Parents often describe themselves as “totally smitten” with their new little one. Whether it’s their first baby or their last, parents can get lost in their newborn’s everything; their smell, the velvet of their skin, the tiny folds in their feet. While it’s not safe for other people to kiss your baby, some parents decide they just can’t resist! And who can blame them? Babies are extremely cute, totes adorable, and intensely kissable. But it’s not just because they’re cute! Science says maternal biology drives mothers to kiss their babies as a way to protect their immune system.
Moms kiss their babies as a means of sampling the micro-organisms their baby may have ingested. Because babies famously put everything in their mouth, it’s likely that they are exposed to more bacteria, fungi, viruses, and mold than the rest of us. Of course, in a healthy baby, this exposure mainly builds healthy immunities. The baby’s immune system learns to identify a wide variety of germs through these harmless exposures. Over time, those immune responses become a well-rehearsed routine, stomping out more common bacteria easily.
However, babies with weakened immune systems might actually get sick from one of those viruses. Newborns are especially vulnerable; it takes many months for babies to begin building a truly robust immune system. In the first few weeks and months of life, babies are particularly susceptible to contagious diseases. Naturally, these very same babies do a lot of exploring of their environment. They touch things, mouth things, suck on fingers and toes. Most of them spend a good chunk of time being held by adults who might be an unwitting carrier of something awful. It’s a little surprising babies don’t get sick more often, when you consider all this risk!
Mothers who breastfeed their babies have a special superpower - and it’s not (just) nipples of steel. Babies who feed at the breast actually exchange a little bit of saliva with breastmilk inside the mother’s nipple. I know this sounds like super weird science, but it’s all real! In that milk/saliva intermixing, the mother’s body receives signals from the baby. Scientists have proven the baby’s saliva can tell the mother’s mammary glands to create specific blends of breastmilk. Some babies request more fat in their milk; others order antibiotics for the germs on the pacifier they just gummed.
Yes, antibiotics! Breastmilk is a truly amazing substance; it contains over 40 enzymes, 1,000 forms of bacteria, and millions of live cells in all forms. Some of those components promote emotional bonding; others aid brain development, regulate blood sugar, and influence baby’s sleep cycle. In fact, breastmilk contains all five forms of antibodies! These antibodies, also called immunoglobulins, build the baby’s immunity at each nursing session.
Here’s where kissing comes in! Even if a mother doesn’t nurse her baby at the breast, she can still get a similar “custom recipe” of her own breastmilk. By kissing her baby’s cheeks and mouth, a mom can get a sampling of the germs her sweet angel might have eaten. My own doula reminded me, “If you’re around a sick person, make sure to cozy up to them. You’ll build immunities that will protect your baby even if you get sick.” Establishing germ exposure is the best way to ensure your milk has the specific immunities your baby needs to defend itself against illness.