How Breast Milk Boosts Your Baby's Immunity, Because It's Literally Like Magic

Breast milk is an incredible substance that science hasn't yet been able to replicate in formula — though they're getting closer, and the most important thing is always simply to love and feed your baby. Nevertheless, one of the things that separates breast milk from every other digestible fluid on the planet are the presence of adaptive antibodies: a tangible biological gift for however long you choose to breastfeed. Here's how breast milk boosts your baby's immunity, and what science says about the germ-fighting magic of nursing.

An article in Future Virology described breast milk as an "altruistic secretion," because it's one of the few bodily fluids that actively protects another creature. Antibodies in breast milk reflect a mom's immune history — the colds and flus she's seen in the past — at high concentrations, and protect against a spectrum of potentially harmful viruses and pathogens, including rotavirus. More fantastically still, breast milk changes to reflect the germs you encounter while you're breastfeeding, shielding your infant from threats in real-time. Even when you catch a cold, your milk marshals its cold-fighting forces, and passes them on to your baby. It's a boost, indeed.

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"During the first six months of life, the infant's immune system is still immature and relies on the antibodies present in mother's milk to act as its own," explains Julie Gladney, International Board Certified Lactation Consultant (IBCLC), of Ebb & Flow Lactation, in an email interview with Romper. That means fewer illnesses for breastfed babies, especially in the early months. "The literature clearly shows fewer cases of diarrhea, ear infection, upper respiratory infection," and even chronic diseases.

For a long time, doctors didn't know why breastfed babies contracted fewer illness than formula-fed infants, according to the breastfeeding site Kelly Mom. Scientists assumed it had something to do with human milk having less bacteria than cow's milk or formula. But doctors now understand that breast milk doesn't have fewer components than other liquids — it has more. You breast milk is literally swimming with antibodies, immune cells, and proteins, molecules and cells ready to attack threatening microorganisms, explained Kelly Mom. When it comes to immune protection, kale smoothies don't hold a candle to mom's milk.

But wait, there's more. According to a study in the Annals of Allergy, Asthma, & Immunology, breast milk is anti-inflammatory too, and inflammation is implicated in a number of troublesome conditions. Additionally, there's evidence that breastfed infants respond better to vaccination, getting more bang for their shot. Multiple studies even suggest that breastfeeding results in lower rates of celiac disease and allergic conditions. Breast milk primes and "stimulates" the immune system on multiple levels, offering potentially life-long benefits for a baby.

And what about the short-term benefits of nursing? In the winter months, every parent worries about their baby's susceptibility to colds and the flu. Can breast milk keep an infant from getting sick in the first place? What about helping your infant through an illness once they have one?

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"Breastfeeding doesn't guarantee protection against colds, but it is generally advised to continue nursing during minor illnesses to offer the nursling the continued many benefits of breast milk," Angie Natero, RN, IBCLC, tells Romper in an email interview. Combined with good hand hygiene and careful attention to symptoms, breastfeeding your baby is an exceptional way to nurse them through a winter cold.

As with everything in a parent's life, however, breastfeeding isn't a panacea. Breastfed babies still get sick, develop allergies, and suffer from serious conditions. Meanwhile, many formula-fed babies prove hardy, illness-averse creatures. When it comes to the immune system, genetics, nutrition, and luck have important roles to play. All of which is to say you shouldn't feel badly if you don't breastfeed, or don't nurse for as long as the World Health Organization recommends (two years or longer). Yes, breast milk gives an infant's immune system a boost. But if you're reading this article, whether you're nursing, planning to nurse, or thinking about switching to formula, you already care deeply about your baby, and that's the best protection in the world.

Check out Romper's new video series, Bearing The Motherload, where disagreeing parents from different sides of an issue sit down with a mediator and talk about how to support (and not judge) each other’s parenting perspectives. New episodes air Mondays on Facebook.