I mean, at least a baby should be breastfed (as in a balance between formula and breastmilk) while there are those who solely use formula as their main means of feeding the baby but later in life that child has issues with their immunity like being susceptible on illnesses that are typically not fatal for most people.
That’s because breastmilk has all the nutrients to strengthen immunity later in life for a child. There is a difference between breastmilk and powdered milk: since formula is composed of numerous chemicals (it’s made from compounds) while breastmilk is from the mother. Is breastmilk healthier than formula?
It’s been a decade since I had to worry about such things. I remember reading that breast milk is - when available and plentiful - the preferred method. Formula is always second best. But this is a numbers game and I think the lab coats don’t say formula child will suffer consequence A as a result. It’s always there is a 5% higher chance of catching this or that (and I pulled that number out of thin air). But this is the margins I think I read about when it mattered.
Child #1 got supplemented with formula 60/40 at first; child #2 never had formula. Child #2 has spent more time in pediatricians’ waiting rooms. It’s a numbers game where you can do everything “right” and still not “win.” Big air quotes on those terms.
If you are a new parent or are about to become one and you’re reading this thread and you’re freaking out: please take a deep breath. You’ll figure this out.