Holy cow is modern medicine still as smugly wrong as it’s always been. Every generation laughs at all the stupid stuff the previous generations believed, and then acts so confident that they’ve got it right this time.
And as a result you get unworthy nurses making moms feel intense shame for not “trying hard enough” to somehow magically produce milk.
Stay away from mommy blogs/forums. Those are the most toxic cesspools I've ever witnessed. Things are changing, some of the newer ones are not nearly as bad, but man the judgement is super real.
Nurses are one thing, but personally, the worst is family members who think they know better and don't understand the data and that times have changed.
FORMULA IS PERFECTLY FINE.
I have not seen result like this obtained in a randomized, controlled trial, and it is almost certainly false as stated: you're almost certainly exaggerating for effect, but doing that in scientific context is bad intellectual hygiene.
All results of this sort that I have seen have been purely correlational, and as such suffer from selection bias. This might be true, but the evidence is far from conclusive, and if such consensus exists among medical professionals, it only shows how susceptible they are to groupthink and parroting the stuff they heard from the cathedra.