milk. These sugars can resemble the binding sites of many pathogens along the lining of our gut. When a pathogen comes along it will attach to the oligosaccharide and then is unable to enter into the bloodstream.

Additionally, oligosaccharides serve as food for the healthy bacteria found in a baby’s gut, called Bifidobacterium Infantis (B. Infantis). The B.Infantis eat these little sugars, which allows it to flourish and colonize the baby’s intestines. Research has shown that the presence of B.Infantis helps fight against inflammation and protects babies from health conditions including asthma, atopic dermatitis, and colic. In premature babies, the presence of B. Infantis from the oligosaccharides is especially important in preventing necrotizing enterocolitis (NEC), a sometimes fatal infection of the intestines.


Breast milk is truly a fascinating fluid that supplies infants with far more than nutrition. It provides babies with immunity to protect them against infections until they can protect themselves. Secretory IgA, lactoferrin and human milk oligosaccharides are just a few of the immune properties in breast milk.There are many, many more and still some that we have yet to discover. Remember, it doesn’t matter if you breastfeed for 2 days, 2 months or 2 years. Every drop counts and can provide your baby with ongoing, immune boosting benefits!

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