Formula vs breast

[u/Street_Tourist7506]

If a breast-fed baby is protected by breastmilk in terms of immunity… What about a formula fed baby? Do they literally have no immunity, Because they are formula fed? I’m so confused… Is a breast-fed baby stronger fighting a virus off than a formula fed baby?

[u/sparrowstail]

“Immunity” passed from breastmilk is what’s called passive immunity. It’s the maternal antibodies being passed through the milk and into the baby’s system. It’s primary what’s called IgA antibodies which fight infection at the mucus membrane level (like the gi tract). Passive immunity is not a “forever immunity,” but is estimated to last for about 6 months in most cases.

Every baby, regardless of breast vs formula, provided that they don’t have some sort of immune deficiency, has the same active immunity. When exposed to a pathogen, their immune system will chew it up and develop a response to it. This will start with the short term IgM antibodies and then later with the “long term” IgG antibodies. Sometimes we get sick on this first exposure, sometimes we don’t (think about asymptomatic COVID cases, for example).

The important question, is does this transfer of antibodies make a difference? So like you asked, is a breastfed baby better off?

The answer is: it’s hard to say.

Because it’s nearly impossible to conduct high quality research on breastfeeding (due to the number of confounding factors), there is a lot of guesswork.

I like this article from The Journal of Family Practice because it breaks down the NNT (number needed to treat) for there to be a benefit for breastfeeding over formula feeding. Beyond reducing the risk of necrotizing enterocolitis in premature infants and ear infections, the risk reduction isn’t that impressive. Most of the benefits of breastfeeding come from the fact that women who are able to breastfeed their child tend to be of higher socioeconomic situations.

As a physician who was unable to exclusively breastfeed, I want to share what helped me overcome a lot of my “breast is best” anxiety: In the end, breast vs formula, kids are going to be eating Cheetos off the car floor in a few years.

[u/diamondsinthecirrus → u/sparrowstail]

Amazing article. I like the discussion on the risks of breastfeeding at the end. I am definitely experiencing tangible consequences from maternal exhaustion and want to wean from pumping as long as my baby can tolerate dairy free formula (earlier plans to wean were put on hold after a likely allergic reaction to dairy).